To add to what seems like everyones else opinion on here, yes I have found the information on Vtg upgrades available somewhat vague in some cases, not all.

TTdude, you seem to really know your stuff. I have a Proto 100 oct tune and am considering the 63.5mm vtgs. Noticeable power difference w 65's & 100oct over 63.5 you think? Any pros or cons you can share w us? Im sure it been discussed before, but since we are on the exact topic, just looking to further elaborate...

Thanks guys

 

When I did my vtg upgrade only 63.5 was available. Now I don't think there is much difference in price? If not, I would go with 65 mm w/ clipped turbine. The 63.5s are very nice turbos--very responsive-- and will give you sub 7s 60-130s.

 

What are your thoughts on the CMS 68mm setup?

 

I have ttdude's 63.5 vtg turbos (thanks Dave!) on my car - they have the clipped hotside but not the extrude. When I was asking Todd about getting 65 with extrude he didn't think it was worthwhile for me since I would be using pump gas. He said the lag difference would be noticeable unless using racegas/E85/methanol. Just send him an email and see what he thinks these days, who knows there may be some new developments that would change his mind.

 

I've seen datalogs of those turbos on a 997. CMS uses their own datalogger and it reads/calculates Load differently than a Durametric but that turbo pushed over 2100 MAF units compared to my set-up which produced around 1650. It was impressive but you have to contact Tom at CMS for the specifics about what other supporting mods are needed.

Hope you still like them. Are you doing/planning any upgrades over the winter?

 

And in some cases sub 6s 60-130 ;-)

 

5.88 to be exact.

 

Correct, i just got bored wating for another VTG car to come close ;-) Please don't mention Kercar's car who made this onece on 1,9b boost ;-)

 

You made some huge gains! Did you ever post what's in the secret sauce?

 

Sure, i have posted all modds done on my car, extruded hot sides, y pipe and lightweight wheels made the difference

 

I've said it a million times milou....we do not test our kits for 60-130 times, period. Where we are located it's simply not safe to do and we will not put any of our own cars or customers cars in danger just to get bragging rights on the forum. We took our own 997 Turbo with the 68mm kit to the track, and ran a best time of 10.2...but kept breaking axels during the launch, so we gave up. I have a customer who runs his 68mm VTG kit in the low 10's, but chooses not to post on 6Speed. He's here...he reads the information, but chooses not to get involved.

We've shown proven HP figures time and time again. What more evidence do you want? We tune for HORSEPOWER. I have gladly published more data then I probably should have showing evidence of how much ACTUAL power our turbos produce to the wheels. From that information you can deduce the performance figures.

And sure, KerCar only did a few runs, but they were legitimate, they were documented, and they still stand as the VTG record.

 

Tom, did you get an answer from your tech guys about beckpressure?

 

Hi Pete....yes I did ask. We have measured back-pressure on the turbochargers only a couple of times...but each time was at higher boost on cars with built engines.

However, the info is still pretty valid. At 30psi boost, we measured 60psi back-pressure in the manifolds. At 25psi boost, we measured about 48psi back-pressure in the manifolds. We only did these measurements a few times for a few particular cars as we were testing to see what type of turbine wheel modifications were necessary to get max power. Hope the info helps.

 

The guy that bought KerCar's 68 turbo kit (he beat me out by 1 minute) has done the 1/4 in low 10s at 135mph, and says 60-130 was high 5s on E85...

Wow Milou, didn't realize you were sub 6 for 60-130. Talk about squeezing everything out of the 63s!

Since I'm going to be using pump gas (94 octane up here) I'm not even close to 6s. That's why I'm hoping to see some pump results for the 68s before handing over the dough! And I will hand over the dough if the times show a decent improvement over my 7.2s on pump gas.

 

Hi,

Since your wp is down do you have any dyno's to share on your 65&68mm upgrades with a stock baseline?