Been a while since I've had the time to update the progress on this lady. But I feel like I've finally caught up to being some what prepared for our races and the car has done very well.
I've been transitioning from the LeMons circuit to a new group called AER (
http://www.americanenduranceracing.com/) . Basically, it is like LeMons, but without the LeMons dog and pony show. No themes, no BS judging and they actually let you race without being penalized. This also allows a slightly higher level of modification as there is no $500 limit (which most A-class LeMons cars have surpassed eons ago anyway). The level of competition is high and the cars are very fast, but still within the reach of the average team budget. Many Spec E36/E46 cars , the fastest putting close to 300whp down. Overall though a mix of lots of different kinds of cars from all over.
So back to the car. As we were being more sucessful and spending more time out on the track. The current setups short-comings were becoming more apparent. Really we have had almost no mechanical failures, but transmission used tranny synchros were wearing out, our little TE05 turbo was weazing and I was worried about high EGTs and high inlet air temps causing some sort of catastrophic failure. At our inagural run with AER we lost some coolant due to a faulty expansion tank cap and the car was running hotter than normal. It had been some time since its last head gasket so I thought it could use a refresh as well.
First the transmission was changed to the S&R 4-speed. At the same time we decided that it needed a proper shifter as well. The 4-speed went together with a little resistance (mostly just me trying to source the right parts), but it seemed to come out just fine.
For the shifter, we based the the geometry off of the Luke's 9sport unit that we love so much and machined our own version. The car shifted great after a short break-in period, but we felt that not having a reverse lockout was making the 4-3 downshift difficult at speed. We redesigned the base plate to accept a lockout pin and gate system. Once the bugs were worked out of that, the transmission shifted effortlessly (as long as you double clutch!)
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To tackle the EGTs and inlet temps a front-mount IC and better flowing turbocharger would do the trick. I purhased the largest front mount unit I thought would fit and some universal piping.
http://www.eeuroparts.com/Parts/76438/I ... DO88IC190/I thought the end result came out very good. I used two 180* bend 2.5" pipes modified slightly along with a factory pipe and a 90 reducer coupler off of the turbo. I tried to keep the parts somewhat protected and off of the ground. Not having to have headlights made this much easier.
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For the turbocharger, I really wanted to go the disco potato route, but felt it was a little over the budget. Instead I went with an rebuilt Volvo turbo. A TD04HL-16T with the straight 2.5" housing. Being able to bolt up to the SAAB exhaust header at least took one issue I didn't really have to worry about. There were still plenty of other issues including the clocking of the center, inlet and exhaust housings as well as fitting the wastegate after doing so. Not to mention all of the oil and water plumbing.
I came up with this:
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I moved only the exhaust housing which made it difficult to fit the wastegate, but made the IC piping very easy and relatively close to stock orientation. We actually had a fairly good 3" downpipe that had been modified a few times, but it was always choked down to bolt up to the small tiny turbo. I made an adapter flange that took the 2.5" to 3" v-band to make exhaust removal easy and loose nuts a thing of the past. The Volvo flange is something we made up and should have available at some point in the future for those who want to use these turbos.
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Next the head. The obvious choice for me was to use a 2.1 head for its larger port sizing but also not having to create a custom intake and ancillaries for the T5 head was very appealing. I also had a few on the shelf. After a pulled the old head off, I did notice the gasket starting to go as well as some custom valve reliefs that the exhaust valves had left on every single piston. I wasn't sure if this was due to valve float under the 7000rpm limit of if someone had a bad mis-shift and over-reved the engine. None of the valves were actually bent and the bottom end had been good to us so far, so I just smoothed out the sharp edges in the pistons and moved on. After investigating the valves differences between the c900 and NG900 heads a while back I noticed that the T5 intake valves had a nice relief around the let ports yet still maintained the same stem thickness. They are also a few grams lighter than the standard intake valves. I thought this would be a good match for our head. Being 1mm oversized while the head was out being cleaned and surfaced , the new valve seats were cut. The Volvo 8v springs were used as well to increase the spring rate and keep the exhaust valves from floating at high RPMs.
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