FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: My427stang on August 12, 2020, 01:24:49 PM
-
Joking around a bit, but I am taking 2 to Dale Meers dyno on the 14th. Brent took the day off, always awesome to hang with him and help on the dyno runs. We use the same dyno, but given it's a much longer drive for me, I wait until I have two.
I really need to get a local dyno, but don't have a lot of faith in the Land and Sea electrical ones out here, and love to go visit Brent, Dale and the gang there.
Two engines, one 457 cid, the other 461 cid, very different in execution. Details below each one. Happy to discuss, would love to hear guesses/estimates, and will report back
(https://i.postimg.cc/Qt2kXhHf/IMG-2708.jpg)
First up is a C-scratch 428, 4.25 stroker, 457 inches, 10.69:1 compression w/ Racetec 1.5/3.0 mm ring pack, .045 quench, flat top, CJ iron heads, 2.15/1.70 11/32 valves, CnC ported by Craft flowing just under 300 cfm, but a good exhaust valve and port. Cam is a Comp Cams custom hyd roller to my specs, 241/241 @ .050 single pattern, 112 LSA on 107, .633 lift, Brent's rockers, and a Ford tunnel wedge. We will make a pull or two with a pair of repop 465s, then bring out Drew's big guns, a pair of modified 3310s (750 cfm) with annular primaries and downleg secondaries (correct if I missed something Drew) Original recurved Ford distributor, no vacuum, with a Pertronix....and it DOES have a windage tray, it has a Canton screen type and an old school Milodon 9 quart oil pan.
(https://i.postimg.cc/JtwJWqYv/IMG-2710.jpg)
Next is a CX scratch 428, 4.25 stroker, 461 inches, 10.55:1 compression w/ Racetec 1.5mm/3.0 ring pack, .045 quench, full dish, Trick Flow heads, unmodified, but blueprinted and spring pressures corrected, 11/32 2.19/1.63, typically flow approx 335 cfm, but a little less exhaust flow and MUCH better chamber. Cam is a custom Oregon cams ground to my specs, hyd roller 233 @ .050 intake, 242 @ .050 exhaust, 113 LSA on 106.5, .600 lift, Brent's rockers, and an RPM intake that has had some light port matching and plenum work. It will have a QFT HR780VS carb, and a recurved Pertronix Flamethrower. (Funny I have never had one of these distributors, but two found their way to my shop)....and it DOES NOT have a windage tray, it has a Canton 7 quart T-pan.
(https://i.postimg.cc/gjLR55s3/IMG-2709.jpg)
It will be interesting, will the old school 457 out-power the new Trick Flow, or vice versa? Eager for comments and guesses, will post back on Sunday
-
Close heads, but a little more lift, "better" intake....Something tells me they will not be far apart. This is a good DYNO Day!
I don't know why but my gut says the iron headed motor will make more peak power, but feel the TFS headed motor may have the overall advantage across the curve. The subtle differences matter, and are hard to pin point. The divider mod may be the edge for the TFS motor., it definitely adds flow which it will suck up with the heads.....very interesting, at least to me.
My guess is a net difference, 22 HP either way....flip the coin.
-
My guess is that the Trick Flows will come out on top. Based on previous results posted here they are hard to beat. The Tunnel Wedge is gorgeous, though. Thanks for sharing the results.
pl
-
It will be interesting to be sure.
TW has more intake and carb, more compression, more cam by 8 degrees, more overlap by 5 degrees. Trick Flow has 40 cfm more intake flow, and smaller cross section in both head and intake and 4 cid
As a reference:
The Tunnel Wedge engine is similar to the all iron CJ I did a year ago, that made 520 HP / 530 TQ...added 1/2 point of compression, 4 degrees cam duration, narrower LSA and a TW.
The Trick Flow engine is similar to the the last painted TFS head that made 568 HP / 577 TQ, but 2 degrees less intake lobe, more overlap, quite a bit more more exhaust lobe, RPM intake instead of a PI worked by Joe, and a little more compression
They both should be fun, will be a good exercise in seeing if cam, intake and compression can catch a better cylinder head.
