Tom W

I had the shop take my Turtle in to have it dyno'd prior to doing some "enhancements" and was surprised at the result: 244 rwhp. I expected about 220. It will be intersting to see if it has an aftermarket chip in it already (it's not supposed to have one). FWIW, I have not seen the plots (I got a call at home last night to get informed of the results) but I'm told the car is running really lean above 5k and hp drops significantly above 5k too. I'll post the results once I have them in hand and post the "after" results too. My car currently has a cat bypass and a secondary bypass but the stock primary muffler and a "cup" airbox (ie, no lid). I use 100 octane gas.

I'm having an RS LWF/clutch added and a new chip and exhaust (headers without heat exchangers and exhaust that will meet the 92 db requirements at Laguna Seca). As the Turtle is track only, I can be a bit more aggressive than those of you with dual purpose cars. I'm looking for a minimum 20 hp improvement.

So, the point of all this - based on a search, I think Joey and a few others have done dyno runs with cars similar to mine currently and only seen about 220 rwhp. Who else has done a dyno run? What did you see with what sort of setup?

bhensarl

Wow, 244! What's the conversion factor for bhp from rwhp? Isn't it something like you lose 15% through the tranny? Any idea how much hp you get from the cat bypass? If I remember correctly the gains from the secondary bypass are fairly negligible, right? I'll be interested to see what results others got on the dyno.
Brian

tonytaylor

My last dyno run ( in the archives here ) gave 250rwhp/298@flywheel. IIRC setup at the time was stock airbox with "performance" filter, MAF, cat bypass and custom chip.
244rwhp is , IMHO, attainable with your setup,if chipped to suit but does seem a bit on the "healthy" side. How does it run against other 964s in a straight line?

Tom W

Tony: I have not run against another 964 since doing the cat bypass and a few other minor tweeks, but is was pretty even against an RSA. The other 964 drivers I see at the track are more experienced so it's hard to distinguish car from driver. That's partly why I wanted the dyno data as it removes the driver from the picture.

tonytaylor

I understand what you mean by different levels of driver skill influencing lap times which is why I mentioned on the straights. Often when running behind a car on the straights it becomes clear you have more or less power than a similar car.IMHO it's the best indicator of relative (straight line) car performance.
The problem with dynos is that they only give a snap shot of engine performance and unless cars are measured on the same dyno in the same conditions then the numbers are not comparable.
I have been on track with Euro RSs,at the time 100kg+ lighter than my C2, that were supposed to have 300bhp and been able to drive past them on the straights. As a result I'm a bit sceptical over some dyno figures. It isn't that the figures are deliberatly false just that comparisons with different dyno figures can be misleading.

forklift

I really hope to get my dyno'd soon. Someday.......someday I will post my track videos, but at the long straights at Summit Point and VIR I keep up w/ Corvette Z06s very well. They pull me, but only slightly. They are on it also. My car seems to really shine between 90-140, maybe the primary by-pass....or probably my imagination.

There was a post not too long ago here or on the 993 board about variances w/ dynos...and they were huge.

Tom W

Tony - I understand completely, I just worry about corner exit speed influencing the results. In the end it's track performance that matters to me so your measure is likely the best. I just hate it when those pesky 993tt's walk away from me on the straights and I, like a 914, catch up in the turns. My goal is to be able to hold against a 993 and stay close to a 996 and I think I need a few more hp to do that based on the last year's track events.

tonytaylor

I guess you can never have too much hp

The scenario of having a high hp car pulling away on the straights only to catch up on the corners is frustrating. Once you've done the basic performance upgrades extra hp becomes very expensive and there are always other areas to spend money that in all probability give better value for money. Pulling weight gives a better bang per buck at the track.

All IMHO

racergreg

I agree with Tony completely. I bet you could easily and inexpensively remove 100 pounds or more from your car. This is especially true if yours is a dedicated track car, and you are not too concerned with creature comforts and eye candy.

Remember that less weight will also improve braking and handling!

Dr Strangelove

For what it is worth, my Carrera Cup car dyno'd at about 239 rwhp. Supposed to have a little more HP than stock and, of course, less stuff hanging off the engine.

Tom W

Weight reduction is nice, except the silly racing organizations have rules about what the car must weigh and what may or may not be removed for a "prepared" class car. I've already removed what I can and probably too much, the new corner weights will let me know. I'm aiming at E-prepared in PCA terms or K-prepared for POC. Given that weight is restricted, but I am allowed any exhaust I want and can change the chip, that's what I'm looking to do to squeeze as much as I can out of the engine I have (for a reasonable amount of money). I have no desire to get into the classes where the size of your wallet plays a much, much bigger role in the car's performance. I'm busy trying to work on improving the driver, it's cheaper.

Dunasso

Tom,

Sounds like you got it figured out. Once you go digging deep, then your trying to hang with bigger wallets and that is a difficult transision. I've raced in different classes when it came to shifter-karts and dirtbikes, only to find myself back where I started. If I ever get the chance to start racing Porsches then I'll be following your strategy. The more you drive the faster you will become, and the more tricks you'll learn along the way, and Tony makes a good point of showing how true it really is.

Duncan

garrett376

So Tom, will I see you at the track sometime soon??? You can see how bad you pull me on the straights in my 4wd beast!! I want to see how much the 4wd transmission loss makes a difference.

Hopefully I'll see you at a POC race sometime - CA Festival of Speed perhaps?...

chris walrod

Tom, while riding in your car at BW, remember me commenting about how well your car seem to 'pull'? I thought it ran great, better than the RSA that I maintain for a good friend!

Tom W

Chris: I've always thought it pulled pretty good. I only have a 993 with a LWF and short gears to compare it to, so it doesn't "win" (yet).

Garrett: I hope so. POC says they will accept my experience and GGR/PCA time trial certificate to start doing time trials. I plan to do the final NASA bits over the next month or two and get my provisional license with them by summer and do a PRC race. I don't think my work and skiing schedule allows a POC event until April or May.

Duncan: I hope I realize what I'm getting into. I was 2.5x my "budget" last year due to many unexpected repairs to the car. I hope to control myself better this year and limit spending.. I say as I'm planning to dump a few more bucks into a totally optional LWF and headers/exhaust and chip. I can only imagine how bad it would be if I didn't stay in a "lower" class car.