I have had this problem since I finished this build.. But my car does not start to boost well until about 5K+ RPM's. I read posts of people with similar setup's saying they hit 10 PSi in 2nd gear at 3k!!! I have been searching and searching for a problem but everythigg checks out okay. I have checked the wastegate operation a trillion times, so it has to be somthing besides that.

I am open to any and all causes of this.

Mods listed in Sig. On the dyno I was boosting over 13PSI at 8.5K the high end boost is great! And it was still not dropping off. I just don't quite get why I have such weak low end boost.


Thanks,

Robert

 

maybe its your primary and secondary's being to differnt. because i know a guy with the simlar setup but hes just running avcr instead safc but he has a FMIC and hes only running 800 secondary's only and his runs fine

 

I am still runing the stock IC, but if anything this should increase boost responce. I keep thining about a aftermarket IC, but I need to figure out whats up with this first.

I don't think the injectors are a issue; I played on the dyno for 2 days (infact I will try to post pics of the boost curve on the dyno later, I am at work right now) And I have the fuel curve dialed in perfect, that should be the only thing the injectors would effect, I assume.

 

Here is my day 1 Dyno sheets. Notice the low end boost. I ended up with much higher boost after I set my second stage boost control config, But the curve is about the same (still looking for my day 2 sheets, I will try to post them also)

 

1. compression
2. exhaust
3. check to make sure you have the air diffusers and all the little nefty stock gadgets that mazda put there
4. check for leaks

but its most likely going to be number 1

 

More details, and lots pictures of the problems in this link

Check this post

I know it's not motor compression ... the motor only has 2600 miles on it, and I have a compression gauge.


I am very lost on this problem, there is nothing on this car I have not been able to solve ... until this.

-Robert

 

Take a look at your exhaust... I had the same problem when i went to a big turbo.... Make sure the gaskets are good and not leaking.... Make sure everything is flat, and tight. I didn't gain hp, but my torque band got really wide. like this

 

what where your compression results?

 

Compression was mid-high 90's with very little fluctuation. 3 even bumps per rotor.

 

I have the same problem with boost. I know its from huge exhaust leaks cuz i can hear them. I also have a streetport which could be adding to the problem, cuz the engine could be outflowing the stock turbo. I make about 3psi MAX in first, in second it makes only 3 till about 5k, then goes up to 6.

 

Well, thats one thing I have not really checked is the exhaust gasket. But when I installed the turbo i torqued it to spec, with a barand new gasket ... i will double check that in the morning. I just put my UIM all back toghther today, I have taken just about everything apart at this point looking for the problem

Question; at what point does your TII gauge go from vacuum to 0 (equal pressure) My guage shows vacuum till past 3k. .. then it just starts to get to 0. then finally boost .... I boost great pressure 10PSI+, but it ust kicks in so late i have to shift once it starts to boost good ...

 

Check your other thread and please try to link duplicate threads

-edit-
https://www.rx7club.com/showthread.p...hreadid=231522

 

Sorry, wasn't sure what section would get a more productive anwser... infact i forgot i posted it there also, i need to check the replies.

thx.

 

what a second!!! you still have vaccum till 3k!!?!?!?! check to make sure your throttle body is opening all the way please....

 

Make sure the wastegate flap is tight as well-

 

you have a cat? could be plugged. make sure your car is "breathing" properly.

 

No cat, Free flowing 3"-4" All the way through. I still have the problem right now. But at the moment I have the whole UIM, and half of the rest of the car apart, I am starting back over from step 1 if you know what I mean.

-Robert

 

Secondary throttle plates not opening all the way/all the time.....dittos of an above post.

 

I have the whole UIM opened up right now, I don't see anything wrong with the throttle body at all. I did have the TB mod done.. where the first set of plates are removed, I am in the process of putting that back to normal. It is NOT the wastegate, trust me, and I have looked at almost everything on this situation.... this is by far the most stuped I have ever been with this thing .


-Robert