50g/s-60g/s at 10psi or so is not as big of a hole as you might think .
I know I was gaining 30ish g/s from a vac leak at the turbo inlet that was fixed just by adding another thickness of gasket paper.

Seeing as we are on this subject and it seems to be relavent to this thread lets discuss it some more .

How can you get 400g/s MAF and make less than 300whp ? I can think of 3 possibilities :
1/MAF is scaled wrong
2/Boost leak
3/Stuffed engine IE low compression

Can anyone think of any others ?

 

I think 3 might be off, if compression is low you won't move much air.

Bad timing should be added.

 

Yeah - bad timing and over rich will cut the power back but wouldn't flow suffer as well ?

I've seen 10whp lost from being over rich ie 10.5 afrs vs 11.5
With timing - I would imagine it would need to be 10-15 degrees off optimal to make a big difference ?

 

Hard to say, I've never been able to do better than 10-15 WHP on a V-8 with timing, and only 3-4 on a rotary (due to not being able to be too aggressive.

However if you run stupid retarded (like 5 ATDC at 7000 RPMS) I would imagine you would see a big dip in power.

 

Bad compression is an interesting one . More air will blow past the seals and waste power but will overall flow go down or stay the same as a heathy engine ?

My thoughts are that flow will stay the same but whp will suffer as the efficiency of the engine decreases.

 

Incorrect timing and AFR will affect power disproportionally to airflow.
Low static compression may or may not affect flow, depending on the true dynamic compression.

 

man.. i just read through this whole thing. is this mod still being offered? im not looking for anything beyond 270 hp. just wanted more reliability out the t618z

 

so for example , if you lost 10 whp due to AFR too rich -what would you estimate the airflow loss to be ?

 

8 - 15 g/sec

 

It's still being offered.

I am now only about 2.5 hours away from RX7 store and they are offering it.

We are just trying to find some more information on cars running the upgrade.

I will most likely be getting this mod but I still would like to see more proven results, and hopefully by the time I'm ready there will be.

 

Hello all.

I have this Greddy upgrade here that I have fabricated a wastegate actuator bracket for an adjustable/universal actuator. I just want to make sure that it will fit on the car w/o fitment problems.

Let me know if its a big fat negative or if its good. I can make all these brackets stamped out, I just want to get it 100% right before I do.

Bryan@BNR

 

Too far out and too low.

 

If I send you my core can I be the test subject?

 

Orientation should be like this:





Also, note the size of the diaphragm. This is the minimum diameter for adequate boost control.

 

That might be my turbo. I should have sent you the greddy actuator. Stupid me...

Here it is. See last picture for the space you have to work with. Tell me what other measurements you need and I will get them for you ASAP.

 

MM thanks for the pics and explanation. I have those actuators at my shop. Just too bulky for my taste.

I have used the small diaphram actuators for years and years. Never having problems with control. I preset the crack pressure.

I will make another bracket sometime before the end of the week and try to get it in the correct orientation so I can complete this order. I'll post pics later on in the week. I may laser cut the bracket once I get it placed correctly so it will be easy to replicate.

Bryan@BNR

 

Yes, but that is probably because you use properly sized turbos!

The pressure against the wastegate will blow open a can that has a diaphragm that is less than double the diameter of the flap, regardless of its preload.

 

/\ yep . But not when you hold it closed

 

If it is "held closed", then you have no boost control - you are just running the turbo in "open-loop", hoping it is so inefficient that the temperature delta will cancel the boost spike.

 

sorry - i meant held PARTIALLY closed not fully closed .....

 

exact. same. problem.

 

perhaps yes on most setups but not so on an upgraded Greddy . 18 months and 35000 kms of driving tells me it works just fine ......

 

It works "fine" because of the above-mentioned thermal loop.

 

I don't care why it works - just that it does work

but seeing as you mention it .

How can a turbo with the wastegate held partially closed making 10psi make any more heat than one making 10psi using a larger actuator ? When you think about it , the wastegate has to be held in the exact same position either way ..........

 

Alright. Hopefully this will work well.

Bryan