Going into this, the owners had two very different goals, we just be happen to be in a dyno drag race LOL. The TW was built as a period correct rowdy iron build for an documented Mustang racer, the owner valued the original look more than the added power of a modern head. The TFS is all hot rod, but has to pull a big Gal around with an AT w/ OD.
-
I guessed these in the Gonkulator, assuming for the all-important exhaust:
2x31 OPEN headers, 3.5 collectors 12" long.
Collector length makes a lot of difference so you might play with that if time.
For the TW 8v motor:
Twin 465 Holleys
Torq 563 at 4300
Powr 577 at 6000
Twin 3310D's (D for Drew)
Torq 575 at 4300
Powr 589 at 6100
For the TFS 4v:
Torq 587 at 4100
Powr 557 at 5500
The good old T-wedge would win down the track, assuming a suitable car.
Remember to Social Distance - stay at least 1 foot per 1000rpm away from any running dyno engine!
Nothing like the wholesome, clean sound of open headers.
-
This will be a real interesting comparison for sure. If the RPM were worked a bit, I would have to give the edge to the TFS heads, but the camshaft and dual carbs will offset the difference a lot. If the TW were on the other engine, no contest. Joe-JDC
-
The TW is the maker or breaker LOL.....from what I have seen the FE's seem to love them!
That was kind of what I was getting at in my first post.
I am with Joe...swap them and the TFS will eat the other one....as it is, I feel the old iron is going to beat the "kid".
-
I got in late last night, did a mad dash to dyno and back. I will do a good write up but a few key points until I get back
1 - Neither missed a beat, and the TW motor pulled clean as a whistle to the 6400 RPM range as we looked to find peaks
2 - Peaks were about the same in HP, 550-ish, but the Trick Flow motor made more torque at almost 595 ft lbs. I do however think the TW motor made slightly more HP. We had to split the day and had balancer swaps to do (see below) and I was unable to cool the room down for a final pull with the TW engine, typically after all the tuning is done, we do a final run. We did on the TFS engine, we did not on the TW. My gut tells me the TW engine would have pulled 565, but still have been lower on torque.
3 - The TW engine did not want any more than the 465 cfm carbs. Although Drew's carbs (absolutely gorgeous), made single digits more power when bolted on, we didn't bother to tune too much, because numbers were acceptable, and I knew the owner wouldn't want to buy new carbs for 10-15 HP and didn't want to get inside a set of loaner carbs if I couldn't make a sale. I think it was clearly a limit in the heads. The Craft CnC program just won't hang with the TFS head. Needless to say, the intake wasn't a bottle neck and I was AMAZED that the little carbs held the a/f mixture up through the peaks, but they did. There is NO doubt in my mind, on a set of deep breathing heads, Drew's carbs would have quickly overtaken the 465s
4 - If anyone is using a rebuilt balancer from Damper Docs, go grab the ring NOW and see if it comes off or moves. Don't even read the rest, run out there and check before you drive your car....I'll post pictures, but from pull #1, we had timing marks that didn't make sense. Turns out that first fire, the ring slipped, and then I reached down and pulled it right off. TDC had checked good at assembly, but all three pieces, ring, hub and elastomer, were not adhered. Luckily we caught it and swapped the balancer before we started comparing carbs. Thanks to Brent for pushing me to tweak the total more to try to get some power, if he didn't, we wouldn't have lost the timing marks, and likely wouldn't have made another pull with a carb swap...with date coded water pump, timing cover, some expensive pieces and 6400 RPM, it could have been ugly.
Talk about an odd discovery, Brent running the dyno up, me on the light, and I didn't have any timing marks. The joke on this dyno is that timing lights are always failing or damaged, so I checked connections to be sure and then had him shut it down. When all looked good, we looked at the elastomer and it was in 1 piece but looked strange, I grabbed it and the ring popped right off. Swapped the balancer, and what we thought was 38 degrees total, was really 45 degrees, which tells us it was bad from the first fire
Including this build, I have only used them twice, but I already went back to the the prior customer to be sure he checked his. I won't ever use another, it came apart easier than you could imagine. Like it was held together with a lubricated strap....but was dry
More to come in a bit, getting pictures and pull numbers together and will post details.
