My GTR at Willow Springs International Raceway *VIDEO*

[San Diego GTR]

My son and I just finished the Ultima GTR and this was our first track event with it. I had some fuel problems that can be seen in Steven#2 video with vapor lock. Not the cars fault, but mine in the design. I had added an aluminum skin under the front of the motor which allowed temps to get way too high in already hot conditions (106º). I removed the skin and wrapped some of the fuel lines with aluminum heat shielding tape, but by then the weekend was pretty much over. The car ran great in the mornings but by lunch time, the heat soaked into the tanks (My tanks are bare aluminum), heating the fuel and things were pretty much over for us. The Paul video and the Steven #1 video were both in the morning of our first day. The other big problem we had was the cable shifter for the G50/52. CMS has a very nice side shifter, but they use a small set screw to hold the rotational arm on the shaft and that is inadequate in my opinion. It was slipping making every shift a surprise as to what gear we were going to get. Since I've returned home, I've replaced the set screw with a SS bolt through the whole shaft and I love it now. It is very positive with great feedback and feel.

I have to say, this car is way more capable than you see in these videos. We are not professional drivers (as you'll see) and we aren't pushing the car anywhere near its limits. This was our first time out and we wanted to gain confidence in the brake set up, the cars handling and the LS7 power. The LS7 is an amazing motor! You really have to be careful exiting the turns or you'll easily break the tires loose. I never had that much power in my Cobra replica.

Anyway enough of my chatter... I promised videos.


http://gallery.mac.com/quailpark#gallery


Paul

[ROWDYRENAULT]

Paul First of all a general word about Willow. When Paul says 106 thats the air temp not the track temp. Willow is very fast with lots of fine sand right next to the track. Plus crosswinds of 20 plus miles per hour through 8 and 9 the fastest turns on the track are very common. Big Willow as its called in deference to The Streets of Willow a much more forgiving track is not for the faint of heart. If you can get any car to cool correctly and not vapor lock at Willow most other tracks will be cake. If you can get 90% of what the GTR is capable of out of it at Willow you may not be a pro but your absoultley a very talented driver.
The CMS cable shifter which I also have has some faults one of which you have found. The supplied set screw with FINE THREADS into aluminum is not a great idea. Add to it that the set srew is to small and your problem was going to happen. I know, I did the exact same thing. I have changed to a thicker arm so that we have more depth to leverage against the shaft and gone to a bigger set screw with course threads. The next step will be to replace the Aluminum arm with a steel arm if I have any further problems. THE ANSWER IS FOR CMS TO STEP UP. the shaft should have a flat on it or splines one or the other the set screw should not be seeing the twisting load only holding the shaft in place. The second place that could use some help is to go to a better selector up front. I have had a piece from Jim Cunningham 2602 437 3107 that with a little bit of change on how the cables mount to the box would work better and it is reasonably priced. This is not a trash on CMS I think the cable shift has great potentail it just needs a little more work Lee

[LuckyP]

Agghh! I'm having probs trying to run these vids.

[San Diego GTR]

Lee, I can't really point blame at CMS for this as we all have our shift arms mounted in slightly different places and they can't predict where the flat spot would need to be placed. I'm fine with the bolt solution.

Lucky, Do you have Quicktime installed? They are large files so they take a while to download.

Are there any secrets to the CV joints not spraying grease all over the engine compartment?

Paul

[k wright]

I have twisted my set screw around the shaft and when it is placed in the final location it will get pinned. I think that the set screw should be viewed as a temporary measure.

Glad to here that the shifting was cured with this system. It is the only viable option for a left hand drive car with dry sump and twin fuel tanks.

ken

[crafty]

Are you running a swirl pot? If so, and you return fuel to the swirl pot (rather to the tank) this could be contributing to the vapor lock problem as warm fuel returns to the swirl pot.

[San Diego GTR]

Crafty-I don't know if we're using the same terms or not, but my fuel system comes from each tank to t 'T' and then through a filter and the pump. It then goes to the regulator which has a gauge I've set to 60 lbs and has one hose to the fuel rails and one directly back into the tanks. After removing the aluminum skin and wrapping the fuel lines that are exposed to heat, it runs much better. My air intake is costing me lots of HP I'm sure. Not only is the K&N filter too small, but it draws from the engine compartment which is about 125º at idle.
Paul

[crafty]

I was talking about a fuel swirl pot - fuel pumped with a low pressure pump into a swirl pot, the high pressure pump feeds from there to the engine...you dont seem to have one.

For cold air intake on an LS engine - check out how Jeff did it before the Twin Turbos....


He made an airbox around the filter with a rubber seal on top.





Then he bonded a panel inside the rear clip... closing off the scoop to make a plenum that directs air to the box. You can insulate the box and the plenum...

Edited by crafty on Monday 21st July 06:56

[ROWDYRENAULT]

Paul: I appreciate that you come from the point of "if you can't say anything nice do'nt say anything at all". CMS charges substancail money for this product. Set screws with fine threads in alloy is mistake one. no index on the shaft of some sort is two. I will bet you a dinner that unless you modify CMSs setup that you will see this problem again. My point in this is to raise awarness in potentail buyers of this system, that it works, I think it has addvantages over the rod setup from the factory, but the only way that the problems listed above will be resolved is for CMS to correct them. I had a conversation with them, they didn't sound like they felt they needed to adresss my concerns, so I did it myself. Also for those of you buying this system make sure you get a set of instructions. last thought all of us are motor heads we have all dealt with these kind of problems before, if we don't share info and pressure manufacturs through thier market place we can all just keep fixing problems that should have never occuired. Lee

[DavidSalama]

FYI,

I had the exact same problem with the CMS shifter arm. Started missing shifts at the first track event. My engine builder machined a more secure steel insert on an aluminum arm. It been perfect since then.

I am guilty of not giving feedback to Renegade Hybrids from whom I purchased the kit.