Hi,

i don't want to order the wrong one for my set up, im fully forged, arp bolts, 3 inch turbo to rear end etc 8:6.1 compression with 1.9L over bore. My question is I called up to order 6758 in 0.85 this morning and found out there was a 0.64 A/R for it which somehow I missed and they only have 0.64 in stock at the moment.

is there much difference between 6258 0.64 to 6758 0.64?? I'm using the car mainly on street but went top end 0.85 for them track days. Would the spool up be basically exactly the same but offer more up top than 6258 if I went 6758 0.64?

thank you

 

both of those turbos use the same turbine wheel, so the housings are the same.

spool on different turbos will never be the same though.


Its my preference to use smaller turbos with larger housings. but that's a separate topic for the internet to tell me their thoughts. I would stick with your plans to get the larger A/R 6258 if the 6258 compressor wheel will make the power your looking for.

 

OP, the vendor who is selling you the manifold for that EFR should be more than capable of helping with that question.

(hint, hint.)

 

its a kraken efr set up, I'm uk based so he is a little closer! Just custom fabricated so dosent know much about how the turbo performs!

I'm aiming for 350hp on 6258 or 6758 but as they are the same price basically if a 6758 will spool just as well but offer higher top end then that would be more appealing 0.64 than 6258 on the track.

 

To be blunt.

As a vendor, IMO, it is my responsibility to use the parts that I sell in such a fashion that enables me to do three things. First, I have to know the pitfalls of installation, so that I can help others if and when they struggle during installation. Second, I have to know that the parts are going to be reliable. I think allowing your customers to guinea-pig your parts is in poor taste at best. Third, I have to have enough experience to make specific recommendations to specific customers based on their specific use cases. If I can't help a customer select the right parts, then I'm not really adding any value beyond some metal.

If you are buying from a vendor that can't fulfill those three requirements, IMO, you're doing yourself a disservice.

We ship turbo parts worldwide, including to customers in the UK. have extensive experience with the 6258 and 6758 and know exactly when one or the other is called for based on the specific application. We also test our products in-house, extensively, and in a manner which few of our customers will ever match, let alone exceed. To my knowledge, the vendor your manifold comes from does not do any of this. Tread accordingly

 

No offence taken from the bluntness don't worry. I have pm'd you in this case to explain.