I had XS tune my car on Friday. Unfortunately, some issues kept me from hitting my target 400 RWHP @ 15 psi. The biggest issue was that my boost would rise to 15 psi and then quickly drop to 13 due to my screwy boost control setup. So, I think my HP peak was equivalent to what I'd get at 13 psi, and the torque peak was probably about what I would expect at a solid 15 psi.

This was a good experience, though, as I was very happy with the way XS worked on the car. They really know what they are doing, and I look forward to having them tune it again after I get the issues sorted out.

Here is the HP plot:


See the torque plot and read more at my web site:
http://www.maxcooper.com/rx7/gallery...-19/index.html

-Max

 

Nice power curve. What turbo are you using???

Ken

 

Apexi RX-6 I think.

 

Good to see you made it to the dyno. You should try dropping the exhaust for a dyno run and see how much of a difference it makes. I've heard good things about the new Racing Beat exhaust ... I know my Greddy flows more than the old one.

Where did you tap for the boost control? Did you use the nipple on the intake runner or somewhere else? I have stated I don't like using the nipples on the intake run for anything other than BOV. You can ask Goodfella about the oscilliation on one of his dyno runs. You might want to order the AVC-R solenoid as a replacement for the stock solenoid.

So how is it driving around on the streets? Having any luck putting that low rpm power to the ground?

Oh well, good luck.

 

Hey Guys,

Ken, Marshall is right, I am using the A'PEXi RX6 turbo kit. It is a good kit, with high quality components, stock-like spool up, no transition, no boost creep, and slightly more potential at the high end. But it isn't a big power turbo. It is a pretty nice replacement for the stock system, except that it is louder (especially at low RPMs) and won't pass emissions.

I have ordered an AVC-R and will install it soon. I might try just installing the solenoid and hooking it up to the PowerFC as I would love to avoid adding another electronic box and display to the cockpit. However, I am kind of curious about the AVC-Rs advanced features, so I might have to put the whole thing in just to see what it can do. For example, less boost in first gear would be nice. I'll have to just run 13 psi until I can get back to XS, but at least it will be ready for the next session. I am not sure when I will be able to get back for more tuning.

The boost signal for the wastegate is tapped off of two places, as per the instructions from A'PEXi. The first place it right off the turbo compressor outlet, but they have you connect that to a pipe coming from the rat's nest and then use a T to grab the signal for the wastegate. I also tapped off this line to do my stock-solenoid setup, which perhaps was a mistake. I'll see what happens when I hook up the AVC-R.

It is great on the street. Very drivable. It will totally smoke the tires from any RPM in first gear as you might expect. My 265/40-17 S-03s hold pretty well, though, and I can use full power in second gear and up. Sometimes they slip a bit in second, but most of the time it holds. It feels great to know that it is tuned and relatively safe to flog it. Now that I can feel safe just planting the throttle, I do notice the drop in torque that comes with the drop in boost. Before I would watch the boost gauge hit 15 and then quickly direct my gaze over to the J&S to watch for knock and I wouldn't notice the drop in boost. With XS's tuning, it now makes more power and doesn't miss like it was doing before (too rich).

-Max

 

Let us know when you can get a good run in.
You are definately losing boost / power on the top.

I made right at 300 RWHP at 5000 rpms and a smooth upward curve to 417 RWHP at 8000 rpms. This was at 15 psi with the RX6 in a ported engine. I think 400 RWHP is very likely.

What are you using for fuel injectors?
Did you cut the spring for the wastegate on your kit?

Cheuk

Nevermind about the injectors, I just read your website.
How much did it cost for RC to enlarge your injectors?

 

Cheuk,

Thanks for the feedback. I would like to get back there as soon as possible, but it will be a few weeks or even months in reality. I'll make an appointment as soon as I get the boost controller installed. I have my fingers crossed for 400 at 15 psi. We'll see. I've got a restrictive (quiet) exhaust on there, too, so I don't expect the exactly the same results you got (but I would be very pleased if it worked out that way!).

$175 each for the injector service, but I think I got a club discount of $35 or something, too. I had my fuel pump flow tested at the same time.

