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Maybe I've missed it (though I feel I've thoroughly perused this...), but what did you do as far as the coolant pipes/fittings? Did you weld/pin/cup-car-reglue?
Wonderful build all around. Almost makes me want to do this vs buy a cup car.
John - were you able to get everything you needed on the 15 output PDM ? I feel like if I had planned better I could have got away with less but am using most of the 32 outputs on my Aim unit.
Apologies in advance if I missed the above being covered elsewhere.
John - were you able to get everything you needed on the 15 output PDM ? I feel like if I had planned better I could have got away with less but am using most of the 32 outputs on my Aim unit.
Apologies in advance if I missed the above being covered elsewhere.
Hi Jason, I don't remember Chris having any issue with making it all work with the PDM15.
I’ve been super busy over the last couple of weeks but finally getting a chance to update this thread. We finally got the car out on track to start testing and basic set up 10 days ago with both Chris Cervelli and Johnny Brewer armed with their laptops and support equipment. I figured this was going to be a very long process full of hiccups as we essentially rebuilt the car from the ground up. I couldn't have been more wrong. The whole process has been incredibly smooth and has progressed much better than any of us anticipated.
The first order of business was for Chris to start validating all the Motec engine mapping that he wrote from scratch for this application. The ECU contains 10 different power maps based on torque increasing from 300 ft.lbs to 750 ft.lbs in 50 ft.lb increments. These are all selectable on the fly by a simple toggle of the column stalk. We began methodically by running a 20 min track session in the car starting with the 300 map and working our way up from there. After each run, Chris would download the data and then look for any areas which he would tweak and reload to be validated with another run. The car spits out a huge amount of data, on the order of about 150Mb each 20 minutes. We progressed in this fashion over the next two days at the track working our way up to the 600 ft.lb (860whp) map. On the second track day, we essentially ran the car straight for 4 hours only stopping to download data, refuel, and swap drivers. Chris and I would alternate sessions over 4 hours of near continuous driving. All in all, we were both surprised how close to the bullseye Chris’s tuning was since it was all done on a dyno with only very minor tweaks needed under real world track conditions.
Overall, everything was a resounding success with us validating all the maps through 600. The engine and gearbox performed absolutely flawlessly without a single hiccup in over 5 hours of hard driving at race pace in near 100F track temps. The small Tilton 5.5” Carbon RSR clutch is absolutely amazing and completely changes the way the car can be shifted. There is absolutely no comparison between this clutch and the Cup clutch I ran in this car previously. This tiny feather weight clutch is a total winner. The Chillout system performed without a hitch keeping me cool and comfortable all weekend. This is virtually a must in a car without any air-conditioning. Thumbs up all the way. One thing that literally blew me away is how much cooler that car ran compared to the previous set up. Putting down 860whp at 1.0 bar boost, the engine ran approximately 25-30F cooler in both engine coolant and oil temps reading roughly 205F and 235F respectively. Previously we were seeing 230F on coolant and 265F on oil when the engine was putting down over 80whp less on 1.3 bar boost. The only difference being the Motec ECU v. OEM ECU, 47mm headers v. OEM headers, XR1000 turbos v. XR980 turbos, modified OEM airbox v. stock OEM airbox. The drop of 30F is absolutely huge and allows this car to easily run hour long races without limitation. The reduction of back pressure of the substantially larger headers coupled with the larger XR1000 hot sections bore fruit. The superior computing power of the Motec ECU along with Chris's tuning allows us to safely run much more aggressive timing which also contributes to lower engine temperatures. A huge win there. The infinitely variable variocam completes the package.
After running the car for the first time, my first response rolling back into the paddock and getting out was “Now this is a real f****ng race car!” It felt absolutely amazing. Both the engine and gearbox are fully hard mounted to the chassis and the whole package is very communicative. Although we haven’t really started dialing the chassis, it is at a very solid starting point already. Chris made some changes to the shocks and the rear wing AOA after some of his runs and that was a real solid improvement. We initially ran the car on a set of old Pirelli DH slicks that had 5 sessions on them and all the time we put on them on the dyno. They lasted another 6 sessions during the first day before finally the rears gave up. The following day we put on a set of brand new Yokohama A60 slicks on which Chris managed a blistering 1:47.4 at HPR at a medium 500 ft.lb map (650 whp). To put this time in perspective, this is almost 20 seconds per lap faster than what a typical modded 996/997TT will run at this track at about 2:05 on DOT track rubber. The Yokohama A60s were absolutely amazing compared to the Pirelli DH slicks we ran on this car previously. The Yokos absolutely made the car feel like on rails and had a very progressive breakaway compared to the Pirellis. We put 11 sessions on these tires over the next day and they were still very manageable although over 2 seconds slower by then.
Anyway, that completed our first two days at the track. It went so well that I decided to take the car and run it during this past weekend's NASA race event to get some more seat time and data for Chris to look at. I ended up swapping the now worn out Yokohamas for a fresh set of Pirelli DHs. What a huge surprise it was to realize how much inferior these tires are compared to the Yokos. Although still brand new (after having been in my basement for 4 years), the Pirellis felt downright numb in comparisson and were only marginally faster new compared to the nearly worn out Yokos. I spoke with a Pirelli rep at the event and they confirmed that the compound on those particular tires was not very good and had been changed by Pirelli 3 years ago. They no longer make these tires in my sizes so it’s a moot point as we will be setting the car up to run N-spec 27/65 and 30/68 Michelin Slicks.
Regardless of the tire woes, I got some great data and some badly needed seat time to give me a chance to get acquainted with the car again. I felt much better by the end of the weekend. Overall the car performed flawlessly with the casualty being a bad battery cable which has since been replaced.
The next item on the agenda after running the car now for 4 days at the track is to finish up validating the 650, 700, and 750 torque maps which we have not run yet. I anticipate the 650 map (920whp) will still be very useable when trying to maximize performance while still being easy on the engine from a wear and tear standpoint. Anything beyond that is likely would only be used for a Time trial run. After this is done, we will start dialing in the suspension. The 1700# front and 2100# rear springs felt fantastic and will remain unchanged. We are however going to swap in different tender springs in the front with a lower block load to reduce some weight transfer during accelaration. I called my Eibach rep and have those in the mail already. The car is also going to be lowered approximately another 5mm on all 4 corners. I did have the car officially weighed at the NASA tech impound and it came in at 2832 lbs ready to run with 10 gal of gas without driver.
Anyway, here is a quick video of a couple of hot laps on Saturday on the problematic Pirellis. Below that is a link to a test and tune session on Friday on the worn out Yokohamas which was actually the better tire overall. In that video you can see the closing speeds this car has on other traffic that was present there for the NASA weekend. Both videos should be selectable at 720P. Many thanks to Chris Cervelli and Johnny Brewer for all their hard work up to this point! Cheers!
I also like what you have done with your windshield wiper...
The stability of the water/oil temps is immensely impressive with very little spread.
There is just a single wiper set up to sweep the bulk of the drivers side. Yeah, the temps are low and super stable. Even the gearbox stabilizes right at 200F. It’s night and day to the previous set up.
08-11-2023, 09:03 PM
