Pomona / IDRC / NHRA 06/99

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Friday night at Pomona we had the photo shoot for Sport Compact Car. The feature article should be in the September issue, on sale in early August - hope you get a chance to see it.

Pomona notes: We considered this weekend as just a test session for us -- we did not think the car would be all that fast, and we were right.

There was a lot of "confusion?" (incorrect information) prior to the event about the sound limits the track was imposing. I had spent a fair amount of time talking directly to the track officials, and they were absolute on a 100db limit, no exceptions. From our road racing experiences with sound, we did not think 100db with any power left was possible.
Exhaust Tech constructed a HUGE stainless steel muffler for us to try. I routed the 3" exit pipe to dump under the car by the driveshaft. Our short test session (up and down the street a few times) was giving readings in the 100 - 104 range with a probable power loss - but this was their best initial shot, with no time to try other designs. Rather than pack it with very expensive "lathe shavings" material like we usually use, I went with the secret, high tech, porous, high surface area to volume ratio, high temperature material that has been used by some rotary road racers in the past (ok, I'll let the secret out --- $12 worth of barbecue lava rock from Home Depot). It really works quite well, just rattles a lot, which you can't hear in a race car anyway.

Anyway, on the Monday before the event, the IDRC website suddenly shows up with a "clarification" of the sound rules --- NO limit, just must have a turbo OR a muffler !! --- a BIG difference from 100db no exceptions. Since we only had two exhausts -- the muffler, or the straight pipes, we had no choice except go with the muffler.

For the weekend, we wanted to try the second stage of nitrous again (we changed the style and angle of the foggers), and the muffler. We also wanted to see what difference we would get at sea level, and to experience a weekend with cement bathrooms and running water, and WITHOUT 40 mph winds blowing cubic yards of dirt.

This weekend was also the first of the IDRC events "backed" by NHRA. Both spectator and race car turnout was less than impressive, but the organization/pairing looks like it has potential.

For Sunday, there were only four of us in the "Pro" class (and we were always the slowest - but then we were just testing). The other three were Abel with his R100, a 20B turbo MX3 from the east coast, and a 240Z with a 396 big block, 2 four's, with nitrous!.

Run-by-run is lower on this page.

Images (click on each for larger)

Other notes:

Nitrous: We tried system #2 at a previous Palmdale Friday night test. That time we tried launching with #2 at 25%, then added 25% of #1 about 1/2 second later. INSTANT intake backfire (about 10 feet from start line), engine dies, and track workers have to put out flaming air filter fire with extinguishers!! -- hark, something is not happy. Repaired the damage, TURNED OFF #2, and made a few more runs (see lower on this page).
Back at the shop, I took off the whole intake system, wired and plumbed so I could fire either system (gas and/or nitrous) to SEE what each solenoid and fogger was doing. I did not like the pattern of the #2 foggers - the spray was hitting the sides and the top of the small runners. We installed some older style NOS foggers that have a narrower pattern, and angled them down some more. The pattern looked much better, so that is what we tried in the first run at Pomona -- NO difference (backfired and burned another air filter).
Please remember we are new to nitrous, and are on a very steep learning curve. We now believe there is a fuel supply problem where whichever stage is turned on second, the fuel supply goes to a short, instantaneous pressure drop, which leaves nothing but nitrous to go into the engine. Result is WAY lean, instant explosion, with everything going back up the intake.
We will be doing some testing soon (running it up and down the street) to try and verify our conclusions. We will then re-plumb the nitrous fuel supply to give separate lines and regulators for each system. -- Still going to try sharing the nitrous fuel pump.
Also, since NOS believes we have now maxed out #1 (we are at 100%, about 210hp, with no problems) with the 3 foggers we are using, we will be adding ANOTHER 3 foggers to the big runners of the manifold. -- Hopefully it will start getting interesting then.

Licensing: A sort of back-asswards benefit to being slow at Pomona was there was no license problems (would not go under 10 seconds). We had taken the car to Palmdale for a Friday night license session. To "qualify" for the license you have to do 6 runs while they are watching. Run 1) half pass, Runs 2,3,4): "moderate runs", Runs 5 and 6): full passes under 10 seconds. There was only time for the first four runs, so sometime this summer we need to do the other two runs -- but not until the car goes consistently under 10's.

Next sure outing is October at Palmdale, but if we get things working better soon enough, we might go to Sacramento in August. The most current problem is how far behind (in everything) the drag car has put the normal business of Mazdatrix. So first priority is to catch up, clean up, put away, organize, and generally get back to normal business operations. We have a lot of new products and projects that have pretty much been on the "back burner" for a few months while we did the car testing and two weekend outings.