Redcatfish

Hey guys, I just bought my 98 z28 and boy can I say it's a world of a difference from my old 2v. The car itself has a 01-02 ls6 intake, longtunes headers, cat delete, and x pipe with bullet muffler dumps after the doors. The car also seems to have a off brand slp lid(but looks exactly the same outside and inside) and a upgraded washable filter. 3.73 gears, and a t56 swap.The car also has a dyno tune at Whitehorse racing in dallas. All the mods were done by the previous owner. He claims it put down 300rwhp and 330tq to the wheels. I have a short video of him with it on the dyno, but he didn't show numbers in video. But from what I'm hearing these numbers seem to be low. I'm still learning and I'm just glad to finally be a ls1 owner https://youtu.be/ZLIdx5jA8XE

RPM WS6

iTrader: (3)

Welcome.

I would agree that the dyno numbers are low for an M6 LS1 with LT headers/LS6 intake/lid/ORX & duals plus a dyno tune. You should be at least ~30rwhp higher. 300rwhp (+/- ~10rwhp) is more typical of a stock M6 LS1 car.

Having said that, sometimes dyno numbers don't tell the whole story. You might get a low dyno result, but still run quarter mile trap speeds that are similar to other examples of comparable weight that dyno quite a bit higher. So it's important not to obsessively focus on peak dyno numbers. What's more important is if you have a before and after dyno for those mods, especially if it was on the same dyno/same weather/same operator - at that point you can evaluate the difference to determine what improvement the mods have given you. Doesn't sound like that's the case here, but that would be more useful information than just a peak number.

Or, it might be that your tune is not ideal. Not every tuner is created equal, and sometimes a different dyno tuner can find quite a bit more power in a setup. So a re-tune might be in order, however you have a pretty basic setup so any decent tuner should be able to get it pretty much perfect without a ton of effort. It might also be that other factors have caused a loss of power, such as an engine with a ton of miles, worn/damaged components, the need for some basic maintenance, or perhaps some combo of the above.

Redcatfish

Wow thanks for the great info rpm. I know the car will smoke the tires when I get on it with 315s in the back. When I get a cam I'll head back to Dallas for the tune. I'm thinking of maybe a 224 at 110/112lsa or maybe a 228r/232 112/114 lsa. The car is my daily driver. The car is running basic oil, and im going to swap it out for 0w30 mobile one synthetic. Also today i noticed a vacuum leak in the throttle body in between the hose and the clamps. I refit it and the car isnt droping rpms anymore.Still a complete newbie to the LS engines, but I'm learning quickly!

farmington

iTrader: (14)

that might not be too far out of line if it was tuned on a Mustang dyno. they read about 10% low compared to a dynojet. that would be your missing 30hp.

Docrocket1967

iTrader: (1)

Try getting it retuned and not all dyno's read the same. I would guess it probably is making more than what the dyno said.

RPM WS6

iTrader: (3)

I agree, I was assuming Dynojet with my post above.

Redcatfish

Yeah thanks for the replies. The car is extremely fast compared to my last car(2v) and the car absolutely annihilates the htr 35z 315s with almost brand new tread. Think I could take on a stock 5th gen/5.0 or maybe a sti lightly Modded? Here are a few videos of the car

thatoneguybriz

iTrader: (2)

Too many variables on any given dyno to have a completely analogous comparison of power numbers. Ambient temperature, dyno brand/firmware, tire pressure, correction factors, etc. The key is consistency. If you stick with the same dyno over time, you have a reasonable basis of comparison before and after a given modification.