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Posted by: consolidated Nov 15 2011, 10:34 PM

A group of us in Texas are starting a grassroots Spec 914 race series. It's a low key, low cost (yes, I lie to myself often) race series among friend-emies.

I race a Spec Boxster in PCA/NASA and also have two seasons of Chump/Lemons in our "hippie 908" 914-4, which was the inspiration/sickness for these new builds, but otherwise have little knowledge of 914's and asking for suggestions after doing much reading here.

What exhaust do you recommend? My car is a 75 914-4 1.8L ( all cars will be 1.7/1.8L) and I'm considering Triad and Bursch but unable to find much info on SSI or Thunderbird (recommended to me). This is a race only car so HP and weight trump noise/drone/durability/price. The spec requires stock headers/HE but otherwise free after the flange. We're using dual Webers.

Also, are wheel studs available, hoping to get rid of the lug bolts. Bullet nose even better.

Thanks!

Posted by: Borderline Nov 16 2011, 10:47 AM

Don't know about exhaust systems, but I just found this site the other day:

http://www.race-studs.com/servlet/StoreFront

they have different length and quality of studs to choose from.

Good luck with your spec racer 914!

Posted by: campbellcj Nov 19 2011, 04:29 PM

With carbs and a race application would you even want/need a muffler, versus megaphones?

Posted by: SirAndy Nov 21 2011, 12:50 PM

You need the back pressure, so *no* on the megaphones.

He said they need to keep the stock exchangers, which means the only place to do a crossover (to get the back-pressure) is in the muffler.

My choice would probably be a Triad muffler.
http://www.triadwestperformance.com/Products.htm

Posted by: DanT Nov 21 2011, 02:17 PM

my choice for that type of car would be either a Bursch or a partially gutted and twin piped stock banana muffler

Posted by: Brett W Nov 21 2011, 02:47 PM

You don't need backpressure. That is synonymous with restriction. Needing backpressure for an engine to operate is the biggest myth floating around the interwebs right now. Engines do no function well with backpressure. Any amount of backpressure will hurt cylinder scavenging.

Posted by: SirAndy Nov 21 2011, 03:20 PM

Interesting.

A well respected engine builder that frequents this board has said on numerous occasions that running an exhaust system without crossover on a T4 will net in loss of torque and HP.

His statements reflect my experience on the subject.

Posted by: Brett W Nov 21 2011, 09:15 PM

That still doesn't mean the engine needs backpressure to function properly. That means the engine is not properly tuned to use that type of exhaust.

Posted by: Racer Chris Nov 22 2011, 02:42 PM

totally with Brett. Backpressure usually results in part of the exhaust charge being left in the combustion chamber, which dilutes the incoming air/fuel mixture.
I think the term used was "collector", not crossover, but even that is a gross oversimplification and isn't necessarily true.
Pipe length plays as important a role as anything in exhaust design.
The problem with most 914 aftermarket "headers" is that they add length to already too-long primaries.
The problem with megaphones on a 914-4 is that the bad cylinder pairing hurts torque/hp.

Posted by: Woody Nov 22 2011, 05:29 PM

If this is the group that intends to run at Harris Hill Road then megaphones probably won't do. There are sound regs due to a pesky neighbor. I have an old Bursch that may fit and Consolidated, you are more than welcome to give it a try.

Posted by: consolidated Nov 23 2011, 10:28 AM

Thanks Woody, I may take you up on the offer. My donor unfortunately is more rust than car so we're looking for another.

Posted by: Woody Nov 23 2011, 12:52 PM

Have we met before? I'm the one running the silver 914 with the San Antonio PCA.

Posted by: consolidated Nov 23 2011, 03:18 PM

I'm not sure, I'm in Austin so we've likely met at H2R. I'm usually in this car with PCA and NASA...hard to miss.

Please come check out the series next year, it should be a lot of fun.

Posted by: consolidated Dec 2 2011, 03:54 PM

I decided to go with Triad, thanks all.

Posted by: RobW Dec 3 2011, 06:59 AM

Cool BoxSpec.

I like what you did with the headlights especially... nice when you see a mod that is better than factory...