RB30 engine conversion (lots of pics) - Page 20 - GT-R Register - Official Nissan Skyline and GTR Owners Club forum

Cord · 28th January 2007, 09:18 PM

Can't see it being vastly different, but RB26's perform much better on a higher CR, 8:1 and above. Is it not poss to modify anyhting to raise it a little?

RB26's feel very sluggish off boost, and have a higher boost threshold with a low CR (Cue SteveN to tell me I'm wrong!!!!

)

R32 Combat · 28th January 2007, 09:59 PM

I wanted 8:1. I might get the block decked and re-ringed. I'll find out exactly whats what when I have the pistons.

fabianGTR34 · 29th January 2007, 06:34 AM

That's what I thought, and heard of some more people who lowered the compression ratio, in order to reach higher boost levels. Lowering the CR does seem to make the engine a lot less responsive. That would be a shame.. Didn't you remove the squish area allready? I would rather do other mods to fight detonation, such as removing squish area and polish the combustion chamber, and valves. And for high boost levels I would go a little bit under the stock CR but not much..

Bat-Fink · 29th January 2007, 08:07 PM

Amazing thread here.

Couple of questions though.

What is the full spec of the engine?Ie,rods,pistons and the like.

Finally,

what caused the need for another rebulid.

Keep it up.

kastin · 1st February 2007, 01:40 PM

You Guys are ceramic coating the pistons and combustion chambers arnt you?

It's definatly needed as there are no oil squirters.

R.I.P.S NZ · 1st February 2007, 09:15 PM

Quote:

Originally Posted by kastin

You Guys are ceramic coating the pistons and combustion chambers arnt you?

It's definatly needed as there are no oil squirters.

Says who? I have never had squirters on any RB30 even up to around the 1000hp mark, I've had 750hp engines do 40,000 miles and when opened up for a freshen up the pistons have been totally unmarked.

Piston oiling is not an issue in my opinion.

kastin · 2nd February 2007, 12:08 AM

All turbo rb's have oil squirters when they leave the factory, the rb30 has them on the rod,

His problems seems to be detonation, lowering the comp ratio to 7.5.1 is going to make it pretty sluggish and will need alot of extra boost to make up the power lost, i am sugesting a proven alternative to fight detonation.

cheap insurance for a new motor.

Asim R32GTR · 2nd February 2007, 12:46 AM

Quote:

Originally Posted by kastin

All turbo rb's have oil squirters when they leave the factory, the rb30 has them on the rod,

His problems seems to be detonation, lowering the comp ratio to 7.5.1 is going to make it pretty sluggish and will need alot of extra boost to make up the power lost, i am sugesting a proven alternative to fight detonation.

cheap insurance for a new motor.

I have to agree to this

R.I.P.S NZ · 2nd February 2007, 01:37 AM

His damage appears to be from detination and although coating parts may help in some cases its not an instant cure and "if you coat your parts you'll have no problems", correct set up and tuning of the motor is the key, coated or not.
I too would not go below 8:1, its easy to make a 8.2-8.5:1 motor run nice on pump gas, make good power and be responsive.

R32 Combat · 2nd February 2007, 07:08 AM

I will be coating the pistons.

After chatting to Mark @ Abbey, I've been advised to run, like Rob says, a compression ratio of somewhere between 8.2 and 8.5:1

Also, I was runnning almost 10degs too much ignition advance on boost, which might account for rather alot of piston damage.

So, obviously I'm still learning, but I'll get there in the end.

GTRSTILL · 2nd February 2007, 09:16 AM

It's simply fabulous that you a) have the budget to keep us entertained on this amazing thread and that b) you have a wife who is understanding to all this.

Does she realise your relationship is actually a threesome with an engine.

ExScoobyT · 2nd February 2007, 09:42 AM

`Also, I was runnning almost 10degs too much ignition advance on boost, which might account for rather alot of piston damage. `

How did you make that assessment? I assume you were listening for det? Are you suggesting you went past MBT timing with the low compression engine?

R32 Combat · 2nd February 2007, 12:44 PM

Well, after more talks, the timing might not have been as far out. The pistons, I guess, would have been totally destroyed if the timing was that far out.

A threesome with the engine?? There's no room for the wife here...

I'll have to look into this when it's all back together.

There have been no AEM gags in the last few days, whats going on? You bored already??

ExScoobyT · 2nd February 2007, 01:14 PM

flogging a dead horse (engine....???).......

R32 Combat · 2nd February 2007, 01:59 PM

Jolly good..

1st February 2007, 01:40 PM	#290 (permalink)
kastin New Users Join Date: Feb 2007 Posts: 3	coat or kaboom. You Guys are ceramic coating the pistons and combustion chambers arnt you? It's definatly needed as there are no oil squirters.

