[Diy_efi] RB26 GTR stuff

Fri Jan 10 19:49:42 GMT 2003

Hi Bernd,

The engine has an OS Giken 3litre bottom end, gasflowed head, cams etc.

The gas flow to the head + bigger cams significantly changed the way the
engine consumes air and now shows lower boost but more power.

The cam timing also plays a part in when the boost arrives, more advanced
gives more torque and low RPM boost but looses BHP.

I will post later on the boost / RPM when I have a log.

Matt,

The exhaust housing is .64 AR, 53.8mm x 47mm turbine. Compressor Housing is
.6 AR, 51.2 mm x 71.1mm compressor.

The 2530 has 47.7mm  x  60.1mm compressor

The 2540 has 51.2mm x  71.1mm compressor which is slightly smaller than the
GT-RS spec above. Many people consider the 2540 a badly designed and laggy
turbo, whereas the GT-RS spec is supposed to flow more and have less lag,
sounds like having your cake and eating it too me, but we'll find out soon.

Hugh

----- Original Message -----
From: "Rausch, Bernd" <br at rnt.de>
To: <diy_efi at diy-efi.org>
Sent: Thursday, January 09, 2003 2:53 PM
Subject: AW: [Diy_efi] RB26 GTR stuff

Hi Hugh,

you have these turbos on a Skyline with a 2.7 L engine, right ?
At what RPM are these turbos generating boost, for example 3rd gear 1 bar ?

I am running 2 GT25 ball-bearing turbos (turbine 1.64/2.09 0.64a/r, T3-60
compressor) from Ray Hall (www.turbofast.com.au) on a 3L-24V V6 and would be
interested in upgrading them to bigger turbos (turbine 1.85/2.12 0.64 a/r,
1.94/2.80 compressor) which seem to be very similar to the HKS GT-RS.

regards,
Bernd

-----Ursprüngliche Nachricht-----
Von: Hugh Keir [mailto:hugh at sol.co.uk]
Gesendet: Montag, 6. Januar 2003 23:04
An: diy_efi at diy-efi.org
Betreff: Re: [Diy_efi] RB26 GTR stuff

I have fitted a pair of HKS 2530's with modified compressor wheels to make
the turbos the same spec as the new HKS GT-RS turbos that are reputed to
flow more than the HKS 2540 but have similar lag to the 2530's.

The HKS GT-RS is not yet available in the two bolt flange needed to fit the
GTR, but I wanted to see what they would be like anyway.

I used Garrett compressor wheels, some one told me that HKS have their own
castings which are fitted, I would have thought if there was something worth
knowing then Garrett would know, any thoughts?

Hugh

----- Original Message -----
From: "Matt Porritt" <porrittm at anet.co.nz>
To: "DIY-EFI" <diy_efi at diy-efi.org>
Sent: Monday, January 06, 2003 9:46 AM
Subject: Re: [Diy_efi] RB26 GTR stuff

What PC software are you using?
All else fails, may have to notch the crank pully and run a sensor from
there ;)
What turbos are you fitting to it?
--
Matt Porritt
RC Race Cars and Supplies
ICQ #22776813

On 6/1/03 11:36 AM Hugh Keir wrote

> HI Matt,
>
> Thanks for all your DIY responses.
>
> I am using PC software to interrogate the Apexi ECU.
>
> I have not investigated the quality of the signal from the trigger disc,
> will see how the plug gap changes go.
>
> Am also fitting some bigger spec turbos on Monday, so it's back to square
1
> again with the mapping.
>
> I imagine a cap in the right place might help but the trigger discs has
> discrete timing marks as well as cylinder marks which complicates things.
>
> Anyway thanks for your help and hope 2003 is a good year for you.
>
> Cheers
>
> Hugh
>
> ----- Original Message -----
> From: "Matt Porritt" <porrittm at anet.co.nz>
> To: "DIY-EFI" <diy_efi at diy-efi.org>
> Sent: Friday, January 03, 2003 10:18 PM
> Subject: Re: [Diy_efi] RB26 GTR stuff
>
>
> Power FC?
> Using the lappy software that¹s been developed in English??
> 1.5mm is HUGE.. The spark ill get blown out quick smart at anything over
> about 3000rpm with boost on it.
> What about using a smoothing cap in line or is the signal a waste of time
> and not jumpy?
> --
> Matt Porritt
> RC Race Cars and Supplies
> ICQ #22776813
>
>
> On 4/1/03 8:42 AM Hugh Keir wrote
>
>> Matt,
>>
>> I am using an Apexi ECU.
>>
>> I currently have a 1.5mm gap on iridium plugs which I will be changing
>> tomorrow, might try .8 and see if that clears the problem.
>>
>> The poor RPM is also playing havoc with my BHP spreadsheet as the BHP is
>> calculated from changes in RPM which need to be accurate for fuel and
>> ignition tuning decisions to be made.
>>
>> The engine appears to run fine, it is the logged RPM trace that is of
most
>> concern. The erratic trace is standard with the Apexi ECU.
>
>
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