DDMotorsports Redline Time Attack Round #2 Results!

M.Bonanni · 06-02-2009, 07:17 PM

Well round #2 of the 2009 Redline Time Attack series is in the books and this marks the halfway point in the season for the Street RWD West class and the DDMotorsports Project 370Z.

Unlike most teams, we are not out there this year to win these events. This year is a development year for the 370Z and our efforts with it in time attack. The main goal for this season of racing is to develop and test products for companies and see what the 370Z is capable of as a track car.

Round #1 of the series was at Buttonwillow Raceway and the car was very close to stock. At this event we did initial testing on the Mishimoto Oil Cooler kit, BC Racing ER Type coilovers, Hawk HP+ brake pads, Berk Technology High Flow Cats, SPL Parts rear camber arms and JWT Pop-Charger intakes. The rest of the car was stock. The track was technical with a lot of different types of turns ranging from low to somewhat high speed. All of the parts worked excellent with the exception of the stock limited slip differential, which as it turns out, broke at this event.

Round #2 was at Willow Springs Raceway and in contrast to Buttonwillow, this track has no low speed corners and a few long fast sweepers which really tell the tale of how your car is setup handling wise. Not to mention it was about 35 degrees hotter than it was at Buttonwillow. Between round #1 and round #2 we changed the stock wheels & tires to Forgestar F14 wheels and NT05 tires in the same size as the stock sport package wheels/tires. We also added a GTSPEC 4-point ladder brace, Nismo 60mm wheel studs, and lighter Muteki lug nuts. The rest of the car remained un-changed since Buttonwillow, including the damaged stock limited slip differential which we unfortunately did not have time to replace.

The Good:

BC Racing ER Type Coilovers – Between Buttonwillow and Willow Springs I have now tested these coilovers on virtually every type of turn imaginable. Once I got the compression and rebound set to where I was happy, the coilovers continued to impress me. I absolutely loved being able to adjust the compression and rebound separately, especially since some of the turns on this track are very high speed and a little bumpy, so the last thing I want is a car that gets upset over bumps at 125mph mid-corner.

Nitto NT05 Tires – These tires are a large leap above the stock Bridgestones when it comes to grip! They were very predictable and surprisingly sticky for a stock tire. I ran the stock widths, with a little shorter sidewalls and it was a world of difference compared to the stockers. These are my new favorite street tire for the track.

GTSPEC Ladder Brace – This little piece actually made a noticeable difference! Turn-in felt more crisp and precise due to the lack of flex in the front end. I am sure it would be even more noticeable on a track with tighter transitions.

The Bad:

Hawk HP+ Brake Pads – These pads worked fine at Buttonwillow and on every braking zone at Willow Springs, except for one. The braking zone going into turn 1 you are coming down from around 140mph and it seemed that the pads couldn’t handle hard braking from those speeds for that amount of time. Initial bite was good, but then the pads would quickly fall off and felt like a sort of glazing effect. I knew it wouldn’t be long before the car was too much for a street/track pad, but surprised that the Hawk HP+ worked as well as they did. Time for some real track pads though now that the car is getting faster.

Broken OEM LSD – So this must have happened at Buttonwillow and I am not really 100% sure what part broke but as I was changing the diff oil before the even a large piece of broken something came out of the drain plug. The diff oil smelled extremely burnt as well. The car drove ok on the street, but on the track it felt like an open diff in spots. I am just happy that the diff didn’t self destruct and lock up the wheels on me. We will find out more about what happened to the OEM VLSD soon once I swap it out for a Carbonetic 1.5 way LSD. A diff cooler will also be added soon to protect it.

Power Steering Boil – Apparently an upgraded power steering oil cooler will be needed as well. After each session I noticed the power steering fluid literally boiling in the reservoir. The steering felt fine and consistent while on track but boiling fluid can’t be good. I am glad now that I am not running a wider tire up front. Larger power steering oil cooler will be added soon.

Fuel Starvation – This one upsets me more than any other issue. Turn #2 is a long banked sweeper that generates a lot of lateral load on the car and during practice I experienced fuel starvation coming out of this corner. The throttle would be cut and SRM would not work anymore. The car would coast for probably 10-15 seconds (or up until the top of the balcony for those familiar with the track) and then the throttle and SRM would come back and everything would be find. This happened with ¼ tank of gas in practice and then again in the second time attack session with a little less than ½ tank. This is the only turn it happened in, and it did not happen at all at Buttonwillow, but the high g-loads for that extended period of time did result in fuel starvation. Although at this point it would be fine at most tracks, as we develop the car into a better handling machine producing higher lateral g-forces this problem will become more and more of an issue. The easy and free solution is to run more fuel, but that is not an ideal situation with the added weight.