-
Congrat's on the good numbers and finding the balancer issue before it caused any harm.
Can't wait to see the details.
pl
-
OK, so here is the more exact data. In both cases, realize the chart somehow is slightly off the graph, I tend to use the data off the chart because it has more info. Not sure why, but the graph extrapolates slightly differently if you are comparing.
But first....a good look at the Damper Docs damper...just seemed to be held together with something that didn't stick to anything. Buyer Beware! They do have a good rep, we'll see what they say
FYI - I always install with an installation tool, and it came to me in a box from the company. Given that it started slipping on initial fire, my guess is it was a bad bond from the start. Talk about lucky, if it would have let go, it would have been a very different day!
(https://i.postimg.cc/J750nGCX/Balancer.jpg)
Here is the 457, although it would look like it was still climbing on the graph, the numbers were leveling off after 6000. Watching the dyno I saw 6400 on the tach, without so much as a burble. It was very clean, not sure why the chart stopped where it did, must where it stopped collecting based on load. This was built to be a 6000 rpm peak, so it's where we want it, so no surprise. It liked 38 degrees of timing, no surprise there either
Ironically, the two 465s had the slightly higher HP peak, and the two 750s had the higher torque peak, backwards to what you might think. 545/545 vs 544/558, HP is within spitting distance and I would call them equal, but it does show Drew's carbs were working nice, and should tell people yet again that "small carbs for more torque" is a fallacy.
I make no excuses for this engine, it is a fun and bad mofo, but there were some differences in the dyno runs when you look at both. First, note the engine temps, I think there was 10 more HP if we finished up with a cool down, however, losing the balancer, checking everything out, and doing some carb swaps ran me out of time and I wanted to give both motors time on the pump. Second, we saw the most torrential rain storm I have driven in for a long time and the weather changed significantly at lunch time for the second engine. Although the dyno will adjust, I do think the TW would have been called the winner for peak HP if things were a bit more stable, but likely not by a wide margin. In a 4 speed 4.11 68.5 Mustang, this will be a stout runner
(https://i.postimg.cc/WzT48Pgt/461Dyno.jpg)
450s
(https://i.postimg.cc/Prfx8TdR/TWwith450schart.jpg)
(https://i.postimg.cc/HkVkBzc0/TWwith450sgraph.jpg)
750s
(https://i.postimg.cc/L5xZZswm/TWwith750s.jpg)
Here is the 461, it was a pretty easy dyno run after switching balancers back. We ended up at 32 degrees of timing. A little less than normal, but in the ball park, likely due to the shallow dish and tight quench. This was a gentle and happy build. 558/594 peaking at 5750 RPM. It also had no problem at all hanging in as high as we wanted to pull. This one is going in a 63 or 64 Gal, with a 4 speed AT Chevy box conversion. The curve should very nice for the use. Less drag car than cruiser, but should still be able to scare wives and small children at ease :)
(https://i.postimg.cc/zBnBTfL9/457Dyno.jpg)
(https://i.postimg.cc/mkjg66yj/TFS461-Graph.jpg)
(https://i.postimg.cc/3JLwXVRJ/TFS461-Chart.jpg)
In the end, two very happy motors, one more snarly and vicious attitude than the other, but both will be very strong runners.
I will put the exact build details in the dyno section in separate write ups
-
Very cool. Thanks for sharing. What do you attribute the big difference Between the two engine at lower rpms to? Heads? Intake? Cam? All of the above?
pl
-
The CJ heads have a huge port volume and the TW has a med riser port but huge plenum and short runners. BBM TW would be much worse
The TFS heads have a small port volume, more flow, and the RPM has longer runners and smaller plenum, that makes a really responsive port
Additionally, the bigger intake lobe and more overlap required to hit the desired RPM peak, you trade for low end. This engine would have likely been very happy with a medium riser dual plane, as many of us discuss here.
