I should really say "second impressions" because the first impression went something like this: step on gas, hear a lot of whooshing without any acceleration, step off gas. Lucky for me that I recognized this as a boost leak and limped home. The tech working on my car forgot to tighten the ypipe clamp.


Second impression a whole lot better - I ran it with the tune from my Proto 63 vtgs (I was told that would be okay). Other changes include larger turbo inlet pipes (thanks to Prodigy), new spark plugs, 5 bar fpr. It felt stronger in the 4k and up powerband but the pbox said it was the same, lol. Less than 4k was a little weak, but that wasn't a 68-specific tune.


I waited and waited for Proto to take a look at my datalogs and make a custom map for me but I guess he is just too busy. I reached out to GIAC to see about a trial tune but I never heard back from them right away (they missed my PM) and I was getting antsy after spending $$$ on the turbos and not getting anywhere so I looked at other options.
Champion offered to give me a money-back guarantee if I didn't like their GIAC tune. I'm sure I would have liked it but it meant sending the ecu out and it just wasn't a practical option for me. I appreciate all the time Tom from Champion has spent on this forum describing the 68s but he did stop responding to my PMs a couple of months ago. Guess I reached my limit, lol. No biggie, I meant what I said when I wanted to stick with vtgs and stock boost control so I looked and looked for performance numbers on pumpgas and finally decided that I would get the turbos and THERE WILL be performance numbers on pumpgas. Some other guys promised pbox numbers but they either ended up selling their cars or just disappeared. Unless aliens come back for me or something happens there will be numbers once the tune has been finalized. I'm working with Dzenno of ProTuningFreaks and both he and Mitch from Cobb have been great and very helpful.


I'm on revision 3 of the tune and the car is STRONG! Running 94 octane Sunoco gas exclusively. It's easy to get desensitized to the performance of our cars when you read about guys doing 60-130 in 5s, 4s, and even 3s. I don't know how "useable" the power is in those cars but can say that the vtg powerband is wide and decent for just puttputting around as well as onramp attacks and rollon acceleration. More details to follow....

 

Do you have a .2 or .1? 6speed, Tip, or PDK? I'm assuming based on replacing the turbo inlet pipes, it's a .1.

Either way, thanks for documenting your upgrades with the turbos. I have a pair of spare .2 turbos that I'm wondering what to do with. I'll either sell them, or have them upgraded if there is a worthwhile gain. I'm not interested in losing my low end power though.

Looking forward to your updates.

 

Great to hear you finally decide to go with COBB, Mitch will not let you down

 

Just some observations of my own, I have a very similar setup to Bogg.

I got the AP going today with the help of Mitch, and am in the process of dialing in my new turbos as well.

Startup, part throttle, and general drivability on E85 is in an ENTIRELY different league with Cobb vs. my old Protomotive tune. That was really my only complaint previously, was cold starts were a little rough, and the drivability suffered a bit - although it wasn't bad. With Cobb the car runs so smoothly it really made it a joy to drive. I forgot how smooth these cars can run. Really good stuff.

Also my gas mileage is way up, I was averaging ~22mpg on E85 driving around today and logging some WOT runs. I was getting more like 13-15mpg previously on the Protomotive tune. I will probably start a thread of my own once I get some more data, but just wanted to share my impressions.

I don't have the boost turned up on mine yet. The "big" VTGs like the 68s definitely feel different than the stock turbos. With the stock VTGs the car feels like it just wants to rocket off at Warp 9 anytime you give it some gas. That is not the case with these, you have to ask for it a little more. Boost threshold on them is excellent, I was making very usable boost as low as 2500rpm which was great for passing, maneuvering, etc. Don't think of these as huge highway only turbos, they have great response. While they aren't as punchy as the factory turbos, the first time you put your foot down and go you won't care. I'm only running ~16psi right now and the car feels very fast. Based on the datalogs it is flowing somewhere in the neighborhood of 75lbs/min of air peak at that boost level.

 

Thanks Bogg - I'm looking to upgrade mine too, so this write up is timely.

 

subscribing for some numbers from Cobb and PTF on the VTGs.

 

It is a .1 6speed. Sachs II.5 clutch, .2tt intercoolers, AWE catless exhaust.

I don't think the low end power is any less than my previous 63vtgs. Those were just as good as stock vtgs at the low end. Graphs to follow...

 

PTF has amazing 60-130 time (7.1s) on just stock turbos with custom Cobb tune. My time was 7.2s on the 63vtgs.

The 68s seem to have a lot more midrange and upper end power than the 63s, and no less power down in the 3-4k rpm range. I think my technique for pbox runs needs modification. I usually just drop the speed to about 55mph in 4th gear and punch it. It takes a tick before you feel boost and then off it goes. In real world driving with the 68s if I punch it the response is immediate and it takes off. Others have stated before that it is best to have a little "load" on the car before punching it and I think that is very true if you are going for best times.

 

My pleasure.

Your car is still one of the sharpest examples of a .1tt I've seen. It would be my second choice of colour. Even though a black car is a pain to keep clean it was my dream colour and hey ya gotta live the dream.

 

Or Dzenno at PTF.

 

Sorry for all the individual replies but I haven't figured out the whole multi-quote thing.

I think you will find after a few revisions of the tune the bigger vtgs take off just as willingly as the factory ones. At least mine do. The throttle mapping is definitely different with Cobb compared to Proto. The Proto one is a bit more "responsive" but my bro preferred the more linear Cobb throttle mapping. I'm going to try a few recalibrations to see what I like best, but different throttle mapping definitely contributes to the feeling of "instant response".

Your turbos should kick butt on e85, I look forward to the result and how they compare with these Champion 68s. Do you have 65 or 68 wheel? It sounds like your old tune was too rich? That would explain the rough idle and the poor gas mileage I think.

The Cobb idle is very smooth. I can tell it is much leaner than the Proto one - it smells less (lol), and is just a little more touchy off-idle (easier to bog). Todd from Proto had told me he had made the idle a little richer to have a smoother takeoff and it was true, but I prefer the less smelly option.

 

Subscribed
i also just picked up set of 68mm vtg should be ready next week also on e85 Cobb tune

 

Woo can't wait!

-Mitch

 

Quite a few of us doing big VTGs with Mitch this week.

 

You are so lucky to have e85 - "corn on the Cobb"! The 1k injectors will be perfect for the 68s with e85, and I KNOW you will hit sub 6s 60-130. Keep us posted on your impressions. I think you had bigger vtgs at some point before, right? (63s or 65s?)