FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Jim Comet on June 03, 2021, 08:28:47 PM
-
How timing effects my engine or more importantly doesn't effect the cars performance. As many know I have a BP built 416 with his pro port heads, 850 dp, 12.2 to one compression and his baby roller solid cam (265/272@.050 .540/.525 lift) that made 600hp on Jays dyno. My car is a 3500lb 66 Comet with 4.11 gear, 5000 stall and 28 inch slicks. The car runs great 10.75-10.90 @122 in the quarter. My question is, I have changed the timing from 26deg to 32deg trying to either get closer to 10.50 or 11.0 for index racing at my local track. No matter where the timing is, the ET doesn't change. At least until I tried 25deg and had a bog off the line. What are your opinions on why the timing changes do not move the ET? Could it be the efficient combustion chamber? I think my next try will be a throttle stop. Next year I am going to try 29 inch slicks and see what happens. Also no matter what the timing, my 60 FT times are 1.47-1.49. Any thoughts would be appreciated. Thanks, Jim
-
More timing than the layout of your combustion chamber needs will simply not make more power. When I say 'layout' I mean the entirety---the space and shape in the head, the surface of the piston, the locations and sizes of the valves, the placement of the plug, et al.
On the other hand, less timing than is needed will surely make a difference, as you have discovered.
KS
-
Do you know or remember any timing figures when it was on Jay's dyno?
-
I see instances on the dyno all the time where timing changes really don't make a difference. For instance, I may set an engine at 36°, make a pull, read a plug and see that I can take timing out, then do that and not see a change in horsepower. Making a timing change doesn't always mean the engine or car will respond.
-
Similar deal here. Some combinations are just insensitive to timing, while others are very reactive. On some tests I have seen engines where advancing the timing will improve the A/F ratio numbers, making the engine more efficient without significantly changing power. So changing the timing made the engine "better", just not better using the measurement metric we like as hot rodders.
-
How did the trap speed change with timing?
-
All my trap speeds were 121-123 through all 15 runs over three day weekend. Sounds like my best bet may be a throttle stop and adjust it for the 11.0 class. Jim
-
Throttle stops can be a little tricky. Some of my guys use adjustable carb spacers. They act as an adjustable restrictor. You can slow down easily if you need to, no need to adjust driving style. One of my guys can run a 6.90 but regularly runs in a 7.50 class with one. Holds it flat on the floor and drives like normal.
If you want to go a little quicker and aim for running a 10.50 class, I would suggest some different cylinder heads or camshaft. If you're running a 10.80 and want to run a 10.50, you're gonna have to pick up about 60 hp.
-
If you want to go a little quicker and aim for running a 10.50 class, I would suggest some different cylinder heads or camshaft.
So what heads are you suggesting would suddenly pick up ET over Blair's Pro Ports?
Jim, to slow down a bit, Mr. Fotti would simply limit his throttle, and/or add a little ballast to the car. It seemed to work pretty well for him.
-
Just a WAG here, but to get into the 10.50s I think you need to get the 60 ft down. Might need some gear depending where you are on the big end, maybe a different converter, maybe not launch it on the converter, come out a little lower rpm to use the torque multiplication?
Just bench racing, if you have tried it all, pat me on my head and send me to get everyone a hamburger :)
-
If you want to go a little quicker and aim for running a 10.50 class, I would suggest some different cylinder heads or camshaft.
So what heads are you suggesting would suddenly pick up ET over Blair's Pro Ports?
Jim, to slow down a bit, Mr. Fotti would simply limit his throttle, and/or add a little ballast to the car. It seemed to work pretty well for him.
I will back up and clarify my statement. I think a head/cam upgrade would pick him up, but I don't think he's going to get a 10.50 with *just* a head/cam upgrade. Dropping .3 would take around 60 hp, but I don't think he's going to make that up with just the engine alone. I think it would take a head/cam upgrade, along with maybe some converter/chassis/weight work to make up the difference.
As far as a head upgrade, I would try some ported TFS heads and a camshaft to match, or even have Blair go back into the heads that Jim has.
Adding ballast would certainly be another way to slow the car down consistently. Several ways to get to that point.