-
Man!
There really is a ton of information from this comparison test.
Say no to stock balancers. I know many of us have used them for years with no problems (me too), but if that outer ring would've come off at 6K it would still be bouncing around that dyno cell. If you're gonna see 5K plus regularly, it's a bad idea.
Note that the iron head motor had a full CNC port and chamber finish and was still 40cfm short of the Trick Flows. Point being a better part of the cost of the Trick Flows was spent on the iron heads only to come out with an inferior part. I know, cast iron is cool...but it's kind of silly.
That said, having a vastly superior head did not guarantee a clear winner in horsepower. With the number of 600 horsepower builds with Performer RPM intakes, I at least was surprised.
The difference between the big 'n little carbs is surprising. Reading these results and others seem to indicate that carb size, unless they are too small, and header primary size seem to have very little to do with total horsepower production...although some seem to fixate on them.
The hydraulic roller cam seems to work. Putting a "squishy" cam in an FE is, well, umm, "icky". But these crisp dyno sessions going beyond 6K is impressive.
The single pattern camshaft is not dead. Some engine builders may think it is...but this comparisson says otherwise.
Thanks Ross, for sharing this information. Seems like you had fun, except for the rain. It rained here in sunny SoCal. 104* outside and rain.
-
Man!
There really is a ton of information from this comparison test.
Say no to stock balancers. I know many of us have used them for years with no problems (me too), but if that outer ring would've come off at 6K it would still be bouncing around that dyno cell. If you're gonna see 5K plus regularly, it's a bad idea.
Note that the iron head motor had a full CNC port and chamber finish and was still 40cfm short of the Trick Flows. Point being a better part of the cost of the Trick Flows was spent on the iron heads only to come out with an inferior part. I know, cast iron is cool...but it's kind of silly.
That said, having a vastly superior head did not guarantee a clear winner in horsepower. With the number of 600 horsepower builds with Performer RPM intakes, I at least was surprised.
The difference between the big 'n little carbs is surprising. Reading these results and others seem to indicate that carb size, unless they are too small, and header primary size seem to have very little to do with total horsepower production...although some seem to fixate on them.
The hydraulic roller cam seems to work. Putting a "squishy" cam in an FE is, well, umm, "icky". But these crisp dyno sessions going beyond 6K is impressive.
The single pattern camshaft is not dead. Some engine builders may think it is...but this comparisson says otherwise.
Thanks Ross, for sharing this information. Seems like you had fun, except for the rain. It rained here in sunny SoCal. 104* outside and rain.
Thanks for the good words.
I agree with you on the heads, I will say though, in this case, the owner and I had a long discussion...no, weeks of discussions...and I enjoyed it. We wanted to make sure were going the right way with his car. It actually almost was a BBM or TFS headed build at one point but heritage won.
This car has a pedigree, it was a Ford racer campaigned by a West Coast guy, and the owner wanted it to remain in a "could have been raced then" configuration. Not an actual copy, but what seemed logical for a car raced when it was raced. So we went into it knowing that. In fact, thegoal was to hit 530-ish HP, and accept a 50 HP loss for heritage. I was happy to beat it and hit the RPM peak where we wanted it
The TFS headed engine could likely have gone up quickly, it would have let itself loose with more cam
What I think we see here is one engine using all of its cylinder head, the other using all of it's camshaft. It was a cool comparison
As far as the balancers....man oh man, can you imagine if it let go? I will look closely, never know if the ring has a little crack, that would certainly expand with a little heat and cause the bond failure.
-
Ross, those are great motors and will obviously work well for your customers. Having said that, the curves shown on the dyno data have been smoothed, and are therefore a little misleading. Look at the second set of results. The HP curve is nearly flat from 5500 to 6250, at 550 HP. Looks great! Now, look at the corresponding numbers:
5500: 555 HP
5750: 558 HP
6000: 545 HP
6250: 547 HP
The data shows that something is happening with that engine between 5750 and 6000 RPM, because power is dropping off. And it is dropping off in a non-linear fashion. I will almost guarantee you that it is valvetrain control, probably the hydraulic lifters giving up. Seen it literally dozens of times before on my dyno, and a couple times I've pulled the hydraulic lifters and replaced them with solids, just to see if it was the lifters. And it was. There's a quick blurb in my book about it, along with a graph.
