[tomasp001]

Greetings,

I'm buying parts for the single turbo conversion. I got a used top mount hot parts kit from docrace locally. Now I am looking to buy a precision ball bearing turbo. 6266/6466

Please forgive my lack of knowledge with turbos, but I did do some research. Correct me if I'm wrong, but in layman's terms, Higher "A/R" means "Higher lag" but give better top end performance and lower A/R means "less lag"?

Also, please verify the correct "Turbine Housing" option to be compatible with the hot parts kit. From DocRace's description for their Hotparts kit is just "T4" did not disclose whether is "V-Band outlet" or "V-Band Divided outlet". (I will be shipping the compressor housing to T51R to add the T51R mod on it.)

T4 Inlet, V-Band Divided Outlet 1.32 A/R

What A/R are you guys running? or at the end of the day it does not matter, it's all about the tune?

[Leanped]

I can tell you about my car and maybe you can gain something from it.

I'm running a HTA3586 with a 1.01 Tial exhaust housing. It's a similar size to the turbos you're considering.

I get full spool by around 2.8k RPM. I honestly wouldn't care if it came at 3k or 3.2k because the sound the thing makes is nuts. You wouldn't really be able to notice the difference between 2.8 and 3.0k, so take whichever you want.

That being said, I don't really thing the limiting factor here is the A/R of the housings but rather the poor flow of the head at these high pressures. Unless you're getting a ported head, you won't be able to utilize the higher flowing housings at that high of an RPM.

In the end, I would go for a larger housing and consider head porting later on. If you want to go marginally faster RIGHT NOW, get the small housing.

[trb1]

I’m running a .84 ar 6062. Do you have a built block? I’d say go smaller so you have more street drivability.

[lightmanek]

I run 1.06AR on GTX3584RS, full spool at around 3700RPM (RON98) in 3RD gear, but turbo can spool from 2800RPM when boost breaking.
It's fun to drive even with manual at this hight rev. spool, but on a properly tuned auto it will be a non issue in any use scenario :P

[iqraceworks]

Originally Posted by lightmanek

I run 1.06AR on GTX3584RS, full spool at around 3700RPM (RON98) in 3RD gear, but turbo can spool from 2800RPM when boost breaking.
It's fun to drive even with manual at this hight rev. spool, but on a properly tuned auto it will be a non issue in any use scenario :P

That doesn't sound like it would be much fun as a daily driver......unless you constantly drive around with the rpms up over 3k all the time ?

[lightmanek]

Originally Posted by iqraceworks

That doesn't sound like it would be much fun as a daily driver......unless you constantly drive around with the rpms up over 3k all the time ?

It's a choice you have to make with N54, either go for low down torque with decent power or max. power with torque sitting higher in the rev. range.
For me there were many reasons I went big ST, one being me driving mostly motorway and high speed roads where power makes more difference for overtaking and acceleration from 40Mph and up plus I do frequent Autobahns where doing 150Mph is not illegal at all and fun to outpace all the sports and super cars there.

In city driving I occasionally miss small twins and responsiveness, but not to a degree to want to change my setup.

Friend of mine is building now a ST setup around G30-660 turbo with 0.83AR. I will have first hand experience of it in 2 months time, but knowing how my car drives now and what difference adding E85 makes to low down torque with my setup, I'm not going to change to small turbo any time soon. I will however try smaller AR at some point.

One more clarification, having big single doesn't mean no power at 2k or 2.5k RPM, it just means you have 150-250BHP and gentle ramp of power there. Car is really nice to drive on a sunny Sunday in traffic, but for sure, hooning requires faster roads as the fun starts from 3.5k RPM.

PS. With 8HP70 and Lamik TCU even hooning with my turbo lag would be a non-issue as the gearbox would take care of keeping car in full boost and the right gear all the time One day I will make that switch.