Having a problem with boost creep (up to 18psi!) on stock Sy

[Turbo Heaven]

Hello,

A friend at work is having problems w/ his Syclone (BTW, it's nice, like 24k and 99% stock ). Anyway, he put a straight through muffler and a few other exhaust things on it and now he seems to be having problems with boost creep.

Stock the truck makes about 12-13psi, but with the exhaust it wants to keep shooting up to about 18 or so PSI and of course, that and cast pistons don't live well together. He just runs race gas in it so it didn't blow his engine, but he said it was close to detonation. They installed a chip in it to try to help it.

At first he said the boost was coming on too fast and the stock MAP sensor and solenoid weren't fast enough to control it, he said the chip did help.

I was trying to help him figure out how to run an external wastegate, however, the engine compartment in those little trucks are very tight. So, what choices do we have? I thought maybe the swing gate hole on the turbine housing is too small, therefore causing the problems. He said with GNs you can just get a different "puck" for it but wasn't sure about the Syclones.

So what do you think? Thanks for any advice you have!

In the last pic you can see where him and a friend elongated the rod for the wastegate trying to see if that would help.

 

[dgoodhue]

Elongated wastegate rod? The factory one is thread and can be opened up enough so the truck will only make 5-7psi and spool very very slowly.

Anyone I am assuming he gutted the cat, which is casuing the over boost. If he still has a cat, I woul dcheck the wastegate operation, it could be a vacuum line, solenoid, actuator or a sticking wastegate puck.

 

[Turbo Heaven]

Well, he bypassed the stock setup completry trying to help the problem, so now the turbo is referenced right off the of the WG instead of going through the stock setup. I'm not familiar with Syclones, so I don't know the proper terminology.

 

[Ian Turgeon]

your going about this all wrong, you dont need to run race gas at stock boost levels (14.7psi btw), if you do theres something wrong that should be fixed (not with race gas). Theres no point to running it.

The problem is the stock wastegate is very ineffective, and opening up the exhaust any is going to amplify it. Some get away without any problems, but it is very common.

At any rate the problem started ( or atleast got worse) by modifying the exhaust. changing the chip, lengthening the rod and removing control of the wastegate arent the right answers to the problem. You can adjust it all you want, that hole isnt going to be any more effective.

lengthening the wastegate rod by adding material is just nutty? Was the threaded portion not long enough?

Put a cat/muffler on it or modify the wastegate so it can handle it.

 

[Turbo Heaven]

It's not my truck and I've done nothing to it, this is the first time I've tried helping him.

I mentioned it was probably the swing gate/puck setup and hole in the turbine housing is too small, therefore causing the creep.

Are there any modified turbine housings that have a larger internal wastegate setup?

The reason he runs race gas in it is because he doesn't drive it, it just sits there, he just sometimes drives it just to drive it a little. He wants to keep it as stock as possible, but just wants this little mod. which is getting bigger as all mods seem to do :rotf:

 

[smeagol]

you'll pull your hair out trying to mod/fix the stock wastegate.

IMO, be done with it and get an external wastegate on the crossover...there is room for it down there. check out www.raceprovenmotors.com , there should be pics on there to give you an idea.