Now let's look at the first set of data. The graph shows a steadily increasing horsepower level from 5500 to 6250. Again, it looks great. Now look at the data:
5500: 539 HP
5750: 545 HP
6000: 545 HP
6250: 544 HP
The HP is rising up to 5750, then it goes flat. But that is not what the smoothed curve shows. Again, it looks to me like something is happening with the valvetrain between 5750 and 6000 RPM that is flattening the curve. Again I would suspect the hydraulic lifters.
The moral of the story is, look at the numbers, not the smoothed curve. Or else, take the smoothing out of the curve plotting algorithm. You may notice on the dyno results that I post that the curves are rather jagged; they don't look as nice, but they may tell you more.
Also, I know everyone loves hydraulic lifters, but I think they should never be used on a performance engine that is destined for more than 5500 RPM. JMO, of course ;D
-
Jay, that was my point too, the curves are just for trending and posting pictures :)
However, to address what looks like valve float. We saw that and went back and looked at all the runs on that engine, and it isn't there anywhere else. Maybe the manual dyno loading. Can't say what exactly happened, but it wasn't there in the others, and this is a very simple and unaggressive lobe with pressures on the money.
That being said, I had one v/c seeping a bit, I'll go back and look for any tracks on the valve tip, but I am confident after seeing more data than I hung here that it is not losing control
I agree with you though, the curves don't give enough data points and with smoothing don't give you detailed data, just gross behavior
-
Jay, for every instance that you've seen a hydraulic roller cam give up at 5500, I can show you one that has either gone to 6200, 6400, 6600, 7000, or 7500. Case in point...
(https://live.staticflickr.com/1847/43840026675_9f0eeab339_z.jpg)
(https://live.staticflickr.com/1853/30878468088_3d69a962f6_z.jpg)
I think the majority of the issues that you have seen personally have been the combination of parts that were used. The cam lobe has to match the lifter, the valve size, the spring pressure, the oil viscosity, etc., i.e. changing to a high quality lifter doesn't do much if the valves are heavy and there's not enough spring pressure....running 11/32" stems doesn't do anything if the camshaft is overly aggressive, etc.
With all that being said, I never take seriously the numbers that are at the very, very top of the rpm range on a manually driven dyno. I haven't looked at the sheets closely, but I'll say that since the operator is controlling the amount of load as well as the acceleration rate, the end numbers at the very end of the pull can be skewed by how he's loading the engine while anticipating the end of the pull.
Either way, Ross had planned a 5500-6000 rpm peak for both of these engines and had not intended to go higher than 6, so it looks like he accomplished his goal. The TW numbers may have flattened off, but that's pretty typical of any camshaft when it gets to the peak....they have to stop somewhere LOL
Switching gears...
I've learned over the years to not get nervous at a dyno session. It used to be that I would keep myself up a lot of the night before, but I've calmed myself down quite a bit. With that being said, I'm 100% calm when it's someone else's engine...LOL It's a blast to just go and turn wrenches and have fun. I always enjoy it when Ross comes to visit.
I know it's easy to say at this point in time, but these two engines pretty much behaved the way Ross and I thought they would. We had discussed how we thought they would be equal on horsepower but the torque difference would be significant. On one hand you have a really high performing cylinder head with a short cam and on the other hand, you have a lower performing cylinder head with a bigger cam. Torque will usually be equal or less on an engine where the camshaft is trying to make up for head flow.
The balancer was something I've never witnessed before. I also think it spun when we first started the engine. After the first couple pulls, we pulled a plug to look at it and the timing mark was at the very bottom of the strap. I asked Ross where he had the timing set and he said around 38, so I said let's pull some out and try it. When I fired it back up, Ross gave me this look like, "What's going on??" And when we are all wearing face masks and I could still read his facial expression, that shows how dire the situation was...LOL There wasn't a timing mark on the balancer to be found. It's a miracle that one of us didn't catch a Fomoco balancer to the face.
