pistons...... - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

T.F.S. · 7th November 2005, 08:53 AM

hi

i have seen a few kits around for turboing the RB25DE engine.....i have also noticed that (and this info could well be wrong) the compression for the RB25DE and RB25DET are the same?

i have also noticed that like the NA version the GTST pistons are also cast and look like a NA piston to an extent..

are the pistons actually the same on both NA and turo versions of that 2.5 engine?

if the above is correct what is stopping someone from bolting a turbo on and going for 400bhp?

regards, brian

Tundey · 7th November 2005, 06:21 PM

One correction,the compression ratios for the 2 engines are not the same and i would advise that before you do get all the facts.

Tundey

NISFAN · 7th November 2005, 11:08 PM

Quote:

Originally Posted by T.F.S.

hi

i have seen a few kits around for turboing the RB25DE engine.....i have also noticed that (and this info could well be wrong) the compression for the RB25DE and RB25DET are the same?

No DE is 10:1, DET is 9.5:1

Quote:

i have also noticed that like the NA version the GTST pistons are also cast and look like a NA piston to an extent..

are the pistons actually the same on both NA and turo versions of that 2.5 engine?

No, different pistons, but pretty much all else is the same. DE does not have oil squirters.

Quote:

if the above is correct what is stopping someone from bolting a turbo on and going for 400bhp?

regards, brian

Can be done but a fair bit of work required. Engine internals, ECU, fuel system, etc.

To get DET type hp out of a DE, you may aswell buy a used DET an sling it in. Much cheaper and easier IMO. You also need the stronger DET g/box if you want higher than stock power levels.

T.F.S. · 9th November 2005, 09:08 AM

Quote:

Originally Posted by Tundey

One correction,the compression ratios for the 2 engines are not the same and i would advise that before you do get all the facts.

Tundey

well thats why this thread is here mate!

im trying to work out if my engine is actually a turbo engine or a NA engine with a turbo bolted on the side.....

can anyone tell me waht the std NA piston looks like?.....i know mine are flat but i have not seen a NA piston to compare it to

any advice?

regards, brian

NISFAN · 9th November 2005, 09:26 AM

NA engine doesn't have Turbo oil return port tapped into block just above sump. Between cylinders 3&4 ish . Although this could have been added if engine was removed.

DET's have a different g/box.

What does the blue VIN plate say for engine: RB25DE or DET?

T.F.S. · 9th November 2005, 09:32 AM

thanks for the help mate!

the vin plate shows DE not DET......its a 4x4 phase 2 GT that i was told had a turbo transplant but after finding a NA ECU and loom and NA injectors i wonder.......

ill have to wait until friday till i can have a good look at the oil return, i know that the oil feed looks suspect as its a jubilee connection and not a threaded union (dont know what the normal type of connection is?)

i can do a compression test but that may not prove the case one way or the other..

NISFAN · 9th November 2005, 10:16 AM

Not really, they could have fitted a thicker head gasket to lower CR.

ECU's are the same except for maps, obviously. Perhaps possible to swap 'chip' only?

Loom is similar except for Fuel pump dual speed control, and turbo boost control, 2 wires (IIRC).

DE uses different injectors as you pointed out (red IIRC), and different capacity MAF (pink sticker?). I would check these to see whether you have turbo'd DE rather than DET conversion.

7th November 2005, 08:53 AM	#1 (permalink)
T.F.S. GTR Register Member Join Date: Feb 2004 Location: londonish Posts: 1,535	pistons...... hi i have seen a few kits around for turboing the RB25DE engine.....i have also noticed that (and this info could well be wrong) the compression for the RB25DE and RB25DET are the same? i have also noticed that like the NA version the GTST pistons are also cast and look like a NA piston to an extent.. are the pistons actually the same on both NA and turo versions of that 2.5 engine? if the above is correct what is stopping someone from bolting a turbo on and going for 400bhp? regards, brian

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7th November 2005, 06:21 PM	#2 (permalink)
Tundey GTR Register Member Join Date: Jun 2004 Posts: 337	One correction,the compression ratios for the 2 engines are not the same and i would advise that before you do get all the facts. Tundey

9th November 2005, 09:26 AM	#5 (permalink)
NISFAN GTR Register Member Join Date: Oct 2003 Location: Herts Posts: 1,696	NA engine doesn't have Turbo oil return port tapped into block just above sump. Between cylinders 3&4 ish . Although this could have been added if engine was removed. DET's have a different g/box. What does the blue VIN plate say for engine: RB25DE or DET?

9th November 2005, 09:32 AM	#6 (permalink)
T.F.S. GTR Register Member Join Date: Feb 2004 Location: londonish Posts: 1,535	thanks for the help mate! the vin plate shows DE not DET......its a 4x4 phase 2 GT that i was told had a turbo transplant but after finding a NA ECU and loom and NA injectors i wonder....... ill have to wait until friday till i can have a good look at the oil return, i know that the oil feed looks suspect as its a jubilee connection and not a threaded union (dont know what the normal type of connection is?) i can do a compression test but that may not prove the case one way or the other..

9th November 2005, 10:16 AM	#7 (permalink)
NISFAN GTR Register Member Join Date: Oct 2003 Location: Herts Posts: 1,696	Not really, they could have fitted a thicker head gasket to lower CR. ECU's are the same except for maps, obviously. Perhaps possible to swap 'chip' only? Loom is similar except for Fuel pump dual speed control, and turbo boost control, 2 wires (IIRC). DE uses different injectors as you pointed out (red IIRC), and different capacity MAF (pink sticker?). I would check these to see whether you have turbo'd DE rather than DET conversion.