Does the Mafless tune work well for a track (road course) cars ? Specifically a 20 min D/E type of format ?

 

POC GT1 winner last few races with our By Design/TiAL 2468 kit - Cobb tuned MAFless with filters on the turbos

 

It's a neat car. They were parked in the garage next to us at COTA this past weekend. Any chance you can get their lap data from Friday (3/3) Sam? Specifically their best Friday lap. I ran Friday but not the weekend. I'd be curious on what their speed was on the two long straights. I'm sure they would have higher speeds through the turns as they are 200-300lbs lighter and on Pirelli slicks while I was on NT01s but based on the listed lap time they would have had to have been significantly slower on the straights, unless the car was not running right. Based on their lap time something does not look right.

If they could email you a file I could do an overlay with my lap and post up the comparison. I don't mind divulging my data, it's certainly nothing impressive as it was my first day at COTA. I know some guys get secretive about their data so they may not give it up and I understand.

Thx Sam, and hope all is well on your end!!

 

I want a street version of that car. Bad-A!

 

Hey John! Doing great here same to you my friend. I actually wanted to contact you when I saw you post you were out there. They had fuel pick up and pump issues so the car was basically sputtering all the way around the track. That's why he kept coming in after a couple laps. It was really hard to figure out because the car is sort of have standalone with motorsport ABS, AIM dash and stuff but still running the stock computer on Cobb. We are lucky Gene didn't blow her up he's aggressive LOL. We're thinking about building another one. I'll give you a call. Having some nice chats with Dwayne about next level options too. The thing has a lot of potential being that it's on a stock motor and everything right now besides turbos and IC's and it's run two seasons. It ran a 1:22 at big willow before the JRZ's!

 

Ok, that makes sense. I suspected something was not right. That explains it. I saw them run down the front straight a couple of time and the car sounded fine so I wasn't sure. I'm not sure I would have taken a car out with fuel pump issues. That's ballsy.

I had fuel issues down there myself. As soon as I unloaded the car and started it up on Thursday I got a low fuel pressure alarms with idle pressure at 2.9 bar. Idle fuel pressure would cycle between 2.9 and 4.0 bar as the pump would automatically go to 100% duty cycle due to the low pressure alarm. My initial thought was "crap, the fuel pump is going out" but we soon realized that the low pressure was being caused by the greater vacuum (created by the engine when idling at a much denser sea level altitude) pulling the idle fuel pressure down. My normal idle pressure at my local 5200' is 3.2 bar. We simply upped the idle fuel pump duty cycle an additional 10% and all was normal again. You gotta love Motec....

 

It's funny Kerma our issues are because it is a stock 996TT ECU and can bus. The only thing that works on the cluster is the fuel gauge haha.

John, Dan is bad at logging and the turbo duty cycle was set at around 40% so we could play with it. Issues started after a few right handers and when it warmed up every time out. Confused us because it won at the last race at Willow all good. So we got a mobile dyno at the shop yesterday so we could log and wasted the entire day playing with it. In the pursuit of using a street car to be a full race car we slowly removed more and more from the cluster and harness. Now too much and the can bus is just not happy. Either we put stuff back in or it's Motec time exactly! After everything is disconnected even on a modded GT2 file the car still knows it's only spinning the rear tires and freaks out. We think moving fuel to the AIM and ditching the cluster may do it but eh. So not sure if t's fuel or ECU issues or both that was acting up. So temped to take it on the 170 just for a quick log but that would not be good if we got bagged. For what it is it's a beast. Cobbled together from a fire car and spare 996/997 cup parts. Can't wait to go next level.

 

That's interesting Sam. Something is up for sure. There should be no issue running the factory 996TT ECU (it's the same exact part number as a GT2 ECU). I'm running a factory ECU without any problems whatsoever. My Cup ABS is K-line based so it's no longer on CAN. Works perfectly and any error messages that would pop up relating to ABS are fed into Motec and show up on the Motec dash. Motec dash gets the rest of it's information from CAN along with a number of external sensor. Our external sensors are comprised of oil pressure, fuel pressure, fuel quantity and gearbox temperature. We are also prewired for O2 sensors and brake pressure. It's a pretty seamless system and works perfectly with the factory ECU. The car does actually does not know the difference as the engine is controlled strictly by the ECU, not Motec. I have a GT2 instrument cluster and everything works on it except all the stuff thats been moved to external sensors: oil pressure, fuel quantity, speedometer, and odometer. Again, no issues there.

For fuel pump control we are bypassing the stock set up and powering the fuel pump via the Motec DHB pwm on demand controller. The pump is wired directly off the battery through the DHB and is infinitely configurable through the Motec dash. In our case Motec is looking at rpm, boost, and throttle position to determine the duty cycle for the fuel pump. The are many safeties that can be programmed in, the variations are limitless. Works beautifully.

His car is a TT, not a GT2, so why run a modded GT2 file? What's the reason for that? I'm not sure there is any difference actually. Why not run a file that is matched to his VIN and ECU? The ECU is the same part between both the TT and GT2 anyway. I'm running a file that is matched to my VIN so technically a TT file and I'm running a GT2 cluster. The only difference between the TT and GT2 cluster is different fuel tank calibration and the lack of PSM logic in the GT2 cluster. As such there are no PSM warnings as the GT2 cluster is not "looking" for the PSM input on CAN.

Just thinking out loud as there has to be an obvious solution to the issues he's seeing. It'll be interesting to see what you guys come up with. Bottom line is, if the car was running good before, it should still be running good unless something failed.

 

Yeah I hear you. Somewhere along the lines they cut too much out of the harness so we just tried everything we could to get it to be happy 2WD. It actually drives and runs but in certain circumstances there's a signal confusing the car. There should be no reason it would limp out on 2WD dyno and some really clever guys are scratching their heads. I got some good information on what types of signals and data the computer uses and looks for. Too much has been intercepted I think. It is the later X50 so there might be a little quirk in the can.

 

Yeah, something is not right. When I put my car on a 2wd Dyno the only thing I get is an ABS fault due to the front wheels being stationary. It goes away once the car is rolling on all 4 wheels. From the cars perspective, 2wd or 4wd should not make any difference as it's a purely mechanical system with no electonic interconnect. The car has no idea whether the fwd system is installed or not.

Sam, you might try to contact Viperbob. He's on rennlist. Good guy, does a lot of Cup stuff. I spoke with him a couple of years when I was converting to a Motorsport ABS. He did the same thing on a race prepped TT a while back and if I recall correctly he said they ran into issues when they went to a maffless set up. Sounds eerily similar to what you guys are dealing with. I do not recall the details as it's been a couple of years of if they found a solution to it or not. Might be worth a shot reaching out to him.. Good luck.

 

Cheers

 

Are you able to leave the stock plastic piping in place while running these? I am looking for a filter that I can go back and forth with the stock tubing if necessary. Thanks.

 

Yes.

 

So when one leaves the stock piping in place, do you have to block off anything?
Obviously you can take the stock airbox out and block/cap the area where the accordian pipe is(right after where the MAF was). What happens to the 3 ports that are on the stock piping? There is one that is at the bottom of the DV's dump into. The next port is where the oil tank vents into and the last one is on the pipe just before the driver turbos. That one goes to the #16 check valve. What do you do with those 3 ports?

 

Good Questions, maybe someone will chime in with some info on this.