Both these engines were really nice pieces. My fave was the TW engine, but I'm a sucker for factory parts painted blue.
-
Nice work, good catch/save on the damper, and solid engines. Lots of information to digest and mull over. Joe-JDC
-
How much oil did you run in each pan?
thanks,
pl
-
Full to dipstick, 8 in the Canton, 10 in the Milodon
-
Iam looking at the dyno headers and think the tests should have been done with the ones used in each application. A few years we did a couple of days of testing at Teds and found a world of information on HP and torque with different headers. We used averages to determine the winner. This was a 390 stock eliminator engine.
-
I am looking at the dyno headers and think the tests should have been done with the ones used in each application. A few years we did a couple of days of testing at Teds and found a world of information on HP and torque with different headers. We used averages to determine the winner. This was a 390 stock eliminator engine.
Kirk, we all have ideas on how to test better, but in the end you play the hand that you are given. Neither car owner has the headers they will run and street headers don't always fit the dyno. Valid, but not executable in this case. I am a fan of exhaust tuning though and agree it is an area many overlook.
Are you willing to share your information you gathered? I think we'd all be interested, in this case, especially for a Mustang shock tower car...
-
My biggest surprise is that the Tunnel Wedge didn't come on stronger after 3500 rpm or so. You mentioned other factors, though. It was really cool to see so many different parts on two different engines at the same time. Yet about the same peak hp. It would of course be really neat to swap parts around from engine to engine to try all the various possible combinations, but that would take way more time than it'd be worth. This was about as good a comparison as you can do in one shot. Loved it.
pl
-
Would have been cool to see a 2x4 medium riser on both and the rpm on the other.
-
I am not sure its valve float - certainly possible. I am more interested in those A/F numbers. You have a pretty sizable variance left to right. I sometimes see that with my stuff when running dual planes at low load but it usually tightens up at WOT and higher RPM. I know my dyno seems to have a pretty voracious appetite for O2 sensors and have found out that the Bosch 17014 is the correct and less expensive replacement for the overpriced ones that ECM wanted to sell me. Did you try swapping the connections from left to right to verify the data?
If those 14:1 plus numbers are valid you had some potential trouble on your hands without really seeing it. Since collector O2 numbers are an average of four cylinders, a 14:1 average could mean that you have a really lean single hole in that bank. Detonation or a lean misfire will upset ring seal and can give you the funky numbers that Jay is seeing. Looking at the data without having more information my first guess is that the 750s were on the way to kicking major behind but they starved out for fuel before reaching any potential. I know that a tunnel wedge does not provide easy connection - but a vacuum hookup can clue you in on airflow tract restrictions. On pump gas stuff we usually see A/F readings between 12.8 and 13.2 with some variance on combinations, but a 14+ will always get me looking at parts and plugs.
-
I am not sure its valve float - certainly possible. I am more interested in those A/F numbers. You have a pretty sizable variance left to right. I sometimes see that with my stuff when running dual planes at low load but it usually tightens up at WOT and higher RPM. I know my dyno seems to have a pretty voracious appetite for O2 sensors and have found out that the Bosch 17014 is the correct and less expensive replacement for the overpriced ones that ECM wanted to sell me. Did you try swapping the connections from left to right to verify the data?
If those 14:1 plus numbers are valid you had some potential trouble on your hands without really seeing it. Since collector O2 numbers are an average of four cylinders, a 14:1 average could mean that you have a really lean single hole in that bank. Detonation or a lean misfire will upset ring seal and can give you the funky numbers that Jay is seeing. Looking at the data without having more information my first guess is that the 750s were on the way to kicking major behind but they starved out for fuel before reaching any potential. I know that a tunnel wedge does not provide easy connection - but a vacuum hookup can clue you in on airflow tract restrictions. On pump gas stuff we usually see A/F readings between 12.8 and 13.2 with some variance on combinations, but a 14+ will always get me looking at parts and plugs.
