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-   -   Intake (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/intake-318309/)

Terrh 06-17-04 06:04 PM

Intake
 
Soo... I finally get sometime to do some work on the car.

I go to the exhaust shop and fix my ghettoass midpipe, and I install my boost gauge. Car boosts fine to 5.5 PSI.

I decide to make an adapter for the AFM so I can install a cone filter that I've had lying around forever... It's pretty neat, with that mesh screen thing over the end for extra airflow.

I made an adapter out of a CB radio bracket and an old piece of exhaust pipe. It looks ugly, but it works :).

I use a 3" to 2" rubber plumbing adapter ($14.95!) to hook the MAF directly to the turbo, and I attached it all with hose clamps and zip ties. :)

I took the car for a drive after.. WAY nicer midrange at light throttle (fixed exhaust maybe?)... boosts to about 6PSI in 1st, 8PSI in 2nd, and 12PSI in 3rd, 4th, and 5th.

is 12PSI too much boost? there is NO ping... I'm running 91 octane.

car feels SUPER quick.. I'm lovin it.

J-Rat 06-17-04 06:37 PM

I personally used to run to 12s on the stock turbo, but I had 720s and an SAFC. On the stock fuel system, I wouldnt recommend it.

Terrh 06-17-04 06:45 PM

is there any way I can lower the boost? My wastegate is allready ported...

J-Rat 06-17-04 06:48 PM

If your CREEPING to 12, then nope... Need to port bigger, or put some sort of restriction back in the intake/exhaust to limit boost. Whats your boost controller?

Terrh 06-17-04 07:18 PM

boost controller? what's that?

boost is set at stock.

I don't think I'd call it "creep" because its basically 10+PSI instantly.

J-Rat 06-17-04 07:36 PM

If your boost is stock, then your wastegate should be opening at 5.5 (or so) PSI. IF you werent creeping, your boost would stay at 5.5. Since your going to 12 PSI and you have no boost controller, you are creeping.

Not to sound mean or anything, but given the questions you have asked, I would put your stock intake back on, and educate yourself before you blow your motor.

Terrh 06-17-04 07:40 PM

I meant, is there any way to prevent the boost from climbing while keeping the intake..

if I blow the motor I'll put my spare in.. this one has cooked oil seals anyways.

I was under the impression that creep "crept".. like if you stayed WOT for 20+ seconds then it would gradually climb. That's what it did before the intake.

why would I blow the motor anyways, as long as there's no ping it's safe, right? EGT's aren't too high...

J-Rat 06-17-04 07:54 PM

Creep occurs when the wastegate cant keep up with the amount of air the exhaust is flowing. Your turbo has a naturally in-efficient wastegate. But we all knew that.

Creep can happen instantly. Anytime the wastegate cant keep up.. Call it a creep, spike, whatever. Either way, you do NOT have positive control of your boost.

2-ways to control this. Put your intake back on, or port your wastegate even bigger. That it. No boost controller in the world can control creep. Oh, you could put your stock exhaust back on too, that would work.

And your correct, you might not be pinging. But you dont have any safety margin either. 12 PSI on a stock fuel system is running on the ragged edge. You may already be pinging, they just arent audible yet.

If you dont have any issues with blowing that motor, yank the wastegate line and cap it off. You will get MAD SILLY boost! Wont last long though...:)

Terrh 06-18-04 06:24 PM

my stock exhaust is WAY more open than this one.

stock dp - 18" hole - rest of rusted ass exhaust.

I think (until I get my fuel pump and safc installed) that I'm going to put a piece of tape or something over part of the filter to block it to control boost.

I AM getting some detonation.. but not at WOT. I sometimes get some at low boost.. I think it may be due to my FCD.
stock boost gauge reads about 0 but my vdo gauge says 3-4 PSI.
I think my FCD is fooling the car into thinking that it's at a lower boost than it is (which its suppossed to do).. but it's doing it too much at non-wot.

J-Rat 06-18-04 06:26 PM

Yeah, but it shouldnt fool it THAT low!!! IF your gauge is only reading "0" then your not getting full fuel pulses.

Terrh 06-18-04 07:16 PM

at 2-3 PSI on the VDO my stock gauge is at or just above 0.

at 7+PSI on the VDO my stock gauge is at the +40.

I think i'm going to cut out a degree or two of timing, too.. hopefully that will help.


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