2nd February 2007, 01:37 AM	#294 (permalink)
R.I.P.S NZ GTR Register Member Join Date: May 2004 Location: Rotorua NZ Posts: 2,205	His damage appears to be from detination and although coating parts may help in some cases its not an instant cure and "if you coat your parts you'll have no problems", correct set up and tuning of the motor is the key, coated or not. I too would not go below 8:1, its easy to make a 8.2-8.5:1 motor run nice on pump gas, make good power and be responsive. __________________ R34 GTR: Quickest street trim skyline in NZ, 9.7 @ 137 on 1st test pass, first meeting in the UK, 10.4 @ 144. 240z, WRH8.71 / 162 @ 2 bar, stock crank, full street trim 1972 240z, RIPS RB30, quickest/fastest Jap street car in NZ 8.71/162mph 2 bar, No NOS, street tyres. RB engine building, alloy and stainless fabrication, affordable skyline tuning and high capacity repowers, worldwide shipping arranged. e-mail rips@inspire.net.nz www.ripsltd.com

Thread Tools
Show Printable Version Email this Page
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread:

28th January 2007, 09:18 PM	#286 (permalink)
Cord GTR Register Member Join Date: Aug 2002 Location: RB Motorsport Posts: 1,565	Can't see it being vastly different, but RB26's perform much better on a higher CR, 8:1 and above. Is it not poss to modify anyhting to raise it a little? RB26's feel very sluggish off boost, and have a higher boost threshold with a low CR (Cue SteveN to tell me I'm wrong!!!! )

28th January 2007, 09:59 PM	#287 (permalink)
R32 Combat New Users Join Date: Jan 2004 Location: Berkshire Posts: 4,341	I wanted 8:1. I might get the block decked and re-ringed. I'll find out exactly whats what when I have the pistons.

29th January 2007, 06:34 AM	#288 (permalink)
fabianGTR34 GTR Register Member Join Date: Aug 2006 Location: Netherlands Posts: 225	That's what I thought, and heard of some more people who lowered the compression ratio, in order to reach higher boost levels. Lowering the CR does seem to make the engine a lot less responsive. That would be a shame.. Didn't you remove the squish area allready? I would rather do other mods to fight detonation, such as removing squish area and polish the combustion chamber, and valves. And for high boost levels I would go a little bit under the stock CR but not much..

29th January 2007, 08:07 PM	#289 (permalink)
Bat-Fink GTR Register Member Join Date: Jun 2006 Location: Norwich. Posts: 46	Amazing thread here. Couple of questions though. What is the full spec of the engine?Ie,rods,pistons and the like. Finally, what caused the need for another rebulid. Keep it up.

2nd February 2007, 12:08 AM	#292 (permalink)
kastin New Users Join Date: Feb 2007 Posts: 3	All turbo rb's have oil squirters when they leave the factory, the rb30 has them on the rod, His problems seems to be detonation, lowering the comp ratio to 7.5.1 is going to make it pretty sluggish and will need alot of extra boost to make up the power lost, i am sugesting a proven alternative to fight detonation. cheap insurance for a new motor.

2nd February 2007, 07:08 AM	#295 (permalink)
R32 Combat New Users Join Date: Jan 2004 Location: Berkshire Posts: 4,341	I will be coating the pistons. After chatting to Mark @ Abbey, I've been advised to run, like Rob says, a compression ratio of somewhere between 8.2 and 8.5:1 Also, I was runnning almost 10degs too much ignition advance on boost, which might account for rather alot of piston damage. So, obviously I'm still learning, but I'll get there in the end.

2nd February 2007, 09:16 AM	#296 (permalink)
GTRSTILL GTR Register Member Join Date: Jul 2006 Posts: 1,533	It's simply fabulous that you a) have the budget to keep us entertained on this amazing thread and that b) you have a wife who is understanding to all this. Does she realise your relationship is actually a threesome with an engine.

2nd February 2007, 09:42 AM	#297 (permalink)
ExScoobyT GTR Register Member Join Date: Jan 2004 Location: `down sourfff Posts: 1,046	`Also, I was runnning almost 10degs too much ignition advance on boost, which might account for rather alot of piston damage. ` How did you make that assessment? I assume you were listening for det? Are you suggesting you went past MBT timing with the low compression engine?

2nd February 2007, 12:44 PM	#298 (permalink)
R32 Combat New Users Join Date: Jan 2004 Location: Berkshire Posts: 4,341	Well, after more talks, the timing might not have been as far out. The pistons, I guess, would have been totally destroyed if the timing was that far out. A threesome with the engine?? There's no room for the wife here... I'll have to look into this when it's all back together. There have been no AEM gags in the last few days, whats going on? You bored already??

2nd February 2007, 01:14 PM	#299 (permalink)
ExScoobyT GTR Register Member Join Date: Jan 2004 Location: `down sourfff Posts: 1,046	flogging a dead horse (engine....???).......

2nd February 2007, 01:59 PM	#300 (permalink)
R32 Combat New Users Join Date: Jan 2004 Location: Berkshire Posts: 4,341	Jolly good..