I've learnt plenty from being a member of this forum so thought it was time to give some info back in terms of learning.

There are a couple of threads available on Boost Controllers which is the basis for the exhaust mods I've now got on my car. https://www.rx7club.com/forum/showth...hreadid=203040

After putting on the MP and the boost controller, we (FD-Kai Wellington lads) did some AFR testing with a wideband O2 sensor as it seemed that there was still plenty of fuel in the mix, the results looked like this ..

The sections of the run at WOT in 2nd and 3rd (numbers 25-42) show the AFR in the mid to low 10's with the odd dip into the high 9's ... so no shortage of fuel! Given that under that set-up the boost was so stable it seemed logical to go the next step.

Yesterday we put the DP on, boost still remains rock solid at the 11 psi I've got it set at, the trasition has got even faster again - now to the point where it almost doesn't exist, the boost guage literally just has a momentary flicker.

Putting the G-Tech on and doing a RWHP test was the next logical step ... we've checked the accuracy of the G-Tech against 1/4 mile times and happy that while it's not a dyno the test method we use gives good accurate data that is very close to and much cheaper than going to a dyno after every little mod ... the number 266 RWHP!

We'll do another AFR test (in the near future) with the exhaust now fully opened up.

This comment would fly in the face of conventional wisdom but - it's now possible to run a full exhaust with stock ECU .. just gotta keep that boost controlled, so thanks again to Damian for designing the control set-up.

Cheers
Shaun

 

.. not even 1 reply/comment??

 

Congrats! I can't wait to dyno my beast...

 

I don't understand your graph. What is the x-axis? RPM/100 is the only thing I can think of, but then it would stop at 5700.

And if the y-axis are the afr's, holy good god. I see plateaus at 19! Someone please explain.

 

It looks like your AFR's are ridiculously high... Maybe I Missed something. If not, you are going to grenade your motor...

 

The 19 is when he backs off the gas between shifts. My Techedge reads as high as 25 on the Supra when I momentarily lift off the gas. I'm going to install the wideband on the RX next week and see if I can turn up the boost to 1.2 bar with the two additional injectors in the Greddy elbow. We run 98 octane in HK

 

If I'm reading your a/f ratios the car is very lean.

If you used a G-tech for the rwhp reading then don't hold your breath. It isn't good at measured rwhp.

The stock ECU will take many mods as long as the boost doesn't go above 10-11psi. Over that and you'll see it leaning out.

 

no no no, He wasnt flooring it during all of that. AS he stated the floor was between 25-42 where the A/f Stayed in the 10's which is really rock solid safe. The spike was when he shifted to 3rd gear.

 

That's great news. I was planning on testing the same thing, you're just a few months ahead of me. So how did you get the ECU to fuel up? Are you tricking the map sensor, or are you just relying on the overly rich stock maps?

Is this a local model (with pre-cat) or an import (no pre-cat)?

-pete

 

Nice!

However, hate to burst your bubble but Wade has already reported this type of info with a few more setup variations:

http://www.newwave.net/~flanham/wlan.../3modrule.html

The problem most people have is keeping the boost levels around stock. Still, thanks for the info!

 

I have run a dyno for three years, your car is way to lean. Best advice is 4400 and up stay out of it. Your going to break some stuff. A/F 12.00 is the most you should be pushing. You need a pump or injectors with that A/F ratio.

 

Did people not read what I posted stating the obvious and where HE typed saying at what points he floored it? the guy is running 10/1 AF and sometimes even 9!! thats awsome, almost too rich!

 

The sudden spikes to 19 and the like are common like he said. I have a datalogit and wideband on my car so I am constantly looking at these graphs. Shifting and anytime you let off the throttle are inevtiably going to spike your AFR's up sky high. This is not an issue and is normal.

That is why a graph like that is much less useful than datalogging the actual RPM vs Boost. If he had a table like that you would see likely that those high AFRs are confined to those spots where the throttle was let off and the areas that really matter are as he stated running 10's which is way safely rich.

David

 

911GT2: X axis is just a time counter, Y axis AFR ... we got the data by logging the voltage from the Wideband o2 sensor then converting voltage to AFR.

Mahjik: Thanks, I have read Wade's site .. one of the reasons I was keen to try this .. the only thing that I'm really trying to reinforce is that you can control boost very well and cheaply to boot .. and take the horsepower gains through letting her breathe.

RX-7$4$me: Exactly!! ... thankyou

 

I was just curious as to what weight you entered into the gtech meter for the HP test.

I'm not sure of the exact weight of my touring FD with me in it and a quarter tank of gas, but would like to know if anybody has an idea. I have a gtech meter as well and enter 3040 lbs as a car weight guess for my gtech meter HP runs.

 

Oh, one other? What 0-60 times are you seeing?

 

I recall getting upwards of 276+ RWHP on a Dynojet Dyno with a stock ECU, mp, Greddy catback, and Pettit intake. I was able to run sequential and up the boost with different pill sizes. Adjusted the pill size to run the boost up but just below fuel cut, which means on the first cold day or night of the year the car would hit fuel cut and a pill change was in order. Scary feeling to be blasting up the rpms and hit fuel cut all of a sudden ...

 

rpm_pwr: It's a JDM model without the pre-cat, just the heat sheilded 21/4" pipe, well it was before it got the full 3" treatment anyway.

greg: 1300kg, with somewhere between 1/4 and 1/2 a tank with two people .. we always use the same set-up and the same bit of road to keep the numbers meaningful .. haven't bothered with 0-60 times yet.

 

twokrx7: yep, it's a nasty feeling that boost cut .. hit it a couple of times when dialling in the boost controller .. wonderful thing about the ball and spring controller is that it's NOT temperature affected ..

 

i just bought the same manual controller setup b/c of this thread
ill be running a full exaust, intake, and ecu

 

Outstanding ... you'll love it!

 

I got the same dyno numbers as you with basicly the same mods. I had Petit dp, mp, and Racing Beat catback. The ECU was stock and boost was at 10 lbs. I did the same thing with changing the pill until I installed my Profec-B.

 

i am running straight through exhaust and intake, i have a boost controller and my boost is at 10 with the stock ECU and i have no problems

 

Its like I've always said (and Wade has shown on his website). You wont pop your engine from running lean if your at 10psi. You pop it by letting the boost go to high

Nice work man!!!

STEPHEN

 

checkout KDRs car, they are getting 320rwhp and 321lb/ft of torque on stock ecu and stock everything except catback exhaust!!!! Oh yeah, and they are running 87 octane.