[Diy_efi] RB26 GTR stuff
Hugh Keir
hugh at sol.co.uk
Tue Jan 14 18:01:02 GMT 2003
Hi Bernd,
The OS Giken 3.0 kit is 86mm bore x 86mm stroke.
I am running with 8.5:1 compression, 260° inlet 10.25mm lift, 270°exhaust
10.25mm lift. The chambers are almost hemi with most of the squish
removed - the jury is still out on that idea, ports are slightly enlarged
using standard valves. Jun offer a 1mm larger diameter inlet, but most
tuners stay with standard. Twin DIY-WB for fuel analysis.
Combustion chamber and exhaust ports are ceramic coated, but I don't know if
it's still hanging on. It didn't last on the tubular manifolds. I wrapped
them with heat tape when I changed the turbos.
Engine set-up just now is exhaust cam timing has zero offset at 115° and
inlet is 6° advanced at 104°.
I mis-quoted the compressor sizes in my earlier post.
The 2530, 2540 and GT-RS have a common turbine 76 Trim - 53.8 inducer / 47.0
exducer .64 A/R housing
Compressor housings are common at .6 A/R.
2530 has 63 Trim - 47.7mm inducer x 60.1mm exducer compressor
GT-RS has 52 Trim - 51.2 mm Inducer x 71.1mm exducer compressor
2540 has 46 Trim - 51.7 mm Inducer x 76.2mm exducer compressor
The wheels I fitted are the GT32 52 trim ones in your link, I also do not
know the effect of the .6 A/R housing, although I have cleaned up the
compressor outlet diameter which has taken them to 1.6" from 1.55" which by
my calculations takes the compressor housing A/R to .64.
Did some mapping yesterday and am getting the following. I have also made
the fuelling a bit richer on the GT-RS set-up in an attempt to get the
turbos to spool earlier. I am running higher boost, but the actuators are
starting to confuse the readings above these boost levels. I have also
reduced the spark plug gap to steady the RPM data log, with the only
noticeable affect is make the idle a bit lumpy, the trace is still erratic
when on boost.
Boost 2530 GT-RS
0.3 3019 3192
0.6 3521 3930
0.9 3787 4295
1.2 4071 4500
1.5 4400 4700
The 2530 set-up gave 600BHP on a Maha Rolling road at 1.2 bar, but the
turbos would only give 1.5 bar at 8000 RPM, I hope the GT-RS will give
1.8 or more at 8000 RPM.
Cheers
Hugh
----- Original Message -----
From: "Rausch, Bernd" <br at rnt.de>
To: "List for general do-it-yourself EFI talk" <diy_efi at diy-efi.org>
Sent: Monday, January 13, 2003 8:46 AM
Subject: AW: [Diy_efi] RB26 GTR stuff
Hi Hugh,
according to hksusa.com the 2540 has the following configuration:
HKS GT2540 - 350 PS Output
COMPRESSOR:
-Wheel- 46 Trim - 51.7 Inducer / 76.2 Major
-Housing- 60 Inlet / 50 Outlet - 0.60 A/R
TURBINE:
-Wheel- 76 Trim - 53.8 Major / 47.0 Exducer
-Housing- T3 inlet / Internal Skyline Type oulet - 0.64 A/R
This seems to be a T04E-46Tim compressor.
The GT-RS has a GT32 52trim wheel, a compressor map can be found at
http://www.limitengineering.com/catalog.pdf , page 13. This map is for a .5
housing, I am not shure what the effect of the .6 housing HKS is using.
I would be very interested in details of your setup (bore/stroke, cr, cam,
valve sizes). Do you mind to share ?
Regards,
Bernd
-----Ursprüngliche Nachricht-----
Von: Hugh Keir [mailto:hugh at sol.co.uk]
Gesendet: Mittwoch, 15. Januar 2003 20:54
An: List for general do-it-yourself EFI talk
Betreff: Re: [Diy_efi] RB26 GTR stuff
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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