Hey!

Stock engine, fmic, pfs, 3" exhaust (from turbos), upgraded fuelpump.

After i installed a full 3" exhaust i lost my first turbo, got about 0.3bar until the second turbo is kicking in and then i get full boost..

Is this caused by a wrong timed pre-spool? is this common after installing 3" exhaust? or is it something else that could be wrong?

please give me some advice..

Thank you..

 

*PFC
No boost controller, changed wastegate pill to a bigger one, (i know this could be the problem, wastegate opens too early, but cant hold down boost with original pill)

 

Your assessment is correct - no pill in the WG line is the cause.

However, IMO, you have a much bigger problem!

The only reason you are getting full boost when the secondary comes on is that you are exceeding the capacity of the wastegate and getting boost creep (search). Boost creep is NOT controllable by a boost controller or pill change.

You are in dangerous territory - only a weather change away from blowing your engine due to the stock wastegate not having the capacity needed with a full open exhaust. You need to restrict the exhaust (stock or hi-flow cat, original muffler, etc.) and get a proper boost controller before you blow your engine!

Do some searches on these subjects and be careful - as I said, your engine is living dangerously.

 

I still have a pill in the wg-line, but a slightly bigger one, and i can get a stable 0.8bar boost.

A bigger/ported wg is recommended with a full open exhaust generally?

 

I have a ported w/g, while I see everyone recommending it to others, it does absolutely nothing for me, I can't control my boost at all. Doesn't even creep, just shoots right past my high boost setting.

 

Yes. Unless the WG is ported, it can't control boost with an open exhaust.

And with the stock ECU (at least with the ones I am familiar with - the US '93-95 version), you need to limit boost to 10 psi, or you will get fuel cut per the attached table.

 

Maybe you have a boost-controller problem?

Dave

 

Yesterday i ran my rx7 on a rototest dyno.

My boost problems just vanished, no boost creep and a stable 0.85bar. (full exhaust, stock wg-port)

Had no time for tuning, just ran my street tuned inj map.

Couldn't go further than 6500rpm with my stock injectors (85% inj duty)

it made 286rwhp and 354nm at 0.85bar @6500rpm (afr mid 11)

Putting in bigger injectors now.. what do you think we will see at 7500rpm?

 

Someone told me that if you go with a highflow cat or a straight open midpipe youll get boost creep unless you have a boost controller or a aftermarket ECU to change the boost settings. I have no idea if this is true or not, but im about to go high flow cat and a open exhaust, should i have a new ECU before i put the highflow on?

 

people way overreact to this boost creep ****....boost creep is noticable but its not THAT bad. The main thing you experience from the flow mods is insane spike that the solenoids cannot keep up with. If you unplug the wg solenoid electrical connector, it doesnt matter what pills etc...it will keep the wg open at all times and ull notice aboue 1lb-2lbs MAX creep...thats if you car boosts over 7psi at all enough to make the transition..creep also only occurs up high in the rpm range

the pills/midpipe etc should not affect the primary turbo in anyway besides lower the boost to 7psi max....about the creep just keep the boost set at 7.5-8psi so that u hit 10 by redline and wait until u port the wg to turn the boost up to 10 across +

 

Hitokiri_Gensai: I am not an expert by any means. But I think the safest bet for you would be to install an aftermarket ECU before opening up the exhaust any more. Otherwise you run the risk of a fuel cut if (when) you boost over the limitations of the stock ECU.

just my $.02

 

This is a gross over exaggeration of the problem. The amount of creep will vary between cars and setups. Some cars can creep up to and/or over 17 PSI.

It can also be boost dependent. i.e. if you have your max boost set to 11 PSI, there may not enough flow to overwhelm the wastegate, however at 13 PSI the increase may be too much and the car experiences creep. So, setting the car to 7 or 8 PSI may not demonstrate any creep at all.

While I do believe people freak out too much over creep (or possible creep), it's just not quite a simple for everyone as you make it seem.

 

17psi god damn.....i must have a one of a kind engine, I was only experiencing 1 to 1.5 MAX creep in the middle of the winter running on wastegate spring pressure and only over 6k rpms

 

Not sure what you mean by "open exhaust" but generally, a hi-flow cat will not contribute to boost CREEP. As long as you stay with a hi-flow cat, even with an aftermarket cat-back and DP, you should be fine. IMO, stay away from a mid-pipe without porting your wastegate. As a side note, remember that CREEP is different than SPIKE. A boost contoller is for SPIKE, but it will do nothing for CREEP.

 

Heh Heh....your turbo's SUCK ! ! !

 

just buy restrictor plates....research it. Thats what im about to do and it seems promising.