EVERYONE SEND YOUR FUEL PUMP TO RC FOR TESTING! It is $50 for a flow test at one voltage. I specified 13.2v so I could compare the results with the Bosch pump flow data that is available, but I think I should have had them test at 12v or 12.5v instead. Maybe I'll send it in for another test.

I hope we can get a good database of pump tests from this.

-Max

 

Those are pretty good numbers so far. I'm really impressed with the A'pexi Turbo. I was wondering how much did XS charge you to tune the Power FC to your mods? I plan on having XS tune my Power FC when I go with a T-78 single turbo setup this winter.
Thanks

 

XS can program a base map into your PowerFC for about $150. That should get you close to what you want. They use the PowerExcel software to change things you cannot access with the Commander, so be aware that this is more than just punching in a new fuel correction table. XS has tuned a number of cars with different injectors and turbos, and they probably have a decent library of maps to choose from.

Dyno tuning is the next level of programming, and to me it just makes sense to get this kind of tuning done if you spent a lot of money on the parts. It runs about $150/hour at XS. XS really has the expertise with the PowerFC and the RX-7 to make this a great investment.

I know it can be difficult to find shops that can do this tuning around the country, especially considering XS might be the only company that has the PowerExcel software that is needed to adjust the basic fuel injection map and other options in the PowerFC. Hopefully more shops will get this capability in other parts of the country. I love the PowerFC, and I am really glad to be near XS for tuning. If I lived elsewhere, I would probably get a Haltech for accessibility to tuners and the lack of visual emissions tests. Or maybe I would drive to SoCal to have XS tune my PowerFC if I lived even remotely close.

-Max

 

I convinced my roomate to buy the whole Apex kit for his RX7 and I also installed it and said I could tune it up for him, but we are having a hell of a time tuning that thing. Can you PLEASE send me EVERYTHING you have in your POWERFC. I will pay for the Maps. I'd very much appreciate the help. The car is popping and doing wierd stuff.
You can email to Megaspeed7@aol.com

Thanks,
Patrick Harris

 

Patrick,

I can't send you the maps because I can't access all the information you would need to use them with the Commander.

It is very important to understand how the PowerFC works:

1. There is what is called the Basic Injection Map that is described on page 21 of the Commander manual. It represents the amount of fuel needed at each pressure/RPM cell to give a stoichiometric fuel mixture. The shape of the map depends on the various flow and temperature efficiencies of your engine and the stuff you have bolted to it. IT CANNOT BE CHANGED OR EVEN VIEWED VIA THE COMMANDER, BUT RATHER ONLY BY THE A'PEXi POWER EXCEL SOFTWARE. So, I can't tell you what mine is and you couldn't alter yours even if I could.

2. The Fuel Correction Map is the one you can edit with the Commander, and it has a cell for each cell in the Basic Injection Map that you can edit to increase or decrease the amount of fuel that is delivered RELATIVE TO THE BASIC INJECTION MAP. However, it has its limits, and most of my high-load cells were at the maximum before I installed the turbo. So, that leads me to believe that you need a richer basic injection map for running a single turbo with the PowerFC safely. Well, maybe...

3. There are some additional options for increasing the amount of fuel delivered. You can increase the amount of fuel delivered by a few percent based on RPM or MAP sensor voltage, or both. See page 24 in the Commander manual for more details. This might be enough to run the single turbo safely, but I am just not sure. There do seem to be a number of people using these methods to run with a single.

I think your best bet is to send the PowerFC to XS to get a base map from them and then take it somewhere locally to fine tune it on a dyno using the Fuel Correction Map. I know that wasn't what you wanted to hear, but I hope it helps.

-Max

 

for all of you with the apex tubo, what times in 1/4 mile would you expect this tubo to run? what size injectors are you using CHEUK?

luigi
94 fd

 

Thanks so much for the info. I kinda figured there was something up with the base map, and I didn't know that it wasn't tunable. It really sucks that APEX doesn't make one that comes with the Power FC. Especially since Kyle ordered every apex power product at the same time. Well can you please tell me where I can get in touch with XS?
Thanks again,
Patrick

 

http://www.xs-engineering.com/