sluggish boost on transbrake
08-02-2010, 09:14 PM
#1
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sluggish boost on transbrake I am having issues tuning my setup on the starting line. Its a 5.3 w/ 6.0 heads, ls6 cam & intake, front mount 66mm t4 turbo .96a/r, bs3, exile controller, th400w/brake & a 3600 stall converter. I'm having trouble getting the car to spool on the brake, 2step set at 4000. Revs really slow to 3000 and then transitions to boost and takes off.... The problem is that it takes about 5-10 sec. to get to the transition. By this time the tree is dropping and I'm not spooled. I'm running 35 deg. on the brake. This little turbo should be screaming as soon as I hit wot imo. Any ideas? Thanks, Ryan
08-02-2010, 09:51 PM
#3
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ok i see where you are going. I can make boost at 2500 in third gear. That being said, and knowing its not a 3600 stall in my case, should I lower the 2 step down to something like 2500-3000 and live with what I can get for boost there? The car leaves really hard at 4000 on 10psi, but it takes a long time to get it there. Thanks again
08-02-2010, 09:52 PM
#4
How much timing are you running before you get to the 2 step?
Also, if you are running a 3600 stall, you shouldn't have the 2 step at 4K. 2 Step should be set at or below the actual stall. Have you tried dropping the 2 step to the stall? Just you dont have to be in boost before you get on the 2 step. It will build the boost for you once it starts popping.
Also, if you are running a 3600 stall, you shouldn't have the 2 step at 4K. 2 Step should be set at or below the actual stall. Have you tried dropping the 2 step to the stall? Just you dont have to be in boost before you get on the 2 step. It will build the boost for you once it starts popping.
08-02-2010, 10:01 PM
#5
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I am running 35 deg locked in as soon as i activate the brake. I have tried to lower it, but it just doesn't seem to want to build more than 5 psi at 3000 on the 2 step. Leaving at 4000 was a 1.44 60ft, 3000 was a 1.55 60ft. I can tune once I get off the line. This starting line setting seems to be a little more sensitive than wot tuning. LOL Thanks for the help.
08-02-2010, 10:42 PM
#7
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yes the boost will go to 15psi by 5000 if i leave at 3000rpm. Is that normal for a turbo car? Leave on lower boost and ramp in? I was trying to leave as hard as possible.
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08-02-2010, 10:50 PM
#8
Let's take a step back though. What engine management are you using? What does 35* locked in mean? You got a distributor on there or something? Surely you aren't hitting it with 35* at full boost, right?
08-03-2010, 06:13 PM
#9
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I am running big stuff 3 and I still have coils. I can set starting line timing in its own map. I have 35 entered the entire way up to the 2 step. After I release the transbrake button it goes back to the regular map. Its never higher than 15 deg under boost. As far as hooking up that isnt a problem.... its a 25.2 back half car. Thats why I was launching so high before. Thanks, Ryan
08-03-2010, 06:20 PM
#10
Things to try...
Advance the cam 4 degrees
wrap the pipes
add a turbo blanket
try timing up to 40 on the starting line timing map
fuel should be in the 12.5-12.7:1, do a static pull and raise the limiter to above your 2 step so you get a clean pull through the revs to dial in the fuel.
make sure you have no leaks
Send a BS3 log file to phillip_eclipse@hotmail.com
Advance the cam 4 degrees
wrap the pipes
add a turbo blanket
try timing up to 40 on the starting line timing map
fuel should be in the 12.5-12.7:1, do a static pull and raise the limiter to above your 2 step so you get a clean pull through the revs to dial in the fuel.
make sure you have no leaks
Send a BS3 log file to phillip_eclipse@hotmail.com
08-03-2010, 06:48 PM
#12
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I agree the converter is deff. too tight. I was told it would flash 3500-4000 with my combo. Its a consistant 3000 everytime. I figured it was too lean/rich or maybe timing needed tweeking to make more power off boost. I guess I'm stuck with 3000. I'm going to pinks all out at norwalk at the end of the month, so I need to get this thing as good as I can in the next few weeks. I've been trying for a few months and havent really made progress. I figured I would post and see what some people with cars like mine had to say. Thanks again guys, I'm new to turbo stuff. The last thing I had was a 38 chevy Streetroadster with a 540 and a glide.....Far from a turbo car. LOL