-
when I was running index with my 289 66 fairlane I had a 12.50 setup with a 780 carb, open headers and no added weight on good air days, if bad air, I went with my 13.00 set up, 650 carb, mufflers, and added weight as necessary to get dialed in. never changed timing. worked well for me for years.
-
Do you happen to have a different torque converter to try? I’m wondering what the rpm is through the lights also?
-
Your 4:11 gear is not your friend with 3500# car. Try a 4.44, or 4.57. Joe-JDC
-
Throttle stops can be a little tricky. Some of my guys use adjustable carb spacers. They act as an adjustable restrictor. You can slow down easily if you need to, no need to adjust driving style. One of my guys can run a 6.90 but regularly runs in a 7.50 class with one. Holds it flat on the floor and drives like normal.
There is a trick some use with throttle stops that is hinted at here - setting the stop to be ON for the entire run. Some are finding more consistency by having the stop just be set to partially close and stay there. Like the adjustable restrictor. Should be able to quickly build a database of stop settings vs air conditions for running against an index.
I know a lot of the X.90 classes use stops, same reason as some bracket racers. Some of the fast bracket dragsters (and at least one fairly fast big door car that dials 7.0x in Super Pro) use the stop to make a big run at the stripe to make it hard to judge. 8.90 Super Comp running 180+ - yea, that's what. Top Dragster people use them to not get DQ'd for running quicker than 6.10 at 220+ MPH LOL.
-
Your 4:11 gear is not your friend with 3500# car. Try a 4.44, or 4.57. Joe-JDC
Right here ^
and I will add the car is not happy with your set up. 600hp should have you in the low 1.40's to high 1.30's 60ft times. With the power it should be running low 10's.
What type of trans? Any tire spin? How do you leave the line? what RPM shifting and what RPM at finish line?
I think Blair has a couple of different PP programs with one being a street version, I wouldn't mess with a head & cam change if it's already making 600hp.
-
If you want to go a little quicker and aim for running a 10.50 class, I would suggest some different cylinder heads or camshaft.
So what heads are you suggesting would suddenly pick up ET over Blair's Pro Ports?
As far as a head upgrade, I would try some ported TFS heads and a camshaft to match, or even have Blair go back into the heads that Jim has.
As Mike mentioned, there are a couple versions of these heads. The street exhaust and race exhaust. I believe Mr Jim here, has the race if memory serves correctly. I believe I heard that the same heads as Jim's on a different combo made 800hp or just north. I don't think the heads are the "cork". .500" lift on a race-only setup is leaving a little power potential with the heads being capable. I know reliability was in mind originally for the setup, though. I have the street version. They work just fine on an old dump truck engine.
-
Are you saying TFS heads are an upgrade to Blairs pro Ports heads?
There are many incantations of Blairs Pro-Port heads. From mild to wild.
I haven't seen any TFS heads on 900+ HP builds. Blairs Pro-Ports - yes.
I would also think the OP could change his mild low lift cam to something more aggressive to pick up 60 HP.
-
Are you saying TFS heads are an upgrade to Blairs pro Ports heads?
There are many incantations of Blairs Pro-Port heads. From mild to wild.
I haven't seen any TFS heads on 900+ HP builds. Blairs Pro-Ports - yes.
I would also think the OP could change his mild low lift cam to something more aggressive to pick up 60 HP.
Yes, I understand there are many incantations of Blair's Pro-Port heads, so yes, I would say that there would be some incantations where a TFS or a ported TFS head would be better. I think this is one of them. I also agree that a cam swap would pick up some horsepower. Maybe not 60, but between some head work and a cam swap, I think it could be bumped up.
-
In my mind, 600 HP and 121 MPH does not make sense. It`s been many years since I raced a car with an automatic, but I know many people who found major improvements with different torque convertors. A racer that I know switched from a TCI convertor, that TCI built, supposedly after he told them his combination, to an ATI. Not only did the new convertor give him 6 MPH, but despite going much faster, it did so at lower RPM (less slippage), so he installed steeper gears, and picked up even more performance. What sort of finish line RPM are you turning at 121 MPH?