Mishimoto Oil Cooler – Unfortunately I have found the limit of the Mishimoto Oil Cooler kit this past weekend. With air temps in the low 90s and a track with A LOT of wide open throttle/high sustained rpms I knew that if the oil cooler could keep the oil temp in check under these conditions then it could last through anything. Unfortunately after about 2 ½ laps of driving as hard as I possibly could, the oil temp hit 270 degrees. Time for a bigger core. I still think that for the price this oil cooler kit is perfect for most everybody, with the exception of the hardcore track junky who will do track days in 90+ degree weather.

No negative camber up front – This was my biggest lap time killer this past weekend. All of my front suspension linkage is still stock so I could not get more than the -1.7 degrees camber gained from lowering the car. With the long fast sweepers at this track, the understeer was rampant and the outer edge of the tires were doing all of the work. The front tires were fast for about 1 ½ laps of hard driving before they would start falling off. Bear in mind this would happen to any tire without the proper camber settings. I will continue to try and wait for SPL Parts front camber arms, but if they are not going to be done before the next event I suppose I will have to go with the SPC arms.

Well our goal was to learn a lot about the car and that we did. Our quickest time of the weekend was a 1:37.286 which was good for 7th place in the Street RWD class, about 3.5 seconds off of finishing on the podium. Given the circumstances I am again very happy with the results and really think that the 370Z can be a competitive platform in the Street RWD class. Bear in mind that our 370Z fits well within the rules of the new Stock RWD class. If we had entered that class we would have won by 3 seconds. The Stock class is a new addition to the Redline Time Attack season which debuted at this Round #2 event. The reason we didn’t switch to Stock RWD is because we wanted to keep our Street RWD points from Round #1 and also I don’t want to have to worry about keeping within the Stock RWD class rules for the rest of the year. So despite a 7th place finish I am very excited about the potential of this car and this team down the road. If the car’s development keeps going the way it is, hopefully we can make a run at the Street RWD class title in 2010

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For those following the points chase, Round #2 marks the halfway point for the Western division Street Class. With two more events to go before a Street RWD West champion is decided, the DoubleDownMotorsports.com Project 370Z sits in a 3-way tie for 6th place in points, 37 points away from the leader.

Final Standings: Street RWD
1st - Jeremy Croiset - Berk Technology Toyota MR2 - 1:32.399
2nd - Robert Walker - Evasive Motorsports S2000 - 1:32.457
3rd - Robert Choo - DSport/Vortech/And1Performance S2000 - 1:33.739
4th - Charles Ng - Berk Technology S2000 - 1:33.850
5th - Jeff Tyler - Berk Technology BMW 135i - 1:34.241
6th - Manley Kao - TrackHQ/APR/Toyo Lotus Elise - 1:36.350
7th - Mike Bonanni - DoubleDownMotorsports.com 370Z - 1:37.286
8th - Rhys Millen - Hyundai/RedBull/Toyo/RMR Genesis Coupe - 1:37.392
9th - Kenny Chieu - Toyota MR2 - 1:37.385
10th - Jim Tway - Honda S2000 - 1:40.415
11th - Hiro Sumida - Toyota Cressida - 1:40.506
12th - Manuel Ortega - Bombsracing/Godspeed Project 240SX - 2:07.039

Here are some photos from the weekend courtesy of Berk Technology!

Here is a video as well. Sorry the position of the camera didn't capture much of any engine/exhaust sounds so I just put a song to it instead lol.

http://vimeo.com/4971642

travisjb · 06-02-2009, 08:06 PM

Congrats, and great write-up! A few thoughts/questions

- Power steering... do you think changing to higher boiling point fluid would help at all? can you re-use your old mishimoto oil cooler core as a bigger power steering core? Also, I added +1.0 caster recently... I suspect with the added caster and reduced airflow from oil cooler placement, I'm going to start having the same issue... troubling, power steering pumps are not cheap
- Brakes... do you think it would be different if you had ample ventilation? we're going to try and get some ducting going in my car with same setup to try it out... I had serious brake fade as well last time out, but I'm going to work the air flow first before doing more upgrades/ swapping parts
- GTSPEC brace... did you ship mine yet ?

- LSD... I'll post thoughts on the carbonetic after this weekend, if we can get the car ready
- Fuel starvation! it is finally clicking... I had this issue a while back (first track day thread) and thought it was just limp mode, but it didn't feel the same... I now realize I must have had both limp mode AND fuel starvation impacting that day... happened on banked turn at PIR... there must be several ways we can fix this... prob deserves its own thread for discussion, if there is not one already

M.Bonanni · 06-02-2009, 08:16 PM

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