dci67

I agree, it kind of shows that the stock LS7 heads pretty much max the plastic intake. The results are still great, especially considering their heads cost less than stock. They would probably show more gain if tested back to back with a sheet metal.

I would like to see what it would do on 93 octane instead of 113 to show what we would really get in street trim. Who knows how much it would drop, its does have street compression at 11.8 so I would like to think not a huge amount, but I don't know how to even estimate that.

The Alchemist

iTrader: (19)

Actually, it would probably make more power on 93 than the 113. You always want to run as low of an octane without getting knock. As the octane rating goes up, the amount of energy decreases, which is one of the reasons octane goes up. Octane is a measurement of resistance to auto ignition, in loose terms. The higher the octane, the less thermal energy available.

I wouldn't doubt that it would make a solid 7-10 more horsepower with 93.

dci67

I guess that would depend on how they had it tuned as well. I see your point if it was a 93 octane tune and then all they did is put 113 in it, but if they tuned it for 113 I'm sure they would have to back off the timing for 93. Anyhow, just seems l like a lot of variables to me, I wish they tested with 93 they we would not have to speculate.

-Joseph-

iTrader: (12)

I believe these runs were 28* of timing. It made the most power at 26*, but thats not shown in these dyno runs, but was done later with other cams. We could have made much more if this was more of a race setup with more compression, but this motor was a in-stock motor that is going to a customer next week for a GTO.

I do have a similiar setup scheduled for install, but it probably won't be done until the middle of January with how busy we have been.

Anyway just thought I'd throw another post in before going skiing. Have a great weekend guys!

dci67

Thanks. Let us know what it does at the tire in that GTO. I'm seriously considering a big cube upgrade. I want to stay with an alum block (427 or 440), but this gives some good perspective.

WickEdSix98

iTrader: (4)

Does the motor make the most power with the brake specifics that low? They show scary lean. Maybe a fuel injected engine acts different than carbureted engines on a dyno though.

jermzz

iTrader: (18)

I think he's saying to run that octane you need higher compression. You always want to run the lowest octane you can without detonation. 11.8:1 can run 91 without detonating. 12.5:1 however you can not. Minimum you can run is 100. Running high octane in a car that doesn't need it will make you lose power. Thats how I understand it anyway.

JakeFusion

iTrader: (7)

Just as an FYI, TSP ran similar conditions with their 418cid L92 headed engine that made 640HP on the engine dyno with those same 1-7/8" headers.

In a Camaro that 418 L92 made 560rwhp with 1-3/4" headers and full street trim. So if you figure the variables were about the same for the engine dyno, then you can count on losing probably around 80HP. I lost around 70HP in my Vette - engine dyno to chassis dyno, so I figure that's pretty close.

720HP - 80HP is still a god awful lot. I'm not sure it'd pull 640rwhp... but ported LS7 heads with big cams have made 600-615 with 427cid. Add another 25+ cid and it could add another 15-25rwhp. In street trim it's probably a solid 620rwhp.

maddboost

iTrader: (11)

Yes but the PRC heads are only a few hundred dollars more than the GM LS7 heads. Lots of guys spend hundreds of dollars for less HP/TQ gains.

Great work TSP.

ScottyRocket

What's up with the oil pressure dropping off on the initial run? bad sensor or pump?

Jason 98 TA

iTrader: (4)

This post completely amazes me.... Do you understand what your saying? Your saying your surprised that we were able to build a cnc ported head to replace a already cnc ported head with all the same components & pickup ONLY 27hp? That post completely surprises me!

Here's what you get: 27 hp over the stock ALREADY CNC PORTED HEADS for less cost than a brand new GM CNC LS7 Cylinder Head!

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Guys the engine was run on 100 octane, but it will be in a 93 octane GTO very shortly.

We've had several dyno tests showing 30rwhp gains on LS7 Z06 cars with no other changes but the heads & a little decking.

-Joseph-

iTrader: (12)

I posted earlier that that run had a vacuum pump on it then (-15), but we had problems keeping the belt on with the later pulls.

Jason 98 TA

iTrader: (4)

The Alchemist

iTrader: (19)

Sorry to **** you off. I didn't realize the factory LS7 head was a cnc ported peice and I didn't realize that what you were offering was less than the factory heads.

But still. It's not the size gains like going from an ls1 factory cast peice to a custom cnc'd head that you see 50+ horsepower.

I wasnt' knocking yours, just saying how well the factory heads flowed considering the larger cam and headers ect. It tells me that the factory ls7 heads aren't the biggest restriction in the factory ls7.

The Alchemist

iTrader: (19)

Plus, I understand that you say people are picking up 30hp just swapping heads, but how much of a gain are they getting from doing a different cam? It's an honest question, that I don't know the answer to. Everything I've heard was the ls7 was undercammed from the factory and people were seeing pretty big gains with just a cam and header swap.

Jason 98 TA

iTrader: (4)

Oh I got ya!!! The ls7 picks up huge power with cam & head swaps thats for sure!!

N4cer

iTrader: (11)

It's always a nicer running car if done with heads instead of cam, when comparing same HP numbers.

HTMtrSprt

Actually, octane has NOTHING to do with a fuel's BTU content so saying a lower octane fuel has more energy potential is not true.

HTMtrSprt

And..... brake specific fuel consumption has nothing to do with air/fuel ratio, it is simply a measure of how much fuel it takes to produce the engine's horsepower.

fastvet

iTrader: (2)

That is very impressive! I would like to here that engine at an idle.

Jason, What was the lobe separation on that cam that produced those numbers? And what was the lift on it too? I would really like to know.

Thanks,
Jesse