Rayman93RX7

iTrader: (4)

I have a Home depo boost controler hooked up, but I can't stop these spikes. The constant boost does drop to 5-7 if I leave it open and I can dial it in to 10psi but that also makes the boost spike worse(only the primary spikes, I get no boost spike with the secondary). Should I run bigger lines to the boost controler? will that help

What causes this spike anyway and what is the best, cheepest way to fix it.

Thanks

r0t0r-rooter

Try using 2 manual boost controllers if you haven't already.

Rayman93RX7

iTrader: (4)

two in the same line? or one for pre spool and one for boost

r0t0r-rooter

I'm sorry, i should have specified 1 for each turbo (1st turbo & 2nd turbo prespool). I know Batmobile has 1 for each in his, limits it to 10 psi, and it will still spike occasionally. I don't believe there's a way to totally eliminate it unless you go non-seq.

Rayman93RX7

iTrader: (4)

so spikes are normal? will it ruin my motor? what about a eletronic boost controler?

air flow MODS:

cat back N1
dual custum intake

P'cola FD

Run a needle valve in the prespool line, and one in the wastegate line. I never encountered spikes with that setup, but I also have a ported wastegate. Just make sure to tune them both properly. If you have an automatic, then spikes are going to be a problem. If you have a manual, you can minimize them. Too big a spike can kill an engine.

Rayman93RX7

iTrader: (4)

I know porting the Wastegate will stop boost creep, but I didn't know it stopped boost spike, does it?

cuz no matter how I tune the manual boost controlers I still get a spike, however I used an air pressure regulator instead of a H-Depo valve for the boost, that stopped the spikes from growing when I turn up the boost.

P'cola FD

The problem is the solenoids not opening quick enough. The answer, as you've found, is something that is designed to control boost without the solenoids.

Snook

iTrader: (12)

i have intake, full exhaust with midpipe and streetported motor and I just installed one bleed valve from the wastegate and I'm getting 12 psi till redline and maybe 13 at night when the temp drops 15 degrees. I don't see why you are having so many problems

P'cola FD

Some cars just behave differently. Like boost creep (on cars without ported wastegates) is partially dependent on ignition timing. The more retarded your timing the more boost creep you'll have, because the fuel is burning later in the power stroke.

Snook

iTrader: (12)

i dont have a ported wastegate either
maybe its the pettit ecu that I have that is bumping up timing

Rayman93RX7

iTrader: (4)

I think I've found my problem tell me what you think. The high flow intake I have on the car lets more air flow to the #1(primary) turbo which alows it to spool quicker than the stock ECU thinks it is. And since the stock ECU blindly opens and closes the wasegate without monitoring presure I am building up pressure too quickly plus the wastegate is closed while pressure is building in the system. This (I realized today while tuning) 14psi spike only realy happens below 3,000 rpm after that (I beleave the Ecu opens the wastegate) the pressure then drops to the bleed off valve set boost of 9psi. So this tells me that the stock ECU sucks and somthing must be changed with it/get a programable one in order the fix the spikes. Mainly the waste gate must be manifold pressure activated/controled.

r0t0r-rooter

I dunno..... when I had my hi-flow cat put on, it would spike to 15 psi (to go with intake, dp, cb). I bought and tried the "dawes device" i.e. home depot boost controller. Did nothing. Bought and tried the blitz daul-solenoid-electronic b.c. It would then build boost until i eased off the gas (i've seen it hit 17 psi). Only when I put the blitz on the primary and dawes on the 2ndary (because I know how to adjust the dawes) would my boost finally come under control. Now I have 11 psi max which comes on a *little* bit slower than before with occasional spikes to 13. My car seems to react differently then others', so sorry i wasn't much help

Rayman93RX7

iTrader: (4)

Here is the big dicovery I've made. The car is meant to have the stock restrictive air flow system. Without it everything about the way the twinturbo oporates is thrown off. All the actuator, wastgates ect.. are preset to function at certan rpm/fuel mixtures. I guss mazda assumed that no one would ever touch/inprove the horable, unreliable design of the car an be happy with a slow 40,000 car (thats what it was new!) when they could buy a Viper and go twice as fast. Anyway unless you have the stock ECU reprogamed you will always get spikes, creeps - annoying things that can lead to big engine cost. It's just so frustraing cuz you can feel the cars potental, you know you could be running like 350hp but the freekin ECU has no ideal what the hell is going on so you can't. So lets all go out and buy an AEM or Haltech oh wait they are $1,300 !!