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SB2.2 + pt106
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Ever since i have switched from my gt47-88 turbo (.96 ar) to my pt106(1.0 ar) i have had a world of issues with spooling.
The gt47 spooled SO fast i was expecting a little bit slower with the pt106.
I am currently around 8+seconds to see around 5# on the transbrake.
The car has a BS3 and a 7531.
I have a 2 step on the transbrake set at 4400rpm and that doesn't seem to help either.
So i am thinking of switching to a smaller 91-98 turbo to help spool up time. (rather not do, but would if had to)
I have read a bunch of threads about make changes on the transbrake area of the tune to help with spooling, but how much of a change will that be??



Little background.

Precision pt106 turbo

Engine:
408ci Small block chevy
Dart iron eagle block, Kryptonite billet crank,
Oliver billet rods, CP custom pistons,
Pro Action aluminum heads, Jesel rocker arms,
Solid roller duttweiler cam, Edelbrock super victor intake,
Jesel belt drive, Bigstuff3 EFI System


Drivetrain:
ATI SuperGlide 2 1.80 gearset
PTC 9.5" converter
Strange chromoly driveshaft
Fab9 rearend with Moser axles & ARP 1/2" studs and 3.40 gears
Liquid Transmission cooler from DeedsPerformance.com


Ignition:
MSD Digital 7-plus 7531 box
MSD Pro power HVC 8251 coil
MSD billet distributor
MSD crank trigger


Exhaust:
Custom made stainless turbo headers 1.75" primaries
2.50" crossover tube with dual HKS gtII 60mm wastegates
5" aluminum downpipe no muffler
 

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Yes tuning the spool up area will help. You should work on that before giving up.
Is it a Gtrim turbo? I dont think you will pick up much swapping to a smaller 98-94 mm turbo. They are all basically the same turbo.

My combo is similar to yours. 400 ci with a PT106 1.0 exhaust. 3.0 crossover single 60 JGS. About 4 sec to 6 psi (launch boost) No 2 step, 12.5 afr average during spool up, 31 deg timing. I have been playing with it after tightening the converter. Im gonna put a few more degs in and it should get better.


Here it is with the old converter. 4200 on the 2 step, 4-5 psi launch .The old converter was loose but it spooled fast. !

http://www.youtube.com/watch?v=MI_mElnQecE
 

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SB2.2 + pt106
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1,928 Posts
Discussion Starter #5
Yes tuning the spool up area will help. You should work on that before giving up.
Is it a Gtrim turbo? I dont think you will pick up much swapping to a smaller 98-94 mm turbo. They are all basically the same turbo.

My combo is similar to yours. 400 ci with a PT106 1.0 exhaust. 3.0 crossover single 60 JGS. About 4 sec to 6 psi (launch boost) No 2 step, 12.5 afr average during spool up, 31 deg timing. I have been playing with it after tightening the converter. Im gonna put a few more degs in and it should get better.


Here it is with the old converter. 4200 on the 2 step, 4-5 psi launch .The old converter was loose but it spooled fast. !

http://www.youtube.com/watch?v=MI_mElnQecE
Yes this is a G trim. So you think adding 4* everywhere in that map would make a big difference?
 

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I cant give you an exact amount of timing to throw at it. But I do know that tuning that area to the max helps alot. I know some are running 36-38 deg of timing in that area. You may need to get aggressive with it to get it over the hump, then start pulling timing back...fast. One thing I ve learned is that although some of those blocks show 34 deg of timing , the surrounding blocks have a great effect on how much total spark is being applied. Datalogging the spool up and seeing the spark during that time will show the true timing the motor is seeing.
 

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4 degrees can help. The other very important issue is your afr during this time. If it's low 12's or high 11's it can also slow down spool time.

Putting a 3 step on it at 3600-3800 so that you can get on the 3 step in the pre-stage beams can also cut the spool time down once you bump into full stage.

Your converter should work well with that size motor and the 106mm.

Have you verified the timing on the balancer matches the timing in the BS3? You can be commanding 36* but the engine might only have 30* if the crank trigger isn't dead nuts on.
 

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I sent you an IM.
 