-
Rory I am in that 121 mph slot and I guess that my motor was making approximately 540 -550 horse in a 3500 lb car with me in it. I’m don’t think my motor is timing sensitive as far as speed wise. But I do notice how cool it runs when it’s advanced. I did a lot of tuning to get my times down and timing did the least. Jim were you advised to get a 5000 stall converter it just seems hi. I would just think 35 to 3800.
-
My converter is an ATI spec'd by Blair for my car. I am not sure what the stall is exactly as I don't have a data recorder and am pretty busy during launch. I should get or borrow a go pro to monitor my instrumentation during my runs and I could have a more accurate answer. I am not disappointed in the cars performance, I just want to move it closer to either 10.50 or 11.00 for my index racing class at BIR. ONE other thing is my rear gear ratio. While I am running 4.11 rear ratio, I do have the low gear set in my C6 with the 2.72 first gear. Would switching to a 4.56 gear be too low and force a really early 1st gear shift? Jim
-
Well if Blair spec it then he knows his setup
-
Brent. Incantations of Blair's heads would imply supernatural powers, which some may attribute to them, but I am not sure that Blair would support.
Sorry just could not let that one slip by.. ;D I think everyone knew what you meant to say
-
Brent. Incantations of Blair's heads would imply supernatural powers, which some may attribute to them, but I am not sure that Blair would support.
Sorry just could not let that one slip by.. ;D I think everyone knew what you meant to say
Haha, that’s not a word I would normally use but was using Perry’s phrase when I quoted him and replied to him. I’m not smart enough to use that word on my own accord.
-
My converter is an ATI spec'd by Blair for my car. I am not sure what the stall is exactly as I don't have a data recorder and am pretty busy during launch. I should get or borrow a go pro to monitor my instrumentation during my runs and I could have a more accurate answer. I am not disappointed in the cars performance, I just want to move it closer to either 10.50 or 11.00 for my index racing class at BIR. ONE other thing is my rear gear ratio. While I am running 4.11 rear ratio, I do have the low gear set in my C6 with the 2.72 first gear. Would switching to a 4.56 gear be too low and force a really early 1st gear shift? Jim
You might be able to evaluate the steeper gear option with a shorter tire. See if you have a buddy that could lend you some 26" slicks or pick up a set for cheap somehow? Assuming good traction you get some sense before committing to a gear swap. On the flipside if you do go 4.56 and it's too steep the 29" might get you out of a jam. Probably should run the math on the dimensions first though.
-
My converter is an ATI spec'd by Blair for my car. I am not sure what the stall is exactly as I don't have a data recorder and am pretty busy during launch. I should get or borrow a go pro to monitor my instrumentation during my runs and I could have a more accurate answer. I am not disappointed in the cars performance, I just want to move it closer to either 10.50 or 11.00 for my index racing class at BIR. ONE other thing is my rear gear ratio. While I am running 4.11 rear ratio, I do have the low gear set in my C6 with the 2.72 first gear. Would switching to a 4.56 gear be too low and force a really early 1st gear shift? Jim
Have you discussed any of this with Blair?
I am sure he would have a few suggestions to get you to 10.50's.
He does know his way around FE's.
I am sure he would appreciate being in the loop.
I recall an engine masters competition where an all iron Blair Patric 390FE made 596 HP @7100 rpm. (Using C4AE-6090G heads)
I assume that EM dyno numbers are heavily scritinized.
https://www.hotrod.com/articles/iron-ford-390-fe-makes-596-hp-using-stock-heads/
-
I have been talking to and am working with Blair. I am going to try a couple of things to see if I can move closer to the 10.50 index. As a racer my natural inclination is to gravitate to the faster ET. But if my changes don't work, I am fine with the 11.0 class. Jim
-
Quite a problem you have there Jim, high 10s and 1.47 60’ times, lol. I think I mentioned it in an earlier thread that a data logger would answer a lot of questions. Since you are campaigning an FE you are already used to stimulating the economy.
I came to this thread late. Usually check to see if anything has been added to the racing tab and this thread would have fit right in there IMO.
Please keep us posted.