Guys I am still getting spikes with my boost, I have just a downpipe and catback exhaust and I am getting spikes!!!!! i was talking to my rotary mechanic telling him that I cant afford an ecu right now, and that instead i will invest in a boost controller to keep the boost down to 10 psi. I was thinking of going with the Greddy Profec B boost controller. He told me that boost controllers are garbage and there useless, he says i should port out the wastegate to control the boost. Does he have a point? I mean I cant afford an ecu right now, until maybe later down the road, and i have to eliminate these spikes i get, and the cheapest way i think and i could be wrong effective way of controlling boost would be going ahead and purchasing a boost controller, preferably a greddy profec b boost controller. So whats your guys is take on this?

 

Boost controllers are not worthless at all.. save yourself some money and try the home depot boost controller. I had some problems controlling primary turbo boost and transition boost, this fixed my problem 100% and cost me $10.

Matt

 

If you can afford a greddy B you are close to being able to get a used ECU I picked up mine M2 for $400. cheapest I have seen a greddy B is ~325. I am also using the Home Depot controller since the ECU is set to 13 psi.

 

boost controllers are one of the best things since sliced bread,but it is not going to control your spikethe best way i found to control it is by porting the wastegate and i do this to all the motors i build . the fuel cut on a stock ecu usually doesnt come on during the transitions of turbos which is where the "spike"usually occurs why dont you just change the pill to lower the boost for now

 

rx4ur7 makes a good point, but porting your wastegate will only help boost 'creep.' That is the boost slowly creeping up higher in the high rpms. A boost spike, like you see at transition in many cars, is not directly related to the size of the wastegate. If you install a home depot valve on the wastegate and the precontrol, then go out and tune them properly you will not see spikes.. or at least that was what happened in my case. HTH.

Matt

 

hey anybody have a site to show you how its done? the home depot boost controller?

 

This is where I found it. http://www.rx7turboturbo.com/robrobi...controller.htm

 

if you want you can give me a call and ill gladly guide you through it. and regardless when you install a downpipe and everything else is in good working condition you will have to find some way to lower the boost and there are a couple ways to do it but with only the mods you have the proper way would be to change the "pill". my name is chad 954-461-5453 if necessary i can help guide you through any of these procedure

 

Why would i want to boost lower then stock levels? I mean arent there guys on the forum that have downpipe and catback that are boosting 10 pounds with boost controlllers? If i change the pill then i am robbing horsepower by lowering the boost correct? i have been told that if the turbochargers arent operating at there 10 pounds its bad on the turbo chargers. Say i do change the pill cant i change the pill so it stays at 10 psi? why go lower, you lose horsepower

 

i wa under the impression that you were getting fuel cut and if so you need to lower the boost to ten or below (10 or below in the second turbo) so that you dont get fuel cut. if we are only talking about it spiking during the transition of the turbo(transition is about 5000 rpm)and then coming back down ,this isnt your solution(changing pill)the only way ive found to control this problem is porting the wastegate i have the home depot system on my car and noticed the spike actually got a little worse and it wont hurt the turbo running less boost

 

I got the homedepot manual boost controller (it cost me 6 bucks) and it has brought down my boost to a very nice and safe level. I would try the manual boost controller first because of the cheap price and the easy to install!

BTW: I agree with mjw, porting the wastegate won't take care of boost spikes, its for boost creep.

 

My stock boost levels are running near 12-13 psi in 5th gear...is this boost creep? Why is this bad?

 

to control your spikes u need to put a valve in your pre control line, then with a basic "home depot" boost controller you'll be able to tune it for the boost you want and get rid of the spike using the pre-control valve.

 

but why is my 12psi bad?

doesn't it give me more power?

 

with a stock ECU, 12psi is bad. since it was programed to run at 10psi nominal, it will not supply enough fuel at higher boost levels.
engine runs lean, apex seal goes poof, you just made a big A$$ paper weight. maybe not today, maybe not tomorrow, but sometime it will happen.

 

exactly, isn't fuel cut inthe 11 psi range anyway? someoen posted a chart a while ago that had the the differnt fuel cut PSIs at different RPMs

 

that would be an interesting chart. ive been working on these cars for years with a few very reputable shops and ive always known it to be 10psi in the second turbo but with the 1st turbo you can actually run over 12psi with no cut

 

1000 rpm 11.8 psi
2000 11.8
3000 12.4
4000 13.3
5000 11.3
6000 10.7
7000 10.7

 

thanks, you learn something everyday