Oh ok, we'll I'm going to be on stock internals as well and I'm 6 speed. I would still be interested in a friendly race. I'm mainly looking to see how I perform against big build gtr's at the event, but if we have time I would love to get a race in against the 68mm vtg car.

 

Definitely, would be great to meet up with you there. We'll be in contact before the event!

 

As far as vtg's getting hot and backing down a little, no I do not have a vtg car. I did ask plenty of members and tuners and they did tell me after a couple runs in the heat, vtg's will not perform as strong as they did in the first pull where gt's will keep pulling strong. Now thats coming from people that owned the kit or companies that offer the kit. Your the only company that has said otherwise.

I never said anything negative about you or your company. The only thing I have said is that for 30k for a vtg kit I rather go with a gt30 or alpha kit. That's not saying anything bad just an opinion and this is a forum.

Also as far as the dyno vid: We all know that dyno #'s don't mean anything it's how the car performs.

On the 5.5 car wasn't there some controversy? Didn't he say that he was running at a higher boost level than you guys said you tuned him for. Out of all the vtg kits you have done over the years that's the only person that posted a time like that, nobody else posted. Just seems odd honestly.

 

Couple of quick items.

One, I plan to build the internals as well as I realize the stock internals are only good for ~600-650whp or so based upon my reading.

Two, I plan to add a cage and race harness along with a HANS device, I will not however be putting in the door rails as this is my daily.

Honestly, from everything I have read, the comparison between GT's and VTG's is an ongoing one with both sides adamant their setup is the better. I must be honest, I am in the middle and not sure which direction to move in. I am familiar with Garrett turbos coming from my GTR34 and EVO IX. My GTR was a built car with an RB30 hybrid engine build and did about 725whp, however I must admit, that was when I was doing street racing/drag racing and not road racing.

After some thinking/additional research, it may indeed make sense to lower my power goals as this is a road racing car and not a drag car and turbo lag and overheating is a big concern of mine in this field. As I mentioned above, I dont mind spending the money to build the internals, however I dont want to compromise turbo response and performance for power, especially as road racing does not require the same massive amounts as street or drag racing does.

Luckily, I am not one of those hard headed guys who are closed to suggestions and HAVE to do things MY way, hence the reason I posted this thread to get other peoples suggestions and input. I myself am relatively new to the Porsche world coming from JPN Imports primarily and I am here to get input and learn. Please feel free to make any suggestions and know I will not take it personally.

With that said, since it sounds like most dont recommend this amount of power for road racing, what would be the recommended amount of power and setup? Sounds like stock internals will suffice since we are lowering the power to road racing specific targets?

Thanks for the input!

-Sayajin

 

Keeping the car cool on the track is the key, so you want most efficient and coolest compressor on the intake side for your power level (i.e. 18psi with bigger compressors is probably better than 22psi with smaller compressors); while using larger a/r turbine housing and efficient turbine wheels to get the exhaust out as efficiently as possible.

Give your hp goals, you are better off using a set of custom proven turbos for your needs. Nothing against modded VTG turbos (I have them on my car), but if I was prepping my car for track duty, I'd ditch them. They are just more complex, with more moving mechanical and electronic parts, thus more likely to fail under repeated track use and heat cycles.

 

As my car has been brought up as a point of reference in this discussion - I think it's pertinent to point out that after talking to Proto and reviewing logs from my 60-130 and other runs, that I found I had a massive boost leak. I had apparently popped the vac line off of the fuel pressure regulator, causing my car to both run super lean as well as not make the boost nor flow the fuel we were asking for. So... the results I achieved (6.9, in 105* heat, on a 2.5% incline, with a 300lb passenger) need to be thrown out. I'm out of town for a few weeks, but when I get back I'll be re-doing my runs late at night when its cool, by myself, with the boost leak now fixed. I fully expect that we'll be looking a a completely different time, much closer to the 5's.

Re: Champion's 5.55 time and questions re: my car.
1) It has 67mm VTGs Tom, Todd has just started making these new turbos. Much more comparable to your 68's, though without the billet housing. I fully expect the champion 68's to flow more, but not as much more as the older 65's. I simply chose to work with proto as he's near to me etc etc.

While I dont know what whp Champion's (Kercar's) car was making on it's run, and Emre seems to say the logs showed it was making much over 22psi at the time, I would believe on a good run with the right situation a 5.55 *should* be possible. Hell, it happened, thats a fact. The only questions are what boost/whp it was making at the time. Who cares, it ran a 5.55 on VTG's and nobody argues that.

So... back on subject. I think for a track car, a VTG car properly set up would be more than enough car. 800whp means built motor. If it was me, either A28s or 67/68mm VTGs on race fuel (e85 or MS109) would be my choice. Pump gas has too much variation for my tastes.

 

Honestly a Switzer P800 kit would be perfect for what you want. Just have them make you different maps for what you want.

