bad overboost problem

[kjizzle]

alright... lately i've been going to make a run, say from a stoplight or an empty road or something, and if i don't roll into the boost it will skyrocket to usually 35-40 psi, stumble and pop, then i let off.


i've got razors kit, so this is probably whats saving me here. i went ahead and replaced my turbo (not because of this... i got a good deal and my stocker had brushing fan blades and blowing oil). got a new wastegate actuator with this (thanks 49-blues!), put it all together, and it still does it. if i roll into the boost, it will hold rock solid at 22 PSI right where i want it by WOT, but if i punch it it will spike to 40. what gives?

i do have an exhaust leak by the bolt nearest the wastegate thats always been there (bad gaskets????) on both turbos. the leak was bad enough to burn through the old gasket, didn't have one on hand when i installed the new turbo so i made one. still has a small leak. could that be it maybe?

 

[87NAT]

This problem happened after you chanaged the WG actuator also? Unscrew the rod all the way so that a;; the threads are showing then take it for a spin. The boost should blow open that puck almost immediatly therby giving you a low reading.

An exhaust leak will lower...not raise boost. You are losing pressure at that point.

30+ psi of boost is burnt piston/headgasket changing territory. Address this high boost problem before going WOT again before you do any major damage.

 

[Royal-T-Ltd]

you might need to port the wastegate hole to alleviate some boost - you might be making more boost then you can get rid of via the wastegate hole - this causes the exhaust wheel to spin faster, which creates MORE boost and leads to overboosting and A LOT OF HEADACHES if you arent careful... and YES I AGREE - Razors ALKY is probably the only reason you are still driving.

 

[87NAT]

you might need to port the wastegate hole to alleviate some boost - you might be making more boost then you can get rid of via the wastegate hole - this causes the exhaust wheel to spin faster, which creates MORE boost and leads to overboosting and A LOT OF HEADACHES if you arent careful... and YES I AGREE - Razors ALKY is probably the only reason you are still driving.

I know for a fact Razors kit kept my motor together on more than one occasion.

 

[49-blues]

If you re overboosting- theres a restriction somewhere, wastegate hole needs to be enlarged but i dont think so or possibly a clogged catalitic converter causing backpressure?

 

[kjizzle]

no cat, so thats not it. i've just been taking it easy on it lately trying not to go above 20, but if i ease into it theres no probloms rock solid 22. ill try unscrewing the actuator rod some more and ill tell you guys how it works.

no new problems have come of this. i did a compression test and all 6 cylinders are within 10% of each other, so no headgasket problems. no burning coolant no NEW burning oil (old valve seals). my factory headgaskets seem to be tankproof...

 

[knucklehead]

try unpluging the boost noid!!!!

 

[kjizzle]

its not in the circuit anymore.

compressor ==> boost controller ==> wastegate actuator.

 

[turbows6]

If it's shooting to 40#'s boost and you know the actuator is working and adjusted properly. I'd try another boost controller. Porting the wastegate probably isn't your fix.

 

[kjizzle]

i just tried going from the compressor right to the actuator, but that didn't help, so it can't be the controller. i'll try some other stuff before i try to enlarge the wastegate hole.

 

[jacksride]

overboost

My car was doing the same thing and I chased the problem for six months before I finally figured it out it was the after market boost controller went back to stock and no more problems.

 

[kjizzle]

i've actually always had a problem with spiking, but never this bad. not so bad with the stock setup. i had a hallman pro controller before but had a spiking problem, went over to this greddy profec electronic controller and have never had a problem until recently.