Help: Blitz Dual SBC Spec-R & Single Turbo

[monkey-fd3s]

Hi All,

Having a little problem with the single turbo conversion at the moment.  I am running a Dual SBC Spec-R and a HKS T04R .96 A/R

Boost is lazy to build and at the top end once it hits 14psi (we are trying to make 16-18PSI) the boost drops down rather than increasing.

The spec is:

Turbo: HKS T04R
COMPRESSOR:
-Wheel- 63 Trim - 66.7 Inducer / 84.0 Major
-Housing- 100 Inlet / 60 Outlet - 0.70 A/R
TURBINE:
-Wheel- 76 Trim - 74.2 Major / 64.7 Exducer
-Housing- T04 inlet / 65.75 outlet - 0.96A/R

Wastegate: Turbonetics NewGen
Size: 52mm
Spring: Currently 11PSI

Boost Controller: Blitz Dual SBC Spec-R
unsure of current settings

Does this all sound ok?  Anyone got an example of the settings they are using on the SBC on their single turbo or just some suggestions.

Cheers
Dave

[rx7veilside]

my guess is the boost controller is set wrong..ie it is reaching 14psi but not holding..the profec b has the tartget boost..the boost build and then a limiter to decrease boost for when boost peaks too high

[John Yorke]

Are you trying to run this turbo on a stock engine? You may find it is a bad match therefor slow to build and hold boost?

[bnaellis]

That turbo should be at full boost by 4000 rpm. Easiest way is to switch off the boost controller and just run off the wastegate spring if all of a sudden response is good then you know you need to look at your boost controller.
I have alos seen the same thing if you have aftermarket secondary injectors, if they are not seated properly in the lower intake manifold then the mixture sprays out of the injector slot and your boost drop off just as soon you reach full boost.

rgds

[monkey-fd3s]

Hi Guys,

Thanks for the replies

We did a little more investigating yesterday before taking the car off the dyno and found that at 4500rpm the turbo was producing 12.5 PSI of boost.  It appears the intercooler is too small and is losing 5 PSI across it.

Getting the intercooler re-engineered to have bigger end tanks and larger pipe work

See if that fixes it.