(Bit off topic) turbo lag...

[Joe Beninca]

----- Original Message -----
From: Joe <beninca at ains.net.au>
To: DIY EFI <DIY_EFI at lists.diy-efi.org>
Sent: Wednesday, 10 January 2001 11:09 AM
Subject: (Bit off topic) turbo lag...


>   I know it's a bit of topic and  I know it's been discussed many times
> before (read the archives!) but I would appreciate some advice.
>   I'm planing on turbocharging a Hillman Imp engine (a 930cc SOHC) with a
T3
> Garrett, which is bit on the large side for the engine. An intercooler
would
> also be used. The boost will be electronically controlled to slightly
> increase and flatten the torque curve. This is to keep the head gasket in
> one piece, allow a high static CR to be used and increase the toque at
high
> rpm to make as much power as possible. I'm hoping to allow the engine to
> usefully rev to 8,500 rpm.

You must start with a fully adjustable sequential ECU like Autronic for
accurate control on fuel and spark
You need to take care with water circulation to take out any "Hot Spots"

>   There seems to be two options to keep the turbo spinning between
> gearchanges:
> 1) Re-circulate the air from the outlet back into the inlet. This would
> occur during gearchanges and, perhaps, below a given RPM so the turbo
would
> spool up faster. However I am concerned that the turbo *could* be over
> revved.

Autronic has an antilag feature which is easy to implement.
No, the turbo cannot be over reved in an antilag situation with correct
control

> 2) Restrict the air into the turbo like a carburettored suck-thought
system.
> Could cause problems with oil seals and would increase the throttled
volume
> and so reduce throttle response. Perhaps two throttle bodies could be used
> in series?

The only way is to have too throttles in series as you have suggested but
controlled by the Before turbo throttle  ECU controlled as in the F1 turbo
days. Autronic has a mappable output for this purpose. This is too
difficult.

>   As the car is going to be fundamentally a road car but will also be used
> for hill climbs and sprints, keeping the turbo in one piece is of the
utmost
> importance! i.e. I don't want in inject raw fuel into the exhaust
manifold!
> ;) I have asked a Garrett main dealer for advice but they basically told
me
> they weren't interested (didn't want to be held responsible if it went
> wrong) and I should go to a tuning company (i.e. with a blank cheque).
> Many thanks, Toby

Use a ball bearing turbo and a correctly designed turbo exhaust manifold.
>
>
> --------------------------------------------------------------------------
--
> To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the
quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org
>

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org