519" SOHC Build

[machoneman]

I'd agree with your quote that the injector butterflies are too small for the engine's CID and head flow.  Adding larger butterflies would increase top end hp but hurt torque...it's your call but getting a larger i.d. could get pricey. When one looks at the now very old Algon F.I. setups for the FE the butterflies were tiny compared to your setup, although early and essentially passenger car FE head flow rates (b/4 high risers, tunnel ports, etc.) rpm levels and 390-427 CID's didn't need any more I.D. Would be cool to pursue much larger injectors but hey, it's not my money       

Very interesting data indeed seing them laid out like that.  The two engines are not directly comparable - significant differences in heads and cam, as well as competitive intent, dyno brand & cell.  But as Bill noted you can really see the wave tuning impact of the stacks as compared to the plenum intake.

Some of your prior testing ha shown significant gains in midrange with the stacks & that was what I was looking for.  I have a feeling that if you played with diameters and lengths you'd see that big tuning wave again - just seeing how it "comes on" here.  Probably very application dependent.

I agree, after thinking about this a little I'm sure that the large stack diameter and large throttle butterfly diameter of the Hilborn setup is hurting low end torque production.  On the other hand, it is needed for top end power, and in fact I've had a few knowledgeable people tell me that the injector butterflies are really too small for this engine.  I guess this is why you don't see the Hilborn style setups on a lot of drag cars. 

On the other hand, they sure look cool 

[jayb]

Its not so much about the cost as it is about availability.  There isn't a set of injectors available for the engine with bigger throttle bodies, so I would have to build my own.  Kinda figured if I was going to go through all that trouble, I'd be better of building a conventional sheet metal intake.

[cammerfe]

Jay understand I know little to nothing.....
Would running 2 different length stacks maybe flatten the torque curve?
My Sprint Car racing cousin does that on a slick track with a SBC says it widens the torque curve.

I believe you'll find that the 'two different stack lengths' phenomenon you sometimes see on a BBC is due to the 'good' and 'bad' intake runners that are found on the 'rat' motor. However, some NASCAR engine builders have experimented with different (calculated) lengths on their headers---with good results---and it might well be that multiple stack lengths would offer similar results!

KS

[machoneman]

Actually, there are much larger injectors available, although they would not have the look of the individual stacks. Using one of these injectors (or a similar one) on that custom sheetmetal EFI intake would be a snap.I only wonder if they might pass too much air when closed at idle since they weren't designed for gasoline engines.   

   http://www.dmpeinc.com/superchargers/index.php/other-components/injector-hats.html?mode=list

Perhaps a couple of throttle bodies merely for air handling from Ron's would work better as he has a large range of high cfm 4-hole bodies. 

http://ronsfuel.com/efi_throttlebodies.cfm

Its not so much about the cost as it is about availability.  There isn't a set of injectors available for the engine with bigger throttle bodies, so I would have to build my own.  Kinda figured if I was going to go through all that trouble, I'd be better of building a conventional sheet metal intake.

[jayb]

I was talking about SOHC specific injectors.  Once you go to a custom intake there are no limits, but the issue is building the custom intake.  No time for that at the moment...

[Cyclone03]

Jay understand I know little to nothing.....
Would running 2 different length stacks maybe flatten the torque curve?
My Sprint Car racing cousin does that on a slick track with a SBC says it widens the torque curve.

I believe you'll find that the 'two different stack lengths' phenomenon you sometimes see on a BBC is due to the 'good' and 'bad' intake runners that are found on the 'rat' motor. However, some NASCAR engine builders have experimented with different (calculated) lengths on their headers---with good results---and it might well be that multiple stack lengths would offer similar results!

KS

I knew that about BBC, this is a SBC I have no clue power wise what it does but it "softens" the hit to the tires so it laps faster on slick tracks.

[jayb]

With the engine back off the dyno I pulled the pan tonight, and then removed the oil pump to find the source of my high pressure.  After punching a hole in the soft plug and removing it with a screw, I immediately discovered the problem.  The pump spring had a shim behind it.  This is the shim that Precision Oil Pumps includes with their pumps, in case you want to run a higher oil pressure.  Apparently I had installed this shim in the pump when I put the motor together the last time in 2008.  I had completely forgotten about it.  Back then I was experimenting with some light weight synthetic oil, and had installed the shim to boost the oil pressure.  It never occurred to me when I was putting the engine together this time that I had done that.  Oops 

Well, at least the problem is resolved now.  Just gotta put the pan back on and slam the engine in the Galaxie...

[Joe-jdc]

So, you really are human after all??   Good luck with the Galaxie.  Joe-JDC.

[fetorino]

Stop goofing around with the daily driver and get back to work on that 545 high riser.

[jayb]

LOL!  I'm kind of anxious for that one myself.  Pistons should be back from coating in 2-3 weeks, then a week for balancing, then assembly and dyno.  Look for the high riser towards the middle or end of May...

[fetorino]

LOL!  I'm kind of anxious for that one myself.  Pistons should be back from coating in 2-3 weeks, then a week for balancing, then assembly and dyno.  Look for the high riser towards the middle or end of May...

Maybe my Tunnelport can make it a back to back wedge dyno weekend.  It should be together by the end of May.

My hp target is a lot lower than yours but it will be interesting to see where it ends up.

[jayb]

That would be cool...

[ScotiaFE]

How much oil pressure would you like to see on your small SOHC?

I have a POP Melling M-57AHV and have the heavy spring to put in it.
I plan on running this pump in my Genesis build.
I'm thinking it will make about 110 psi.
Using a 10w30 oil.
To much?

[jayb]

Oil pressure is somewhat overrated, IMHO.  The real oil pressure is generated inside the bearing/crankpin interface; as long as you have enough pressure to supply oil to the bearing clearance area at the rate that it is leaving, you have enough oil pressure.

I like to see at least 15 psi at idle, and 60-70 psi going down the road at 3000 RPM.  If it goes over 90 psi going down the track, I'm thinking its a little high.

[cdmbill2]

For optimum oiling the question isn't pressure, its adequate volume at every point where the oil film or splash lubrication/oil cooling is required. The pressure requirement derives from what is needed to maintain the oil film at the bearings, lifters, rockers etc. throughout the loaded RPM range. Extra pressure is just wasted horsepower and a system that sees pressure out side the norms for typical similar engine design with simialr clearances indicates an artificial restriction starting with Jay's shim in the pressure relief valve, but commonly in misaligned bearing shells, rocker shafts, lifter to bore relationships or casting issues.

Its the volume requirements that have to be managed when looser clearnaces, spring oilers, piston oilers or vacuum pumps among others are added to the build requirements. This is oil pump voulme output, not system capacity. I like larger over all system capacity as a way to keep temps under control and allow for adeqaute top end oil supply with appropriate managment of oil return and windage. This has become of big part of making big cams with solid rollers survive street driving and racing such as we do at Drag Week.

The real FE experts here can weigh in but 110 sounds way high to my thinking.