Yeah, this one eats O2 sensors as well.
I think the one that Jay was speaking of having valve float issues wasn't the TW engine that showed the 14's A/F.
-
First, I appreciate everyone's input. Brent's all over it. One of the things here is that having two builds in one post is getting things crossed up, I likely won't do this again LOL
1 - The 750 vs 465 Tunnel Wedge engine was the one that had the lean second pull, NOT the engine Jay was talking about the top end burble he saw.
It's hard to get into decisions around a dyno in a post. I'd have to write a book about what we discussed and everyone who runs on dyno knows, dyno day is development, but sometimes there's more than just trying every possible combo unless you are in Kirk's racing scenario or the herculean effort Barry and Blair did on EMC. However, we didn't miss the A/F in the least. In fact it was THE reason for the decision to stop on the 750s. As I looked at a loaner set of 750 carbs, set up for another engine and running well on that engine, the potential cost/benefit to the owner, I made the purposeful decision to NOT go into the 750s because I didn't think the cleanup would yield enough HP to warrant a purchase of a second set of carbs.
In hindsight, that should have been in the original post.
I think there might have been some small gains in power with the 750s, but given the existing carbs had exceeded expectations by almost 20 HP and nailed the peak RPM (and shift point) without going fat, it wasn't a tough call for me. Now, if the 465s didn't have clean pulls, we would have been all over the 750s. Believe me, I told the owner (repeatedly) not to expect much from the 465s. I ate crow on that prediction. As most others, I honestly expected the 465s to go pig rich at the top of the pull as the booster dealt with that airflow and anticipated that correcting the HSAB would give us fits down low. None of that happened...if we swapped heads from one engine to the other, with the right cam for the new combo, I think it would have been a different story, but that's bench racing. I hadn't used these carbs before, but they behaved far better than the old flamethrower tunnel ram mechanical secondary 450s.
2 - The right side being slightly leaner seems to be a characteristic of this dyno, and relatively consistent for this day, although not always the case as I look back through other builds.
If you look at mine and Brent's posted pulls, it seems to be a constant variance left to right. Sometimes it's tighter, sometimes not. I can't answer to that, but we did pull plugs after that Tunnel Wedge pull and expected them to show some distress, they did not. In fact, I think Brent's comment "is it yellow and glazed?" as I pulled the plug out of that side. I did not switch O2 sensors, but if the leads are long enough, that is a GREAT diagnostic tool.
Believe me, as a guy who really only does pump gas builds, that is where I focus, and yes, lean can get you sideways, but needless to say, mixture is not the only thing that drives detonation and the engines are really right (tight quench, the right plugs, any potential hot spots cleaned up, conservative compression and good cam and ignition timing) with room for gas variance, plus in the car, it generally fattens up a bit
I suppose that if we are going to hang some data, we all better be ready to answer up for that data, but considering there are hours in the dyno room, sometimes some critical points or money-based decisions are dropped off in the minutes of hanging a post
My biggest punch line on these builds yet again is: Good heads and chambers are the easiest path to big numbers The difference in these two is not only power though, look close at the two pictures for which belongs in a late 60s/early 70s ex-Ford racer and which belongs in a custom rack & pinion, Chevy 4 speed electronic tranny, 4 linked street Galaxie. I did put these two as a comparison, but they don't really compare in use.
-
The A/F ratio splits all come down to how well the intake is balanced and well the carbs work. If you look around at a lot of dyno sheets, most guys don't even show both sides, they just focus on one.
If you bolt an aftermarket intake on without balancing all the runners/ports, you can see up to a point split sometimes. The more and more work you put into the intake and the carbs, the closer they get. Makes perfect sense as different flow rates through the intake manifold will limit the engine on how it can pull on the carb from side to side.
