So i know that these are known for drivability issues but this is a new one for me at least. If i go full throttle or 5% throttle shes happy as can be, either putting along like a grandpa or shreding the tires and screaming forward. but if i go part throttle off the line or on the first to second shift she losses her mind and starts bucking wildly. i have to drop throttle completely, let her calm down and either 5% or 100%. happens very slightly at the start of third but its rare and minor. She wont work her way through it, she will buck until you let off the throttle, it takes a lot of getting used to. The problem with going full throttle in traffic is obvious, shes putting 300 to the wheels and will just launch if i go full throttle. makes city driving very irritating. always putting about or roaring forward.
does anyone know any tuning tricks or advice as to how to calm her down? ive read there is a way to alter the rate the TB opens to make it more drivable but i havent found out exactly how yet. im getting ready to start taking her to the track and im not trying to smoke tires on the first and second gearshift, something that seems guaranted if i have to bury the gas pedal all the time.
and just to cut off the trolls the answer is no, i will not go back to a stock TB. im willing to replace it with another ls4 if this is a problem with the TB itself, but i would rather live with it than go back to that enterprise rentacar throttlebody she came with. Forget that.

 

o well

 

It's a tune issue. I had the same condition before I dialed in my MAF scale and adjusted my timing...

 

Scaler set to 4950?

Even on a stock tune if the scaler is set to the number above car drives normally..

 

My scaler is at 6350, ...

 

not exactly sure what we ultimately set it at, might have been 4500. last tune was a couple of months ago, im hoping to get ahold of gremlin85 and hook up for some more tuning work. id love it if a little computer time was all it took to get her right.

 

Every car is different. But I had some fluctuations in AFR that caused crazy bucking and made the car very difficult to drive. If it's been working just fine since he tuned you, though, you may have something mechanical going on. How much do you drive the car? How long has it been driving just fine? When did the issue start?

 

adjust the base idle timing to 10deg that will help with any idle surh you may encounter on the tb scaler you can go as high as 6600 if your on the m62 i doubt your at 300

 

Troll here. The ls4 isn't worth dick as you stated and when you're done messing around with poor drive-ability for 3-4whp...Go back to stock. Just port it and you'll be close enough. The throttle response is crazy and gives you the feeling its a great upgrade, but wot gains are ****. If your tb is bad I have an LS4 I'd love to sell you for $50 shipped. Doubt the ls4 will make a difference in your et/trap.

 

$50!!! Zack payed $100 for mine

 

****! NM op! Its going up for sale on CSS.

 

glad to see your not in the know

 

4 Bolts & 5 minutes = 9 whp / 4 ft lbs (Significant gain for one of the simplest bolt ons)

It's as easy as setting the scaler to 4950 and simply zero'ing out your fuel trims using the maf, ve or both.

If that doesn't work, you have other problems.

 

Ok if hes on the mp90 then he gains 9whp. M62 half that. The m62 is not moving enough air to produce gains like that.

 

im going to do a bit of testing today at work and make sure the gas pedal assembly is working correctly, then see if i can do some testing on the TB itself. Im still trying to reach my tuner to get her looked at. The dyno doesnt lie. 10whp gain on my car with the ported ls4 tb. and of course the whole woke my car up aspect that id rather take a bullet for than give up.

 

Gl man hopefully you get it ironed out. You are determined.

What is your setup for making 300whp? e85? Pulley?

 

Subd for info

 

I thought about going for LS4 but I research about LS4 and decided this is not worth it. I am sticking with my stock TB and it is made for that Supercharger.

But I will port my Supercharger it will be good enough.

 

the tvs guys seem to love the ls4

 

Bigger gains have been had on the ls4 m62 combo.

The more air you cram in, the more air you need to get out
The mp90 at 24 psi makes this a difficult task for the exhaust side. The m62 at 15 psi is a different story

 

Anything that will help my car get more power, also I think a 2.5 on the tvs with ported head and Cams is flowing enough to outflow the stock tb

 

I'm pretty sure the OP has a TVS on not M62. I remember dyno threads he's done.

 

I bought his 2.6 euthanasia m62 so he should have moved up to a TVS

 

In for some good testing and answers

 

X2! I've thrown around the idea but don't know enough about the pros and cons of the swap.