Aux. Port setups for Racing...
 

Okay... I've burned hours at work (yee haw) studying the findings of searches in the 2nd gen forum but none quite answered my situation. It is as follows:

2nd Gen
N/A S4 w/ some porting...
S5 UIM & LIM or combination thereof...
ACT Exact Pro Lite Flywheel...
Racing Beat road race header...
No Rules in my series pertaining to this so I'm free...

I'm coming from the world of Turbo to N/A so what should I do with my aux. ports and that VIM thing?

Disable? Remove completely? Pineapple? New acctuation system? S4 LIM and S5 UIM? Wire them open?

What are fellow racers opinions/experience with the available options? I will be adding power wherever possible over the seasons to come, and port further, and the car probably weighs in at 2500 lbs.

The SCCA lets us leave the aux sleeves stock or remove them all together. Mine are removed. The motor never sees a situation where they would close anyway so why have the restriction? Supposedly the Pineapple sleeves flow better than no sleeve. If the rules allowed I would do one of two thing. Use the Pineapple sleeves with the actuation pin removed from the sleeve. Use some method to make sure they stay in the open position at all times. Or (and I've experimented with this but never finished the motor) use Devcon to fill the aux port and reshape the tract for a nice smooth entry in to the aux port. I think this would ultimately be the best setup for circuit racing if you have to use the 6-port irons.

As far as the VIM. Wire it in the high RPM position. Once again, you will not see low enough RPM to use the low RPM range. Wire it and leave one less thing to malfunction.

I rebuilt my 6-port with the devcon transition in the auxilary and a mild street port elsewhere. It is lacking in low end power but it always did that. This engine is safe to 8500rpm. I'm currently installing a fuel computer and will soon have some dyno runs to see the results. Unfortunately I will not have any base runs as the car has issues with the factory sensors, wiring harness and such. I'm hoping for 170-180 at the rear tires when all is said and done with the tuning.

Once upon a time, under the guidance of Rob Golden at Pineapple Racing, I used a rod of Teflon. Turned it down to create a tight, interference fit, rammed it in place, then shaped it into a nice bowl with a die grinder. Worked great. This was a very agressively street ported engine, but no reason it wouldn't work on a stock-port motor.

http://rx-sevenandahalf.com/misc/por...flonshaped.jpg

That sounded like a great idea until I saw McMaster-Carr wants $60/ft for the stuff.

Did you guys do any before and after flow bench readings?

Flow benches are pointless in evaluating rotary engine ports due to the turbulance of port opening and closing, which connot be duplicated faithfully. The best way to evaluate gains are on a dyno or – even better – at the track.

I never did a before-and-after with that car, since it was a throw-together project for the Grassroots Motorsports Challenge and too much changed to attribute gains to any one thing. But I did do a 14.7 quarter mile ET with the thing falling on its face at the 1/8th mile mark (non-GSL-SE 1st gen fuel pickup and stock GSL-SE pump...D'oh!) and it had enough grunt to snap the tranny output shaft a few runs later (someone else driving, bogged the launch). Regardless, that was one strong performer, in my opinion. I attribute the gains to the "system"...both traditional porting and the Teflon inserts. Here are some more shots of the porting:

Primary Before: http://rx-sevenandahalf.com/misc/porting/stock-pri.jpg
Primary After: http://rx-sevenandahalf.com/misc/porting/streeport1.jpg
Secondary-side Before: http://rx-sevenandahalf.com/misc/por...PIwhousing.jpg
Secondary-side After: http://rx-sevenandahalf.com/misc/por...-ported6PI.jpg
And, of course, with the Teflon: http://rx-sevenandahalf.com/misc/por...flonshaped.jpg

The Pineapple Racing 6-port sleeve inserts are estimated at 6-8 hp gain, based on 1/4 mile trap speed improvements and 2nd-hand dyno confirmation. Logic tells me the gains from removing the sleeves entirely and properly contouring the ends of the auxiliary port runners is certainly greater.

I much prefer Teflon to the throught of using an epoxy for the job, simply because epoxy can be lethally ingested should it crack and come loose. I know Devcon and the like is sucessfully used in blocking ports (as with a PP) and such, but I am wary of the use in this application, where in places it is spread very thin and there is no mechanical "keying" (as far as I am aware). Probably works fine 99% of the time, but with my luck I am always in that last 1%. Teflon shreds and compresses well and, while I wouldn't volunteer for the experiement, probably non-lethal if ingested...or at least minimally damaging.

I know Rob is considering having some radius inserts CNC'd for use without the sleeves, but I don't know if they will ever be made available to the public due to the necessity of mechanically fastening them to the housing. Particularly worrying due to what happened when a few customers failed to follow directions on installing the inserts in the auxiliary sleeves.

A buddy used devcon to build up the hole and smooth the transition in a 13B street port. With 90 rotors and a weber carb the thing pulls like a beast all the way up to 9500.

-Trent

Is that Karls car?

And Trent, are you blinde? Cause i've had that front lip on my car for a long time! haha....:p:

You could replace the Teflon with Delrin if you want to go real cheap.

You just described my engine but I'm starting with the factory intake and an aftermarket fuel computer. We are working on an intake manifold to utilize some motorcycle throttle bodies(quads) that might find their way onto my car.

he he

Its funny this thread is here.. I JUST got done grinding all the Devcon Plastic steel Putty out of my 6-ports because I didnt take the time to check if adding to the ports was legal in EP :doh:
They were Realllll Nice. Very strong material.. bit spensive at 33 dollars for a 1 pound container.. specially after grinding some of it onto the floor.

BUT it was real nice looking. Forgot to get a Pic of it.. but have Pics of the intake porting without the Devcon. Will throw them on my site for one of these porting posts before the weekend.

Yes, The ports I'm talking about are in Karl's low 13 second wagon. The ports were just beautiful when he finished porting them.

-Trent