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Cam timing helps some as well, advancing the intake centerline to 108-110. And on a controversial subject, a more N/A type camshaft may work better since you have less backpressure on the exhaust side now!

How is the downpipe off the turbine housing made? Is there a tight bend really close?
 

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air fuel ratio and timing are your friends when it comes to spooling. The 3-step in the stage beem will help tremendously as well!
 

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I'm having trouble spooling up mine also and 2 people in here told me the same thing.more timing,lean it out, 2 step it to pre-stage and again into the lights.i haven't tried it yet,but i have no reason to doubt them.
Thanks Tim,Jesse.
 

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SB2.2 + pt106
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Discussion Starter #15
Cam timing helps some as well, advancing the intake centerline to 108-110. And on a controversial subject, a more N/A type camshaft may work better since you have less backpressure on the exhaust side now!

How is the downpipe off the turbine housing made? Is there a tight bend really close?


the camshaft was groud/designed by kenny duttweiler. the LSA is 115 and it is installed on a 110

here is a pic of the downpipe routing.
 

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This is what i fownd whith my set up.I hav a 357 sbc that had a gt55 91 whit a 124 a/r on it. It wood leve at 9 psi at 4600 rpm. That whas with a 2.2 pound spring in the 60mm gate.Then i put a 106 on it whit a G trim and a 100 a/r . It wood not spool for shit.The exhust flow so much beter than the gt55 that i had to put the big green spring back in the gate.Then it wood spool rite up to 7 psi whit out a problem. That is my two cents.
 

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TURBOBULLET.COM BITCHES!
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Are you footbraking it up before you light the 2nd bulb??? I'll bet you are already doing this, but just in case:

You need a rev-limiter hooked to the brake light switch so you can get a little boost behind it before you hit the transbrake. Here's what I do... Light first bulb... Stab the footbrake, stab the throttle, watch the boost gauge... As soon as it gets about 1-2psi on the gauge, ease in and light the 2nd bulb... Hit the transbrake button, rev-limiter goes to the setting on the transbrake. At this point, the boost climbs really fast to whatever the AMS1000 has it set for launch psi.

At least that's how I do it... Again, my old setup was DAMN close to yours, and it spooled very easily with a Gtrim 1.0 A/R PT 106/101..
 

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SB2.2 + pt106
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Discussion Starter #18
Are you footbraking it up before you light the 2nd bulb??? I'll bet you are already doing this, but just in case:

You need a rev-limiter hooked to the brake light switch so you can get a little boost behind it before you hit the transbrake. Here's what I do... Light first bulb... Stab the footbrake, stab the throttle, watch the boost gauge... As soon as it gets about 1-2psi on the gauge, ease in and light the 2nd bulb... Hit the transbrake button, rev-limiter goes to the setting on the transbrake. At this point, the boost climbs really fast to whatever the AMS1000 has it set for launch psi.

At least that's how I do it... Again, my old setup was DAMN close to yours, and it spooled very easily with a Gtrim 1.0 A/R PT 106/101..
I am not actually, well not fully. Id roll in like at 2k rpm or 10% throttle or so.
I talked to tim today and he gave me some pointers for setting up the car for the 2 steps. Going to pull the car out thursday, do a datalog and also see how much rpm i can get on the footbrake before it creeps/spins.

My old turbo i could roll into the stage beams and floor the car on the brake and it would be at 5psi in less than 2 seconds. This pt106 is really a tough guy to get spooled.
 

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i have a 408 sbf with a g trim 101 (1.0 a/r) i have a 10'' ultimate converter in my car and have footbraked it to 3500 and 5psi in 3-4 sec and hit the t-brake and it shoots to my 4k launch limit and 10lbs pretty quick. i would do like some have said and hook the 3 step onto the brake pedal and itll help along with the tuning
 

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It is all in the converter and the tune up. I have a 400ci sbf with a g-trim 106. I spooled it up in the grage the other day with a 1:5 A/R housing on it. You are getting good info on here. It is all in the timing, a/f ratio, camshaft, converter, and compression ratio.

I spool (pre-stage beams) at 4,400 rpm. I launch somwhere above that.
 
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