crazyjoe

Ok, heres the long and short: last dyno run was 259.xx fwhp/270.xx fwtq, swapped to an ls1 intake and re-dynoed, and saw 257.xx hp/277.xx tq. I lost 2 hp and gained 7 tq, less than impressive. The air/fuel was identical to the last dyno run, so the tune cant be off that much if any at all. Thoughts?

Bryan921SS

Did you adjust your shift points?

I think the LS1 manifold gives the most gains up top.

Could also be restrictive exhaust....the more air you cram in the more air you need to get out.

crazyjoe

Shift points were already adjusted, 6200ish rpm pulls in 2nd gear.

CenTexSS

iTrader: (2)

Did you retune also?

nmp0098

If you didn't retune, then you can still have issues even if the LTFTs are keeping your fueling in line. I wouldn't be surprised if the MAF curve was thrown off due to the plumbing changes you had to make, and possibly MAF clocking. Depending on how much you are trimming, you can can really be off in your cylinder load calcs (g/cyl), which heavily influences spark timing. You could be knocking all over the place right now, or belching power out of the exhaust because you don't have enough advance. When I first put the LS6 intake manifold on my car it felt like someone put an extra spring under the pedal. A simple MAF adjustment turned the car back into a tire roaster. Unless you find a tuner who gets your VE dialed in, you'll never get great transient behavior though (tip-in especially).

There's also a lot that can go wrong with a dyno too. Unless you did five pulls each time, took an average, and corrected for all of the variability created by the different ambient conditions, you can't read too much into dyno results. Others will disagree, but I see a chassis dyno exclusively as a tuning tool. It's great for getting the air mass models correct (especially low RPM/high load data) and finding the correct advance for MBT. An SAE certified engine dyno is a different animal altogether, and it is the only tool I would trust to accurately measure the power difference between two different combinations. But, you have to do the best with what you have. That's why I've never been in a hurry to get my car on the dyno. I'd only want to do spark tuning and compare torque curves at different commanded AFR values, and I keep changing parts that have a significant impact both of those.

Sittingmongoose

iTrader: (1)

What supporting mods do you have? and like nmp said. Dynos are just stick measuring tools. It doesnt really matter what it says, it matters what it runs. But it sounds to me that your tune isnt right.

crazyjoe

Supporting mods: fenderwell intake, doug thorleys, no cat, stock catback/mufflers.

I totally agree with you guys that the dyno is simply a tool, the numbers themselves dont bother me, what bothers me is that I lost hp, LOST!!!

I'm gonna have my tuner take another look at the tune and see if anything looks odd, I sure the hell hope something is outta whack to make me feel better about this swap. I'll keep this post updated as soon as he gets some free time to re-examine it. Thanks fellas.

Joe.

Rossko85

iTrader: (11)

You can go and find a way to put a big LSx intake from FAST on your car and if not tuned for the change in air induction...then yes...you will, or could LOOSE power...LOL...funny thing I know...but its not always about the bigger and better part...LOL..the tune can make the smallest things perform big! LOL so to speak...you need to not count out ALL of the numbers though...Its not all about WHP man...you still had GAINS...it was just in your torque curve...

So, like you said..get with the tuner...play a bit and I bet you would be suprised...You will get your numbers...just keep and open mind, think outside the box and see where your upgrade goes in different parts of the curve...again, its not all about 1 single number...a gain is a gain, and loss is a loss right?

Good man!

DavidGXP

iTrader: (14)

When I put on my LS1 intake it was night and day. The TQ was insane..
I used the Diablosport non DOD 91 octane tune to get it running and had no issues.
I find it pretty much impossible to lose power with this intake. The runners are longer and the Inlet is a true 76mm compared to the stock LS4 pile of crap.

I bet your tune is way off... Never get dyno'd till your tuned or else your just wasting our money

Sittingmongoose

iTrader: (1)

ya something is up. Only thing i can think of is that either ur tune is way off or your exhaust is choking your car.

Panther427

What fuel do you run?

Sittingmongoose

iTrader: (1)

me? 93 octane

Panther427

sorry OP maybe he had bad fuel. or wrong octane when he hit the dyno.. like in the early days people having problem with shell (i think) gas

DavidGXP

iTrader: (14)

Get re-tuned and go back. Then we'll try to figure out whats up.

crazyjoe

Thats the plan, re-tune and hit it again, and i always run at least 91 octane.

Sittingmongoose

iTrader: (1)

ya run 93 octane and dont use shell. I have dyno results from shell vs other providers and there is a big difference