hammertime

They are a great intake with a carb and a good choice for anything but with injection there isnt any gains over any other decent brand intake.

Let us know how everything turns out when they redyno it.

kod99

Ok. The engine is done and I put the Sniper manifold on it. I took it to the dyno (Super-flo 902) on Friday and made 23 pulls on it. Made 3 pulls with a 1150 Holley Dominator carb on C16 first to seat the rings. Then I installed the Ron's terminator and switched to alcohol.

On alcohol, the engine would nose over on the horsepower curve at about 6000 to 6300 RPM.

The final configurations that worked, and didn't nose, although the horsepower curves did flatten out, over were:

39 nozzles - 82 pill - 31 degrees advanced timing
922 HP at 6400 RPM
829 ft# torque at 5200 RPM

41 nozzles - 88 pill - 33 degrees advanced timing
925 HP at 6400 RPM
833 ft# torque at 5200 RPM

Fuel pressure was 68 - 70 psi. I was using a 1/2 Enderle belt drive pump. I had it tested and it fowed at 5.5 GPM.

I did try one hit with the high speed bypass installed and set to 63 psi, but it didn't seem to help stop the nosing over.

The maximum RPM the engine would reach was 6500. I can't figure out why. Dirty air in the dyno room? The exhaust evac system was not sealed that well. The headers were dumping into 6" flex hoses which were exhausted, by a fan, to the outside of the building.

The vacuum pump could not keep up with the crankcase pressure. As the RPM came up, the crankcase would go from 12" of vacuum to 22 psi of pressure. I blew a hole in both the intake and pan gaskets (The Right Stuff). The richer the engine was, the higher the crankcase pressure. I am going to change the drive pump pulley to spin the vacuum pump at 75% instead of 50% of the crank. I hope this helps the crankcase pressure problem.

Another oddity is that with the 1150 carb on race gas, the air flow was 1148 cfm at 6500 RPM. With the 2100 cfm Terminator on alcohol, the airflow was only 1074 cfm at 6500 RPM.

I drained the oil after the dyno run and it wasn't very milky at all.

An input would be appreciated.

ccperf721p

The airflow drop on methanol is caused by the volume of fuel in the runner and is normal.

Did you get any air/fuel ratio data or exhaust temps?

Do you have a pill in the high speed? What size?

zipper06

I'll weigh in at the risk of being critised. You haven't stated (that i have read) what size headers you have, IMO you have to have atleast 2 1/4" to 2 3/8" headers on an engine that size and 4" to 4.5" collector. That would cause the 6500 RPM limit also the evac system on the dyno could effect the vacuum reading at 6500. Ofcouse the dyno does not show what is the real effects at the track. There's 3 or 4 things that could cause it to not run above 6500 RPM. "1" valve springs with the size valves you are running needs to have well over 250lbs. I run 300LBS on 2.140 Titatium on a 434" motor, and i'm sure your's are 2.250 or bigger. I don't know what size cam you have but anything over .750 it should run 7500 RPM's with ease. What concerns me most is that the carb flowed more intake cfm than the Injection. That to me tells me that the exhaust couldn't get out. INO if it can't get out (headers) it can't flow IE: equals high oil pan pressure. A vacuum pump should run 18 to 20 inches of vacuum, anything more that that will dry up the cylinder walls and cause schuffing of the cylinder walls. At no time should it turn to pressure in the oil pan. Again the dyno evac system is not the same as a real run down the track.

These are just my opinion based on previous experience and by no means should it be taken as the cure to your problems.



Zip.

kod99

No air/fuel ratio data.
The exhaust temp was about 1150 - 1200 on the good passes.

I had a 70 pill in the high speed by-pass and set it to full release at 65 psi. The problem was it starts opening at about 40 psi.

kod99

You won't get any criticism from me zipper. I appreciate all the info anyone gives me.

I run 2 1/4" to 2 3/8" stepped Dynatech down-swept headers with 4" collectors. Dart Pro2 CNC heads with 2.33 intake and 1.88 exhaust valves. The spring pressures are 300 pounds on seat and 850 pounds open. It has a Comp Cams custom grind cam with intake lift of 0.846 and exhaust lift of 0.826.

ccperf721p

Did the engine go past 6500 with the carb on it?

Use cracking pressure as the base for your high speed.

zipper06

X2--Use cracking pressure as the base for your high speed.

The exhaust temp. sounds pretty close

After looking at this with a clear head. Get rid of the pressure in the oil pan and the RPM's will come. It's like dynamics, EX: lock your fingers together and pull with either arm, resisting with the other. The stronger arm will win. Same thing with you engine, the top side wins but not without resistence. I don't know the vacuum system you have but if it started out with 12 inches vacuum and ended up at 20/25 lbs. pressure in the pan before it blew the intake gasket, there are some serious issues with the collection system, being plugged or a breather problem plugging up or filling up. i sure with you would have tried header evac system on the dyno. I also think you have another 50 HP once you get rid of pressure in the oil pan, and as many RPM's as you want to run.

JMO.



Zip.

kod99

I used to run a header evac system and I just put the vacuum pump on the engine this year. Shouldn't the vacuum pump draw more air out of the crankcase than the evac system?
When I get to the track, I will disconnect the vac pump and hook the evac back up and see what happens.
Thanks for the input zipper.

kod99

The three pulls I made with the carb and gas were not full hits. Just went to 6000 RPM.