Hey everyone, I have a base C6 corvette ls2 block. So far I have dome longtube headers with a cat-less mid pipe, Cold air intake and a dyne tune. Im experiencing a loss in low end torque which I don't like. Is this related to back pressure from having no cats at all? Or what could be a reason for this. The headers I'm running are 1 7/8 to 2.5" axle back again no cats. I also have a Vitesse throttle controller could this have anything to do with it?

Furthermore looking into the next perforce upgrades for my car, how much benefit would I receive from a intake manifold such as an MSD ported manifold and a re-tune. Im shying away from a cam as of now because of reliability. What other performance upgrades would benefit the ls2. Thanks guys!!!!

 

Headers cause the car to run leaner (they scavenge more exhaust out of the cylinders and how they produce more HP ) and you need to retune the car so the AFR is not running on the lean side during WOT instead. Also, some CAI systems cause turbulence at the Maf sensor so it not reading correctly, and that too needs to be adjust in the tune as well.


So no, its not a lack of back pressure the problem, but the fact that you have moded the engine enough that it now needs to be re-tuned correctly instead.

As for intake manifold, the OEM LS2 sucks due to the way it was produced (sonic welded from pieces), and replacing it with Fast intake will be the ticket. Not only will you pick up more top end HP, but more HP across the entire RPM band as well.

So, the way all this adds up, the LS2 makes 411HP stock. if you just tune a stock LS2, you end up with about 426hp isntead.
Now with headers and fast intake added to the math with tune, they will pick up another 35~40 Hp, ending up with the motor making around 465hp with correct tune.
The CAI does not add power, but instead prevents the intake from sucking in hotter air that will cause the motor to pull timing, and cause a loss of HP isntead.

Amount of timing pull per air temp that the motor is drawing in, and the air temp sensor is in the MAF.
Attachment 48334173

As for since you stated tune, what type, since if it was a canned tuned, bank that it did not cover either the headers, nor adjusting for the Maf less than ideal reading, and what it causing the problem with that tune isntead.

If you have the tune file, then link it, or if you have a Dyno print out with AFR and spark advance on it, then post it instead.

 

Get a tune

Clif

 

Where is this 411 hp idea In the ls2 coming from?

 

Why did you install 2-1/2" mid pipes? Shoulda gone w/ 3"!

 

You will lose low end torque with your 1 7/8" headers.....1 3/4" is what you need unless you plan on adding boost in the future....Take that vitesse thing off and toss it are sell it.

 

Its the real ASE power that the LS2 makes and not the de-rated HP number that GM released in 2005, so they could move the last off the new C5 z06's only making 405hp off the lots in 2005 isntead.

 

My midpipe is 3" into a 2.5" axleback

 

 

You do not need to worry about reliability from installing a cam - go to PatG and get a custom made cam to your specifications when you fill out the answer sheet/questionnaire, you will not be disappointed https://www.guerragroup.com/camshaft-help

Yes I would definitely do a a new manifold, you could do a MSD, however a better choice might be going with a FAST and a ported TB to match it and a new DYNO Tune - The LS2 manifold is a huge choking point and very poor design, as a matter of fact even doing a LS6 manifold over the LS2 would be better

Thanks,Matt

 

Where is the proof for that? All the dynos I have ever seen show that there is a 30 to 35hp advantage over the ls2 in the ls3.

 

 

Yes, no, maybe.

With high lift cams, you will need to be replacing the valve springs around every 30K.
With radical lobs cams, then tend to trash the lifter rollers on the quicker side as well.

 

I have a Dyno printout I have attached below

 

Hence the link to PatG and not a off the shelf uneducated guess for someone for a random cam - too many people take a cam a motor and throw a huge cam in it and think all is okay and all is "NOT" okay and trash their parts and do not make the power they wish or thought that they would make -

You did see the reference to PatG and the link that I provided for the correct direction in selecting the proper parts for his current and future set-up?

Thanks,Matt

 

There is absolutely nothing wrong with the Vitesse and it's one of the best mods I have done to my car, allowing me to adjust the laggy throttle response exactly to my liking. The best mod was tuning out the torque management, tweaking shifting, and bumping timing in a few places with HPTuners.

 

Does it add HP?..NO it does not..The best way to go is with a ported throttle body which greatly improved my throttle response without any problems like with the Vitesse thing.Note: I do have a cam,LTs,intake and a custom tune...I did not want my tranny screwed with.