GT35+AEM+264's = Good pump gas Dyno

[MRSUPRA]

Dynoed on thursday on the local hearbreaker mustang dyno. Before I get to the numbers, this dyno reads 14-16% lower than a dynojet.

Final numbers: 431rwhp 401rwt. If you do the math, that's about 495rwhp on a dynojet.

This was on 93 octane with 17.5psi and 15 degrees of timing. Plenty conservative. My tuner was confident that I could easily hit 500+rwhp on a dynojet on pump gas with a little bit more boost and/or some more playing around with the cam gears. For comparison, on my old 7M with the stock ECU, I hit 511rwhp at 24psi with C16.

The GT35R is a great turbo. As you can see, with the right tuning it is very efficient at low boost, while providing quick spool in any gear. Exactly what I was looking for.

As for the AEM. It was a tuning nightmare on my 7M. I don't know how AEM can justify charging $1600+ for a system with so many quirks. A huge thanks goes out to Sean(X-man) for helping me get things dialed in and wiring in the 3000GT igniter and sequential injection. Also a thanks goes out to my tuner Sal who really knows the AEM inside and out.

Matt

 

[empera]

nice numbers man! congrats, any dyno vids? or sheets? i really need to get my aem tuned.

 

[MRSUPRA]

Thanks. I will post a sheet and possibly a video when I redyno on a dynojet. The gragh is not layed out like it should be making it hard to see the RPM's and power. Not to mention they were 3rd gear pulls making it look a little laggier than it would be on a higher load.

 

[chevyeater]

Sounds like the torque is off a bit but, if the correction is as far from a DJ as you say then, good HP numbers.

Who tuned it?

 

[X-man]

Nice numbers. I would add some more timing. The numbers should really jump then.

 

[MRSUPRA]

The guy who tuned (Sal) has done a lot of AEM tuning on Hondas and Mitsubishi's, and a couple of 2JZ's. THis was his first 7M.

As for the correction factor. I asked Sal and the dyno owner several times how really low this dyno reads and they kept saying they have seen other cars in my power range pick up 60 to 70 rwhp by going to a dynojet with no changes.

The car is going to be fine tuned further. The dyno was costing me $100/per hour plus what I had already payed my tuner and my wallet was feeling a little too light after 2 hours.

 

[MRSUPRA]

My biggest problem now is that my 680cc injectors are running around 90% duty cycle for some reason . I'm not sure if it's because I'm running sequential injection, because theoretically 680's should be plenty at this power level.

Until I figure this out, I won't be able to do a race gas tune.

 

[Supraholics]

Can you post some pictures as well? I don't think I've ever seen your car or your engine bay.

nice numbers man! congrats, any dyno vids? or sheets? i really need to get my aem tuned.

 

[X-man]

Bring it down here. We'll do all the dialing in you want.

Sean

The guy who tuned (Sal) has done a lot of AEM tuning on Hondas and Mitsubishi's, and a couple of 2JZ's. THis was his first 7M.

As for the correction factor. I asked Sal and the dyno owner several times how really low this dyno reads and they kept saying they have seen other cars in my power range pick up 60 to 70 rwhp by going to a dynojet with no changes.

The car is going to be fine tuned further. The dyno was costing me $100/per hour plus what I had already payed my tuner and my wallet was feeling a little too light after 2 hours.

 

[MRSUPRA]

Hey Sean, I might take you up on that. I figure it would take me 3.5 hours from my house to your area.

 

[X-man]

Hey Sean, I might take you up on that. I figure it would take me 3.5 hours from my house to your area.

I can't see how the injectors are maxxing out at that low of boost on a 61 mm turbo. I also checked my timing at 17 to 19 psi and I'm running 21 to 22 degree's under boost. Just let me know and we'll set something up.

Sean

 

[MRSUPRA]

Yeah at just under 500rwhp, there is no way I should be maxing out 680cc injectors. Unless somehow the sequential setup is using them up.

 

[rumptis]

I have heard of the 15% mod before....lawlz

Nice job.

 

[X-man]

Yeah at just under 500rwhp, there is no way I should be maxing out 680cc injectors. Unless somehow the sequential setup is using them up.

Sequential Fuel Injection vs. Batch Fire Although these are not physical injector configurations, the manner in which injector pulses are dictated is very important to engine performance and environmental variables as well. A sequential fuel injection system triggers one injector at a time following the firing sequence of the engine. Batch fire systems trigger multiple injectors simultaneously, sometimes grouping cylinders to receive fuel in “banks.” Due to the fact that batch fired injectors pulse more than once per cylinder cycle (usually twice), only half the fuel is delivered at a time. Essentially, the first pulse of fuel is fired with the intake valve closed, and then a second pulse is released just when the valve opens. SFI systems are more precise and optimize all engine performance characteristics, although such systems require more involved electronic controls.



Þ Sequential, multiport fuel injection (SMPI or SFI) is the most sophisticated means of fuel delivery as of now, and many newer vehicles are equipped with this system.

Usually sequential injection yields better fuel mileage. The advantage is you can move the injector phasing around to see if this has any effect on how much fuel you are using and why you are having to pulse the injector so long. It is possible the cams or cam timing might be effecting this also due to to much overlap. How are you measuring your duty cycle?

Sean

 

[IJ.]

What's the base fuel pressure?

 

[X-man]

What's the base fuel pressure?

That was my next question. I run a base fuel psi of 36. When I switched mine to the sequential injector control where I could set the injector phasing I don't remember having to make any real big changes in the fuel map one way or the other.

Matt how is the driveability with the car? This was one of the biggest reasons I changed to this set up was to help cure the quirks the AEM seem to have with the MKIII ignition system and how it effected driveability.

Sean

 

[IJ.]

I knocked my base down as low as the Aeromotive AFPR would allow so I could crank in some more idle duty with the RC1000's in sequential as I was finding the idle would go a bit sketchy on hot days.

I was a bit surprised that no one had asked what his base was

 

[X-man]

I knocked my base down as low as the Aeromotive AFPR would allow so I could crank in some more idle duty with the RC1000's in sequential as I was finding the idle would go a bit sketchy on hot days.

I was a bit surprised that no one had asked what his base was

There are a few things I'm curious about. What was the a/f ratio tuned for? What was the engine revved to, higher rpm at the same power level will raise injector duty cycle or amount of fuel needed to turn said rpm? Of course base fuel psi being to low will cause you to have to raise the duty cycle to compensate for low psi, and even timing being to retarded can cause issues with combustion and fuel being used.

Sean

 

[IJ.]

Sean: Yep a stackup could possibly cause him to run out of injector at that power level with the 680's (I'm still learning this Petrol thing so this is all interesting)

 

[MRSUPRA]

I love this tech talk.
My base fuel pressure is at 41psi. That is with the vacuum connected to the fuel pressure regulator.
Also, I'm reving out to about 6900rpm's on the dyno. AFR's were mid 11's and higher with some lean spots we could not get rid of. We then realized I was running low on fuel, so I put about 5 gallons in and got the AFR;s better, although I left with 10.8 AFR's. The injector duty cycle was still over 90%.