Ok so there is ALOT ALOT ALOT of experience on here. Nobody knows what happened to my truck? I mean I know nobody can be for sure but hey, can i get a bone here, some ideas or something?? lol.

It pulled fine all the way to 120mph plus several times, but then when I brought it to the track it was a very noticeable loss of power at the top end.

And it progressively got worse as you can see by my time slips. 1st run and 2nd run mph was 4mph slower.

Also nobody has experienced the 600ft/lbs of torque limit?
I mean its not a big deal cuz i am biting the bullet and going for the Big Stuff 3 so that wont be an issue anymore, but I was just curious if anyone else had had that happen to them.

any guesses or input would be appreciated.

thanks

 

I noticed that your upgrading your fuel kit...is that because your IDC's are maxed out? Your tune might be pulling timing and fuel at top RPM's so you don't blow it up till your fuel system is ready. Is your boost consistent from the time you get full boost until you shift? What's your rear end gear?

 

I believe there are some parameters in the tune that start pulling timing at a certain delivered engine TQ... I have read alot of the vettes suffered from this on EFI Live forum, IMO you just need to tune it properly... Who is doing your tuning and what software do they use?

 

My AWD final gear ratio is 3.73 factory.

The duty cycle is at 92%

The boost is not consistent it starts to drop off after it pings at a little over 16.6 lbs. I have an Eboost controller so that isnt the issue.

Ed Wright from Fastchips tuned it, using GM Tech 2


I dont know what it is, but after all this and my truck is not producing the numbers compared to some of these guys on here that just slap a turbo on and a cam and go 12's.

I dont know, seems like there is a crucial "go fast" piece missing.

 

Were you going lean on the top end at all? Did you upgrade your fuel pump?

 

It has an Aeromotive pump on it that kicks in at 3psi

The thing is, it didnt do that on the street, I had it a few days and then I took it to the track.

It made some very good pulls ALL the way to 120mph plus on the street. But when I took it to the track it started acting up.

I dont think it is the tune, or it being lean. Ed Wright is supposedly the master mind behind GM programming. And he had the truck for quite some time tuning it.

Anyone have any tranny related info? Like TQ Conv or third gear goin out?

Possible??

HERE IS EVERYTHING I HAVE IN THE TRUCK:


Transmission:

Street/Strip 4L80E Transmission

Transmission core charge

Precision Industries 9.5 inch, 3-disc 3200

4L80E 4-bolt aluminum inspection cover

4L80E shift cable bracket

4L80E Transmission dipstick tube

Bolt - 4L80E inspection cover

4L60E to 4L80E wiring harness adapter kit

NP3/NP149 transfer case input gear for 4L80E

Custom Built Cross member

Custom Front Driveshaft and rebalance

Custom Rear Driveshaft and rebalance

Custom Transmission Cooler Lines

Custom TQ Converter Spacer

Custom Flywheel Spacer

Freight/Shipping for transmission related parts

Motor:

ARP Main Studs

ARP Head Bolts

ARP Rod Bolts

Timing Chain Set

Meling High Volume Oil Pump

Eagle Forged 4” Stoker Crank Shaft

Diamond Pistons 4.030” 28cc Dish Race

Diamond Ring Pack

Manley Rods

Clevite Bearings (Rods and Crank)

New Cam Bearings

Balancing and Machine Work

New Balancer Bolt

GM MLS Head Gaskets

All seals replaced with new OEM GM Gaskets

Full Motor Hand Assembly

Crank pinning kit

Comp Cams .588 .598 228/234 @115

Patriot Extreme Valve Springs, Retainers, ect.

Comp Cams Hardened Pushrods

New Belts for AC and Serp

LS2 heads

Fuel System:

Factory Pump (for normal driving)

Aeromotive Pump (for when in boost)

Aeromotive Filter

#8 AN Lines and Fittings

60lb Injectors

Turbo System:

Livernois Base Kit

Air to Air Intercooler

Precision T76-GTSH Turbo

Turbo Smart eBOOST 2 Boost Controller

3” Down pipe split to twin 2.5”

MagnaFlow Dual in and out Muffler

Tial Wastegate

Moroso Catch Can for PCV system

Now do you see why i am so frustrated that it only ran 13's? I mean yeah it weighs alot and it has big wheels on it, but still.....

 

I don't see how 60lb/hr injectors can feed +16 psi on a built 408. 60s should only be good to 650hp (safely). Sometimes high impedance injectors have a hard time accurately metering fuel at high duty cycle numbers. Hard to tell what's going on without a wideband, fuel pressure gauge and datalogging. If you have those things it would be easier to figure it out.

 

Yeah I was kinda worried when they said it was at 92% but now I am going with 83lb inj.

I dont have the info on the tune. Wish I did.

Do you think 83's are enough?

 

It depends on what your end goals are. It seems like others with similar setups to yours are running up to 96lb injectors. If your afr is okay with 60lb injectors, going to 83s should lower your duty cycle to about 70% or so which would mean you only have 10-20% more fuel that you could add if you turn it up and have to add more fuel. Just to be on the same page, are you running your fuel pressure at 3 or 4 bar?

I wouldn't be too frustrated for it being the first time at the track with the truck, just have to work out the bugs.

 

One guess on the lack of power would be a little detonation (or false knock) at the track caused your timing to suffer. It is hard to say for sure what the cause would be without looking at a scan.

I don't believe the 640ft lb torque limit will cause you any issues. I have some friends making 800+ft lbs to the wheels with stock PCMs. I would hold off on the BS3 until you get some bugs worked out.