[SSallday]

Hi all,

I had my car tuned this past summer at a reputable shop. My car has the following mods: Kooks 2” headers, catless connection pipes, AWE track edition catback, DSX flex fuel kit, Roto-Fab Big Gulp, and new plugs. My car made 560whp and 605tq with these mods on E50. I’m not going name this shop because they did do a good job with installing everything but I know these numbers are not even in the ball park of what my car should be making. My friend who has the same exact mods and was tuned at the same place was around 620whp. Only difference is his car doesn’t have the 1LE package and has the A10. These results came from a dyno jet. I spoke with a few people and was told to bleed the coolant system. Would the coolant system rob my car of 60whp? What else should I look at?

[arpad_m]

Yeah, it is possible to lose 50-60 hp if you have large air bubbles stuck in the supercharger coolant circuit (not the regular cooling system).

Search for threads on bleeding the LT4 supercharger system, you'll find several excellent tips, including the ultimate solution of installing a reservoir.

[Joshinator99]

Originally Posted by arpad_m

Yeah, it is possible to lose 50-60 hp if you have large air bubbles stuck in the supercharger coolant circuit (not the regular cooling system).

Search for threads on bleeding the LT4 supercharger system, you'll find several excellent tips, including the ultimate solution of installing a reservoir.

Yep, if the intercooler circuit is air bound it’ll pull timing like crazy.

[SOCAL.M6.ZLE]

Originally Posted by SSallday

Hi all,

I had my car tuned this past summer at a reputable shop. My car has the following mods: Kooks 2” headers, catless connection pipes, AWE track edition catback, DSX flex fuel kit, Roto-Fab Big Gulp, and new plugs. My car made 560whp and 605tq with these mods on E50. I’m not going name this shop because they did do a good job with installing everything but I know these numbers are not even in the ball park of what my car should be making. My friend who has the same exact mods and was tuned at the same place was around 620whp. Only difference is his car doesn’t have the 1LE package and has the A10. These results came from a dyno jet. I spoke with a few people and was told to bleed the coolant system. Would the coolant system rob my car of 60whp? What else should I look at?

Hey buddy, sorry for the poor results. I agree, the number seem way off. What did the car baseline? Do you have a datalog of the dyno run you can share?

[SSallday]

I don’t know if they did a baseline run but it would have been nice to compare. I have the dyno sheet but that’s about it

[Megahurtz]

Could just be a conservative tune by someone who doesn't know how to tune the LT4. But a tune file and a data log would be helpful.

[SSallday]

Originally Posted by Megahurtz

Could just be a conservative tune by someone who doesn't know how to tune the LT4. But a tune file and a data log would be helpful.

Unfortunately, I don’t know how to access that. My friend’s car made close to 620whp with the same mods at the same shop. Is there a reason why my tune would be more conservative than his?

[Megahurtz]

Originally Posted by SSallday

Unfortunately, I don’t know how to access that. My friend’s car made close to 620whp with the same mods at the same shop. Is there a reason why my tune would be more conservative than his?

Some times I tune cars that just don't like timing for random reasons. I've seen some shops just pull timing down to minimize knock and send it out the door. Different model year cars are more prone to closing the throttle if torque is out of line. I'm not saying that happened here but you never know. Could easily just be a dyno calibration error by the operator. Point is, without data, don't focus too much on the final number. Without a before and after, you're just guessing. You can make a dyno read higher or lower so you and your buddies cars could make the same TQ/HP but the dyno operator could have set the dyno up wrong for you and you got a low number.

If the coolant circuit wasn't bled well, then air pockets could cause knock retard which either causes the ECU to pull timing on its own and learn to keep it low, or the tuner could have backed down the timing without investigating why it wasn't taking timing. I've seen it happen where people run the wrong heat range plugs (too hot) and the LT4's won't take any timing if you do this with mods.

So by posting a tune and datalog some of us could take a look and see if something looks out of line. I would recommend you invest in your own copy of HPTuners software and MPVI3 interface.

[Marozl1LE]

how much timing and boost my dear ? can we see the log ? and how much degrees at the outside ? mesaured in the right gear ?

[18.2SS.1LE]

This was also done using STD, your numbers in SAE correction would likely be a bit lower. Something is definitely off.

[Ericdared]

Yeah you need to get a logger like the MPIv3. You would be able to see if it is pulling timing and why.