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t3/t4 boost lag 4k


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No wonder it takes you soon long to get to 14 psi, your label states you are only using 13 psi! LOL. Just kidding.

 

What wastegate are you using?

 

What have you done to the exhaust side of the turbo (turbine wheel stage, a/r housing, clipping, ect)

 

What trim are you using with your T04E?

 

How old is the turbo? Are the bearings in good shape?

 

4K is pretty bad, however I just recently switched from a straight T3 which gave full boost (12 psi) at 2800 rpm to a T04B-H3/T3 stage 3 which now gives full boost at 3500 rpms. And 2-3 psi at 2500, 5-6 psi at 3,000 and 12 psi at 3,500. But, I'm getting another 1,000 rpms of usable engine power on the top end with the T4/T3.

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My 60-1 spooled 3500rpm or so (never really had time to pay attention. :D ) and that's bigger wheel than any E trim wheels so you should be spooling faster than that. Even with bigger T04E housing. Retarding timing into boost suppose to help spool if you got a standalone. Good boost controller will make difference too. I had TurboXS unit and that helped some I believe.

 

Lockjaw ran To4E 60 trim with stage V wheel and that spooled before 4000rpm I think. (where is he anyway)

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its a 57 trim, .63 a/r housing and I have no idea what trim or stage turbine. the turbine housing was orginally a .48 so I switched it out with my factory .63. would this effect boost? I'll try retarding timming a little an see if that helps. right now my timing set at 24

 

 

 

 

 

 

tbs

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Hmmmmm........

 

Yes swicthing to the 0.63 exhaust turbine housing will slow boost a little but not that much. Maybe 200 or 300 rpm difference. The .48 will spool up quicker but will not flow enough for the t4 compressor.

 

Who built your turbo? Is there a chance they clipped the exhaust turbine wheels to improve flow? Radical clipping of the exhaust turbine wheel will really slow down spooling.

 

I'm not 100% sure but the 57 trim on the intake compressor could be the problem. I remember reading that a 57 is too big for a L28. I'm sure a turbo "expert" could offer more information. Maybe you should post another question aimed at compressor trim sizing and boost responce. I'm surprised you didn't get more replies to this post.

 

Try manually locking your wastegate closed and see if boost comes on sooner. But be carefull not to over boost. Could be a wastegate problem?

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tbs

 

When you say 14psi @ 4K RPM, what gear are you in? What's your gearing?

 

I am running a T3/T04E w/ 57 trim compressor. I am not running 14psi yet, but I would say 3.5K-4K RPM is right around where I get full boost in first gear@ WOT. Usually, I am going too fast to have time to notice exactly when I get full boost.

 

During normal driving and easy acceleration, sometimes I'll get no boost at all in low gears. In higher gears, the boost comes on sooner.

 

I think it's a normal compromise of having a bigger compressor.

 

If you're using a bleeder-type MBC, that could be causing some turbo lag as well.

 

Sean

73 240Z, L28ET, T3/T04E, NPR IC, Z31 ECCS

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Are you runnning the factory catalytic by any chance? if so that is likely the reason, my boost went up when I switched to a high flow unit (without touching anything else). Also as you suggested, 14 psi and 2.8liter is a little much for the starion intercooler, so that is likely part of it. You can easilly have a 5psi loss thru a restrictive ICU, so your turbo may be building close to 20 psi for you to get 14 at the manifold.

Definitely play with the timing as already suggested, I find these cars so sensitive to small timming changes once the boost is turned up over 10-12psi.

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Im actually hoping my t62 doesnt spool up until 3500 or so, Im willing to really sacrifice the low end for big top end. Im going to be running a .58 exh housing so spool shouldnt be that bad. People tell me Im gonna lose races, I think Im gonna WIN... :twisted:

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