(https://live.staticflickr.com/65535/50195135738_a7e005ecb8_z.jpg)
Another very important thing is that an air cleaner sometimes will straighten the flow out and balance the air/fuel ratios. We can tune until the cows come home on the dyno, but it's really a different scenario in the car, with air cleaners, exhaust, underhood air flow, etc. I will tell customers that we can get them close here, but it's ultimately their responsibility to follow-up when the car is going down the road.
-
Now you are beginning to see why I always try to get the dual planes to flow closer to each other. There is a ~30 cfm disparity between the lower and upper planes on the RPM or any PI intake as cast with a simple gasket match. Joe-JDC
-
Now you are beginning to see why I always try to get the dual planes to flow closer to each other. There is a ~30 cfm disparity between the lower and upper planes on the RPM or any PI intake as cast with a simple gasket match. Joe-JDC
Joe, you certainly make the dual planes (and others) perform. We need to get an apprentice to stand by your side, if you don't have one already, just to capture your techniques for the next 10 years!
-
Ooofff :o I just last week was looking into sending a balancer to Damper Doctors.
-
Ooofff :o I just last week was looking into sending a balancer to Damper Doctors.
I think that's where Dr. Kevorkian got his start.
-
Ross,
Did you take vacuum readings on that 465 cfm setup?
-
Frank, I did not. Would have been good data, but didn't reconfigure after the 750s
-
Looks like the Gonkulator hit the TFS combo pretty much right on.
On the T-Wedge:
I grabbed the head flows (295 intake, 202 exhaust (awesome) at .600) from the dyno section, which made some difference, but still, the Gonkulator comes in 9% too high in peak power for both carb sets, which is 9% of a big number ie about 50hp.
Usually the Gonkulator is within about 3%-4% on predictions so this is really way out there, maybe something more to sort out somewhere but I'd have no idea what.
Still, it's very true, something to be said (a lot) for the old-school look. I just built a bone stock 390/"300hp" here, makes about half the power of this pair, but it just and sounds looks so 1964 in there with all that black iron and gold stampings. Hey, it made enough torque to rip the motor mount out during testing (fan banging against the fan guard!) The original gold "snorkel" air cleaner sure makes a strange howling noise compared to the open 14x3 we are all used to, but it's only costing about 2 net ponies so worth the old-school look. Well then again we all threw those in the trash on day 2 so maybe it's not so old school.
-
“Ironically, the two 465s had the slightly higher HP peak, and the two 750s had the higher torque peak, backwards to what you might think. 545/545 vs 544/558, HP is within spitting distance and I would call them equal, but it does show Drew's carbs were working nice, and should tell people yet again that "small carbs for more torque" is a fallacy.“
Makes total sense to me.....
I run that Dove Tunnelwedge with the changable tops.
Ya know, the one you can fit your head into the plenum.
I built the carbs to idle nice and rich for an 800rpm smooth idle and the annulars were used to aid low throttle opening cruise type conditions with the intake I have.
Different engines.... diff results.
I seriously need to get outta the shop and drive the car more
-
Another thought on the 465 vs 750 oddity. Since it is obvious that the 465's will supply enough air, to get max HP at WOT, with this combination, there is either a problem with the 465's mid range or the 750's high range flow.
Although it wouldn't seem unlikely that the VS wouldn't open soon enough on the 465's with that big of engine, it could be that a change in springs, would have been a good test, to see if it picked up anything.
-
Frank a dyno is a dyno.
In my humble opinion you can probably tweek and tune all day long and make small gains on a dyno, but I am uncertain that it translates to the track or the street.
Anyone that makes 550+ hp on the street on street tires and notices a 5hp difference at 6500rpms is a liar :P
You'll notice under the curve smooth transition and low throttle opening responsiveness tho, and this is not something that can be tested on a dyno. (Well maybe one of those fancy inertial dyno type machines)
-
I just went back and looked at the dyno charts.
It looks like the reason the max HP is down, with the 750's, is the right bank has leaned to much.
Then look at the rpm for the torque, the 465 peaks at 250 rpm higher, could that be a indication that the VS, opened a little late?
But overall, in the end, there still wouldn't be a great deal of difference. I don't think there would be 5 lb TQ or 5 HP difference between them.