I'm sorry for this not being TPI related, but when I went back to carb from TPI I promised dyno runs, and I'm here to deliver. Well, truthfully I am not really that thrilled with my dyno results, but the operator was pretty tickled with them. He always has problems with MSD setup messing with the tach readings, and he can usually hook up his photo tach to correct it. Well, he got the photo tach to work, but for whatever reason, under WOT, the tach would not work. The tach is needed to get accurate TQ
numbers, so I'll have to wait until next time for those. Horsepower was fair at 334 at 5700. The car is rich across the board, but it turns out we did not have the drill bits small enough to drill out the air bleeds, so that will happen next time(in a couple weeks). He figures getting the air fuel right on
will net me about very low 340s. The most disturbing thing was that power was falling off at 5750 already. With the XR-294 this should not be happening. We both agreed that this motor is a perfect candidate for an AFR Hydra Rev. The motor lost over 30 HP from 5800 to 7200. Noteworthy is that the operator was
very impressed with the runs, and said that next to nothing N/A runs over 300 to the wheels on his dyno. He has dyno'ed tons of LS1 cars, and typical 6 speeds are running about 300 to the wheels, and higher mileage ones have ran as much as 305. A modified LS1 with headers and T.B, and a bunch of other
stuff ran 327, I saw the chart on that one, and the operator said the guy was pretty smoked about it. Well, thats about it, so assuming a 20% drivetrain loss(which he confirmed, he said 13 to 15 for manuals, and 18 to 22 on autos) my motor has about 400 FWHP. Not overly impressive in my book compared to
what I was hoping for(and promised), but its a starting point. If anyone would be interested, I can have the dyno slips scanned. I'll keep you all updated.

 

Is that a cutlass?

 

Its a 79 Monte. That picture was back before it was painted, now its Viper GTS blue.

 

What are your engine specs? Parts? Cam? Exhaust?

Thanks!

 

I agree that your setup is leaving something on the table. If power is faliing off at 5700, look at your valvesprings. I have set up many sets of heads on hydraulic roller motors. If the springs are right, you should be able to spin the motor to 6500. Go with Comp 987-16 springs and titanium retainers. This will get you the rpm you're looking for.

www.geocities.com/dzperf

 

First off 88TPI406GTA, my engine goes as follows:
89 355
Edelbrock E-Tec 200 heads
1.5 Crane Golds
Edelbrock RPM air gap vortec intake
Mighty Demon 750
Comp XR294-HR roller cam
SRP forged pistons
Eagle 6 inch rods
Eagle crank
Motor is 10.3 to 1
Full MSD ignition
1 3/4 inch headers
2.5 mandrel true duals with 3 chamber flowmasters
TH-350 with B&M 3600 stall <--- Total crap, still not locked up at 7200 RPM.

Now HiTech5,
Do you think that the Hydra Rev could work for what I am looking for? There is just something inside me that doesnt want to mess with these heads seeing as they are brand new. All thoughts are greatly appreciated because I need more power!!

 

If you're starting to loose power at 5700 with that combination, the valve springs are not matched to the cam. Did the springs come with the heads? It's not that difficult to change the springs with the heads on the motor. The Comp 987-16 springs are 1.437" in diameter and will fit your heads without a problem. What you will need to do the job is:
1. Air Compressor.
2. Valve spring compressor.
3. Fitting that screws into spark plug hole.
You can change the springs without needing to pull the intake manifold.

 

The springs that I am using are the springs that came on the heads. So you feel that changing the valve springs would be more worthwile than the Hydra Rev? I am up for whatever solution gets me a few more RPMs of power up top. With this converter, and the way this thing revs, its always bouncing off 7000.

 

The springs are the place to start. I'm sure that the springs that come with the heads are not enough to handle the aggressive ramp of an Extreme Energy lobe. Changing the springs is not that difficult. A first timer could do it in less than 4 hours.

 

That is a pretty healthy cam. I would agree that valve springs and/or the Hydra Rev are things to look at to increase your top end.

Good luck on getting the final combo dialed in right....

 

could you post, so I could see the torque curve? what are the cam specs?

Is that a stock balancer I see?

 

Hopefully that dyno graph comes up. The torque is funky because of the tach being goofy on the dyno. The stock balancer was used until the Pro Race arrived... I figured someone would bite on that Cam specs are .540 .562, 242 248, 110 LSA. I spoke to a fella at Comp Cams and he told me my springs are a joke for the cam. Do you think an either or for Hydra Rev or valve springs would be OK, or would both be neccessary? These are pricey trials, and peoples input is greatly appreciated. Thanks

 

Oh jeez, the stock springs on there were only rated to like .510 or something I think, maybe I'm mistaken...

 

Actually Ray, the springs are rated to 570 or 575 lift. The problem is that they are a single spring, and they just cant handle the high RPM load from the hydraulic roller. I'll have to re-scan my dyno sheets, they were too big to post here

 

What spring did Comp Cam recommend for your application?

I'm feeling that you'll need a spring with a seat pressure of 130-140# and an open pressure at max lift of 340-350#.

 

HiTech, Comp suggested the same springs as you did. The 987-16's. I spoke to Edelbrock today, and the tech absolutely stood behind the springs on the E-Tec heads, and said the springs are not my problem. I got out my paperwork for the heads, and surprisingly the numbers are 120# at the seat, and 340# at .600 lift, with a maximum valve lift of 600. Hmm... its hard to believe either company, because the both have interest in their own products. What do you think?

 

I had a set of Edelbrock RPM heads on my 383. The cam I had was a Comp XE 230/236. I left the stock Edelbrock springs on because of what they were rated for lift and pressure. They were ok for a very short time but quickly showed signs of weakness.

I could not tell at first but my buddies were telling me that the car sounded like it was hitting a rev limiter. It turned out to be valve float. I changed the springs to Comp 987-16 and went with the Titanium retainers. It felt like a new motor. No BS!

 

i suggest you get one of those valve springs yanked off the etec heads and check to see what its really at for seat pressures...

i'd be willing to bet that its close to not being stiff enough. Big cams requier big seat pressure... I am having the same issue with the springs in my 305 build up- i get to 5000 and everytime its a rev limiter- i know its the springs, just havent gotten the motivation to get some better ones on there.


Steve