weird boost? laggy

[FaberNZ.blaaack-S15]

So my cars on 10 pound max but it only gets there at max rpm like 6500rpm, i thought full boost should be on at like 3500 and also my car is very slow and unresponsive at down low rpm but only gets going at high rpm. is this normal or is there something not right?

 

[spoonman]

has this only started doing this or has it always been like it

 

[FaberNZ.blaaack-S15]

always been like this the boost takes so long to come on. has it been purposely tuned like this? like i know my brothers evo gets at full 14psi straight away

 

[Auss15]

What turbo is it ?

 

[FaberNZ.blaaack-S15]

not sure of brand T28

 

[fez06]

Mine does this buddy people keep saying its a leak. Iv just put a boost controller on an all I can hit is .57 bar untill over 6k

 

[S15_SAM]

That's not right. Even with stock boost solenoid it will be .4/5 bar until about 3.5k rpm then it should be .7bar, then at 6k rpm it will tail off alittle

 

[JaseYpk]

As said, boost leak would be your top bet. I had a cracked intercooler pipe on the standard WMIC that took FOREVER to find, and was stopping me boosting about 0.5 bar, and causing over fuelling, rough idle, backfires.. etc.

Check ALL your air lines. From the big metal ones, check the flanges are in one piece and all the bolts all in place, and check all silicone/rubber lines to make sre they aren't worn/loose. There is no need to overtighten everything as you'll only break something. 1 bar isnt a lot of pressure at all in general terms, so an air seal should be easy to make.

 

[dave_t]

i had a similar problem when i first imported my S15. turned out to be a defective knock sensor (wires had split)

http://forum.s15oc.com/showthread.php?10269-Hesitation-When-on-Boost&p=112354#post112354

 

[spoonman]

Faber:
Looking at a photo of your engine bay, you could change a few things. Your intercooler & hotpipe is way too large for T28 running low boost levels, but dont change the intercooler, if you look at the size intercooler a EVO runs at a million psi you will understand what i mean by too large.
Buy some of that custom intercooler piping off trademe thats 50mm the cold pipe could be reduced to 63mm but at 70mm it will be OK, but definatly reduce the hot pipe size to 50mm. 63 and 70 hot pipes are for GTRs and 2Jz T304 powered things running 30psi and feeding a massive intercooler.
Also change your actuator arm length, if you have a air compressor, then GENTLY pressure the thing and adjust shaft bolt until it stays closed until your boost level.
This alone will gaurantee you will be hitting full boost by 3500.

A GOOD EBC will do a slimilar thing, one where you can adjust things like gain and responce. But altering the hardware that does the job is the best way to make your turbo respond.

Look on trademe for the intercooler piping, its $20 a section, and comes in all kinds of angles, all bits 600mm long.

 

[CMR]

His intercooler piping looks fine to me.

The one thing I did notice though is that in the picture showing the adjustable actuator, the arm from the angle of the picture is not set right, as the waste gate lever is at a 180 degree angle, it should be more like 200. This means the wastegate flap isn't being held shut, causing late spool.

 

[FaberNZ.blaaack-S15]

sweet thanks guys i'll have a play around see what happens

 

[FaberNZ.blaaack-S15]

wow im in a bit of a pickle haha took the actuator off and it when flinging back with heaps of tension now its too hard to get back on it has so much tension i cant move it with my hands. it looked real easy in videos i watched..

 

[Auss15]

Have you loosened the bolts on the bracket to give you some slack? It's a bit of a fiddly job doing it with the turbo fitted.

 

[spoonman]

you will need to get your man hand out and a pair of pliers, and as my XXXX drinking mate above mentioned loosen the actuator bolts, didn't loose the circlip did you?

I just took a photo of mine for ya see the precisely calculated angle there, thats straight up 14.5 psi angle

 

[Auss15]

Nice and clean Spoonman and no leaks. Those Greddy/Trust braided lines ?

 

[FaberNZ.blaaack-S15]

so what am i looking to do extend the rod or tighten it in more so im pulling the wastegate out more. i've got it back on now but its not adjusted i had to hook up the hose to the wastegate to my air compressor haha. and yes i did lose the clip.. i didn't even realise it came off searched everywhere for it.

 

[FaberNZ.blaaack-S15]

it seems to be weird i thought it should be able to reach it fully wound out but it was no where near and even winding it in and using the compressor it still doesn't reach the hook on bit

 

[Auss15]

You have to wind it in the increase the waste gate pressure, and to do that it has to be free from the turbo circliped end.

 

[FaberNZ.blaaack-S15]

yea tried that wound it in a bit and was no way i could get it back on i think its as far as it can go pulling out of the wastegate hard to explain but i think turbo and stuffs different because the hook on bit where the circlip is can only go back as far as 90 degrees its weird ill take a photo of it