bOOST SPIKE?????
 

I bought a 93 fd from a guy, he said it boost spiked when the second turbo came on line, looks like their are no cat's under the car. Guess what there is no fuel system either.
I just purchased another motor for it and i have two Questions. Should i find a set of cats to put under this car to avoid it spiking again or is there an inexpensive fuel controller i can get?
Second question is the motor i have is from a manual and mine is an auto. Should i atempt to change the rear housing from the blown motor to the good one. Im some what mechanically inclined, but i have never even changed the oil in a rotary motor. Is ther some sort of book i can get to help me with this project or do one of you guys have something that would be helpfull to me.

I was told that if i put it back togethger with the stuff i have right now i will be replacing the motor again real soon

Help me please i need some GOOD advice

please search...... you will find a lot of useful info.


also, to get you started, you need a boost controler to control boost not a fuel controller.

I understand what controlls the boost, however i was under the impression that the wastegate actuator on the second turbo could not be controlled when there is no back pressure present. Is this true ? What if i used a good boost controller the elcetronic kind ?

you can use restricter plates ( some use homemade pills)to control that spike........but its only a temp measure........from what i have read........a boost controller is used to increase boost........it does little to nothing to decrease boost........please search there are plenty of pages on such similar issues.......as far as i know the engine blocks are the same for auto and manual.......so basically its the same motor........

try www.iluvmyrx7.com you can DL the 93 shop manual for free from there.

There can be two different problems:

1. Boost Spike
2. Boost Creep

Spikes can be handled with good boost controllers, creep cannot.

Without the car running, you really won't know which one of the two you have. Basically, a spike is just as it sounds, the boost shots up but then settles back down. Creep means that the boost doesn't shoot up as fast as a spike, but it doesn't settle down as the wastegate can't control the flow.

Regardless of which one the previous owner might have had, without an ECU upgrade and keeping the open exhaust, you need some sort of a boost controller.

my first fd, i had put on a pettit downpipe and midpipe and had alsready had a apex gt spec exhaust on, mind you this was all without a fuel controller or boost controller, yeah i know i was stupid, and this was years ago like in 98, but anyways mine was spikin, i think it was spikin and not creepin, to 19 lbs, and i think my motor was going pretty fast, it still ran but not like it used to, so my advice is before you think about doing a full exhaust mainly midpipe, i would make sure you have a good fuel and boost controller, power fc for one,

will putting the cats on slove all my problems?

I have a dwnp,resonated mid, and a RB catback and
had spikes on transition.
All it took to cure it was a 2 1/2" stock metal gasket
between the dwnpipe and midpipe.
I have an old EFI purple piggyback computer that
controls boost though.

You can still have boost spikes with a cat in place on the exhaust. Spikes and creep are different as I explained above.

I understand the differences between it spiking and creeping.. The car spiked.. Will putting the cats back on solve my problems, thats what i need to know.. Im trying to get the car back reliable so i can sell it..