I'm looking to move to a smaller turbo, just doing some research. Kind of up in the air, but leaning towards a 6765 or 6768.

 

not quiting racing are you?

 

nah, i'm just wanting something thats not some damn laggy like this T88. I'm finally getting tired of it. These newer turbos are making good power for their size.

 

how come no one has mentioned a GTX4294r?

 

I think its a little over kill for 600whp not to mention its about 1k more expensive than the 6768 and I'm sure spools slower on a streetport...

Chris

 

After a little more research, i think i'm in the same boat as you, either a 6768 or a 7168.

 

What's insane is that when I called a friend that distributes Precision etc he said that the 67 flows enough for 935hp but that the 71mm is only good for 985, an increase of 50hp but at the cost of a significant loss in spool. He went on to explain that if you look at the 67mm compressor, it is overall alot lighter than the 71mm, alot more than would be apparent based on the dimensions alone. He said the 6768 journal should spool like a 71 on BB with the same turbine wheel or at least be close...that is what spawned my interest on the 6768.

Chris

 

Are you planning on going journal or bb? The option for bb is salty.

 

Originally the I was going to go with a GTK-1000 based on spool (~3800rpm) and simply because its a BB turbo and I wanted that but the fact that this 6768 would spool faster on a journal bearing, reach the power level I want and cost 300-400 less makes me want it.

The issue with Precision BB units is that for the 68 and 75 turbine sides they cost 2200-2400 which is more than I wanted to spend on my goals. With that money you have a lot more choices turbine wise such as the GTX line from Garrett.

1450.00 for a 6768 that spools before 4000rpm due to a light assembly, is easily re-buidable because its journal, and is enough for 600whp+ sounds very inticing.

Chris

 

I'm with you, I don't think i can justify the cost of the bb.

 

i went with a bb 6765 will have some numbers very soon.

 

Cool. Please show the numbers when you get them...I'm interested.

When do you think you will have a dyno?

Chris

 

I've got a 6768 on the way. We'll see how well it works.

 

NICE! Please post some feedback on this thread as soon as you get it. I am about a month or two away from ordering my turbo and I'm very interested in your input.

What front cover did you get? What A/R? BB or not?

Thanks.

Chris

 

I got the bigger compressor housing, 4" in 3" out, and the .96 a/r hot side. Really there is only one way to set these up for a rotary IMO. I guess there are other hot side options out there for divided T4, but this will work. I went with the journal bearing. I would love to have a DBB, but the extra cost just isn't worth it to me.

 

Nice...

Essentially you got the hotside equivalent of a GTK 1000 which should be pretty nice on a 13b, with the lighter/more efficient compressor side of the PTE Billet 67...I am really interested in the outcome.



Chris

 

silverfdturbo, do you have the wastegate dumped out to atmosphere?

i have the 6765 myself. i have made 450whp at 18psi right now. to what some others have said the billet only gets moving above air 20psi so you will need high boost to get up in the hp level. i have come to find ill probably be stuck at 550-575whp at around 25-26psi. the 6765 turbine size is going to limit me there. the 6768 will be able to break the 600whp mark as you will be able to boost in the low 30's because of the bigger turbine. if i had known a bit better i would have picked up the 6768 off the bat.

 

also its tough to just pick a hp number every dyno is so different. trap speed and vbox times are a better indication of power. when i had 455whp on my 35r at 20psi i went 132mph. i didnt get to track it at 481whp but it would have been close to 135mph. a solid 600whp will go 140-142mph in the quarter.

 

SMG have you considered changing to a higher A/R ratio?

thewird

 

smg, what does your exhaust system consist of? 3 inch or 4?

 

i have a 1.00 a/r right now. a bit bigger would help some but not as much as taking the wheel size up. by the way marco seats look great in the car thanks alot.

my exhaust is 3.5"dp and 3" midpipe back with 2 straight through mufflers. not the most free flowing exhaust a 4" would help a bit but only with my wastegate flow as its rerouted through the exhaust. 3" exhaust can hold enough cfm for 600whp but a full external gate would be needed. i am going to pick up another dp from a-spec that doesnt reroute so i can see the difference in high boost. i did a test before and it was 17whp advantage above 6k rpms with a dumped wg at 15psi.

 

Glad you like them.

I can't wait to see the difference my full 4" exhaust and divided twin wastegates is going to make compared to the 3". Of course wastegates are re-routed .

I might end up switching to a 1.15 A/R if the new exhaust doesn't give me the flow to be able to shift at 8.5k at the track. Currently I shift at around 8k and peak power is maybe ~7.6k thereabouts. If I can shift at 8.5k while still making good power it would be quite beneficial for my lap times imo .

thewird

 

So will dual wg dumped be bad on a 4 inch exhaust system ?

 

Why would it be bad? Dumped wastegates is always better for HP. Only downside is the noise. Except with a 4" exhaust the benefits won't be as big.

thewird

 

Has anyone done a comparison between the 3 vs 4 inch exhaust?