who makes 3" turbo back exhausts?... Im looking at the ultimate racing one...seems good... anyone else make one? Id rather do that than just an axle or cat back.... also anyone have hp/tq gains? THANKS

-Shahul

 

bushur racing has a full 3 inch turbo back exhaust for under 800 bux. Give them a call, look on their site for pix. Also available through Machv.com

 

Use the search function

 

Also get your self a boost controller and boost guage while you are at it if you don't already have one. Upping the exhaust that big and with it being a turbo back.....you may have boost creep issues. Just an FYI. Better to be safe than sorry.

 

i have an HKS EVC V on the way...(paid for)... I saw the Baschur and wasnt that impressed...looks odd (cheap....being nice), the UR exhaust loks better...the THERMAL is cat back...guess I can get a 3" downpipe...

Can you explain turbo creep? Ive owned several cars...1st turbo

-Shahul

 

boost creep is where the exhaust cannot flow fast enough to release all the gases given off by the waste gate. A high flowing large exhaust will cause more of boost spikes in stead of creeps. Spikes happen becasue the wastegate cannot regulate the exhaust gasses fast enough to control the boost. The turbo will spool up faster then what is did from the factory and the stock components were calibrated to regulat gases at a stock spool level. I hope that was understandable lol..... Worry abotu boost creep when u go to purchase boost controllers and if you look to do turbo upgrades. on a stock turbo worry about boost spikes

 

Since you are putting on a larger exhaust of course you are going to get more flow. Sometimes too much and your wastegate cant get rid of the boost fast enough. So if you have your gauge you will be safe cuz you can catch it. It is normal to see a spike and then settle back down to your set psi (stock). Lets say you are set at 15psi for example and you just installed your lovely new toy. Watch the boost gauge....floor it it will most likely spike to say 16 and the needle will go back down to 15 and stay there. If you floor it and the needle jumps to 16 then 15 then slowly builds 16,17,18, 19 that my friend is boost creep and is not good. Worst case scenario is you will blow your engine. if this is happening the best way to get rid of it is porting. Remember also boost creep gets worse the higher the RPMs. A MBC might help you out in this area. Feel free to correct me on this anyone.

 

Adding a free flowing exhaust as his can DEFINATELY cause boost creep. It is very common (for eclipses) adding a 3 inch exhaust with a b16g can cause boost creep (not all will experience this but it is common). You are right however about boost controllers. Manuals are know to contribute to boost creep at times. Spiking is when the actuator can is taking too long to fill up and you go beyond your set boost level for a small moment but usually comes right back down. Your info is backwards. Boost creep is because the wastegate cant get rid of the exhaust fast enough basically you are pushing the 'gate past it's limits (usaully caused by free-er flow as in adding an exhaust). I am not sure if this may be the case with an EVO.

 

Dave Buschur was ask this question relative to boost creep:

There is absolutely NO boost creep issues with the EVO8. The boost is so steady it is almost scary.
The car has a very efficient wastegate and has held boost both up and down perfectly.
Our car is currently running our 3" full system with no cat in it, no creep at all. We have even regulated boost down to 12 psi with no problems.
David Buschur


Speedlimit......

 

Very good info to post there speedlimit, as I mentioned I was not sure if this was an issue with the EVO. It is a somewhat common issue on the 2g's when going with an exhaust that big. In a 2g, with the big 16g a 3inch is said to be a little over kill and caused a lot of creep issues. Thanks for clearing this up for us.

edit sorry forgot to mention the 1g's there too!

 

I had the same question about the EVO and spotted Dave's answer. MY 1G Talon had boost creep with just a 2.5" downpipe and exhaust from Buschur, so it was a valid concern for the 4G63.

Speedlimit........

 

To correct some... larger piping does not cause boost creep, it is the fact that exhaust gasses cannot escape fast enough there for building unwanted boost. If it was an issue with larger and higher flowing piping the whole "dump tube mod" for o2 housings would not make sense becasue basicly all that is doing is making the wastegaste as free flowing as possible. The reason PSI levels increase when putting on a free flowing exhaust is becasue the turbo can "spool up" faster and is building boost quicker then before. The exhaust will flow more air over the turbine and in turn building higher boost. I wouldn't exactly call that boost creep, i'd call it physics...

Boost creep is when the throttle is held down and the car is at the preset boost and as RPM's climb boost is still being built, while in a gear; not between gears as happens when shifting those are spikes....

The whole 2g eclipse boost creep issue was becasue the o2 housings couldn't flow enough air flow through them, and the wastegates air flow would outflow the limits of the o2 housing. Once again another reason the wastegate mod came into an effect.

just my two cents.....

 

just so you all are aware, a full turbo back exhaust voids you factory warranty. a cat back doesnt !!

 

I'm gonna agree here. I think we are both saying the same thing in so many words or less.

 

I can confirm the lack of boost creep with the Buschur 3" exhaust, as mine reaches the 20 psi point, and never goes over it, even under hard acceleration in 3rd/4th gear.