 

+1 Agreed

 

I honestly feel your Proto build is the strongest VTG Build out there with the E85 and the 67mm VTG's together. Thats why I used you as a referance. I think your car is the only E85 VTG car that Todd has actually had in shop with the larger VTG's so he can dyno tune it himself right there. So im sure it is tuned perfectly. I really feel in the right circumstances you can hit high 5's. Like I told Tom I believe there was controversy with Kercar's car and Nobody else has ever reported a 60-130 time even close to Kercar with a kit from Champion. Looking forward to your new times. Best of Luck

 

The "controversy" with KerCar's car was that he and Emre claimed that it spiked at higher then 22psi of boost for a moment during that run and then settled at 22. His was car was not tuned for 22, meaning the ECU never requests more then 22 psi. How they saw more then that is a mystery to me. It could be because they use REALLY bad pump gas which is equivalent to about 90 octane, and then mix it with some fuel additives. But...22psi or not...he did the run, and he did it on VTG's. No arguing that.

67mm exducers on the compressor wheel? Hmmm..that's interesting. As I've admitted many times before, our turbos were designed in a partnership with Tial. During our testing, Tial found there was a total lack of efficiency when trying to use anything larger then a 65mm exducer in the factory compressor housing. This is Tial who came to that conclusion...and they know turbochargers better then anyone! In fact, it's Tial that makes the upgraded VTG's for most tuners. I'd be curious to know how someone got a 67mm wheel in there, and made it efficient!

 

Yes sir, 67mm. I couldn't tell you the technical side of the how, but I know blouch is who does the work. It flows quite well, I know Todd said its the highest HP he's seen on VTGs in his shop. I know he's done 65 and 63.5s in there before, and he's tuned your 68's, but IDK if he ever had any physically on his dyno before. It is quite quick when I dont have a boost leak, which is why I'm less inclined so say the 5.55 never happened :-)

Overall though, this is a stepping stone to alphas for me. Todd built me a full alpha kit, and the only change i need is the turbos. All other parts are on the car with the vtgs.

 

Tom (or any expert pls chime in as needed, real question from a rookie and I do like to see both sides of the arguments):

I do not understand the criticism here. If the car is fast and safe, why should it even matter that boost pressure went higher than 22? To me (my humble opinions, etc.), the 4 primary parameters of a tune, in order of importance:
1. Engine doesn't blow up
2. Smoothness
3. Vbox times, track times, etc.
4. Shapes of dyno curves

Obviously there are numerous other evaluative parameters, but essentially, if the above 4 meet requirement, why does it matter that the boost has to be a certain level? What's so magical about staying under 22?
Looking at it from another perspective, in other words, if the car is fast, safe, and makes a great time, why should I care what timing angle, boost curve, afr, etc., are one number, versus another (within reasons of course)? A time slip doesn't become invalidated because for example, AFR doesn't look good, no?

 

The reason is b/c champion and todd don't run over 22psi on big VTGs due to the tq they make. Higher boost assuming you're running efficiently will mean more power and more torque, beyond what the stock rods will handle. My car runs 21-22psi flat, as do champion's big vtg cars on a stock block. Once you have a built block you crank it up to 28psi and make much more power. See champion's 840whp vtg car as an example.

So you're point #1 of engine doesn't blow up will not be true when you push beyond 22psi or so. So the 'controversy' was that Kercar's car was running a claimed 28psi which would mean the engine would not last very long before it broke. Tom says it was not running that boost. But the end result is, it DID run a verified 5.55

 

The angle that I was looking at is that champion sells this kit and states it has gone into the 5's. Champion only tunes to 22psi though and this car ran it at 28psi which means everyone that buys it will not come close to a 5.5 60-130 because they will be running a lot less boost. That's why nobody else over the years has come forward with a similar time. We know champion has sold plenty of kits. Also isn't there a good chance somebody else tuned the car to push it the extra 6 psi more? Yes they were champions vtg's but something with tuning doesn't add up. If he was tuned to 22 how did it reach 28 and the results of this kit are advertised as it hitting a 5.5 but a normal customer will not hit that at 22psi. You get me now can? Not here to talk bad about champion just answering your question.

 

Well...that's mostly correct. The reason most people don't tune VTG's over 22 psi is because the ECU can't read over 2550mb. There are limitations in some of the factory hardware that won't allow you to tune over that level of boost thru the factory ECU. Unless you know a few tricks and have GIAC on your side.

That being said, we stopped at around 22psi, mainly we feel that's a comfortable power level with our 68's in order to not grenade the engine lol. Above that, bad things start happening to rods.

Just to clarify....they said they saw a spike of 27 or 28 psi...but only one time and not necessarily in the run that got the 5.50. KerCar ran the 5.50 several times, and 5.6 a few times, etc. It was very consistent....we only submitted the best run for listing in the ranking.