I have had a good search, but couldnt really find the answer.

I have the XS Engineering T04S tubby kit, with a custom v-mount kit running on a large(ish) street port.

What I am wondering is, what sort of boost levels should I be seeing at about 4000rpm?

Thanks
Fish

 

is it a little laggy?

 

i have a t04s with stock ports, i see full boost (profecb set at 14psi) at 3800-4000.

 

Was expecting a power a little earlier, but once on boost the thing isn't slow.

Fish

 

With my moderate street ported engine, I can see 15 PSI by 3500 if I lug the engine (such as starting from 2000 rpm in 4th gear). In more realistic situations, I don't try to start pulling from 2000 - more like 3000. If I start at 3000, I probably dont' hit full boost till 4000 since the N/A part of the powerband pulls it up there quickly.

 

welcome to the wonderful world of single turbos!

 

we have a couple cars with the XS kit you have... they don't really come alive till over 4000rpms. they do pull good as hell tho once their going

 

What sort of boost should I be looking at running with one of these? It's set on low boost setting currently (still learning the single tubby power)?

Thanks
Fish

 

what is your low boost.. spring pressure? i wouldn't go higher than around 14 - 15psi on pump fuel. that will be plenty to get you in trouble hell one of the track dedicated cars we built was using this turbo at only 10psi. he had noooo trouble hitting 160+ mph on the back straight of vir.

 

Funny you say 10psi, as its either that or 12psi. Hoping to run about 14-16psi on high, with maybe water injection for higher boost settings.

Fish

 

I run mine at 10 PSI for low (spring pressure) and 15 PSI for high (405 rwhp). Mostly, I just leave it set on high

 

^^ How do you get both High and Low settings anyways?
Do you just tune your AFR's for your desired "High" boost levels and then back off the boost controller to get your desired "Low" setting?

I'm assuming these settings can be changed quickly (Boost Controller) without the need of reworking a fuel map to obtain a safe AF mixture? Thanks, D

 

Yeah I have a Profec B boost controller that is set for 10 (spring pressure), and 15.