Rb26 Build Not Enough Or Too Much

[magmazin]

OK guys, I have recently became the proud owner of a 1990 GTR with a relatively stock engine setup. It currently has an R33 RB26 in it with a chipped stock computer. It has a Trust FMIC, HKS hard pipes, Apexi air filters, 3inch HKS cat back exhaust, HKS twin plate clutch, and a Koyo radiator with electric fans.

Now I have been looking around online to see what guys are running for power and mods but I am not sure what I should be aiming for. My car will be street legal(one of the last cars to escape Motorex before they shut the doors) in Arizona. This car will not be my daily driver, more the weekend warrior/have fun at the track and woop up on vettes and such :-) I am interested in being able to drive it on the streets so I will not be gutting it and making it full race. I will be doing autocross and occasional drag racing. Not really interested in wheel to wheel but would like to hit some other track events. I will also be keeping the AC in since I am going to be in AZ(summers are killers here).

From what I have been reading 550-650whp(~400-480Kw) sounds like the sweet spot for an R32 GTR. I want to build a good powerful and reliable engine. I know the RB26s when built properly can run this kind of of power day in and out. Now I do not have unlimited resources to spend on my car so I kind of want to do it right the first time around, and heed the advice of others who aready went down the bumpy road.

BOVs, I am currently using the stock BOVs that recirculate the air. I like this setup, but I wonder when I crank the boost if it will be enough. Do guys ever add in a 3rd one? 2 stock ones recirculate and one vents to atmosphere. Or should I get a couple of greddy BOVs with the hose adaptors to recirculate? Just some thoughts going through my head.

Spark, ok at what point do I need to worry about getting more/stronger spark than stock? I have seen the splitfire coil packs along with other spark boosting modules. Is it a matter of how much boost I am running?

Too much power...yes there is such a thing even for GTRs. I have read at certain power levels things start to break on the GTRs. I've heard the trannies, especially 3rd gear go boom with too much power. I've also read/seen that the front diffs break and shear off the oil pan. OK, I know when your messing with big power and racing that things are going to break from time to time, but I would like to keep it to a minimum. Anyone know what this point of power equals loads of destruction is? Basically how much power can I run and not have to worry too much about other things breaking on me?

I have a pair of low mileage R34 N1 turbos (707160-4 I think they are the same as 707160-5). The int is A/R 60 M24 and the ex is .64. I originally bought them thinking they would work for me but it seems like everyone going this route is using HKS 2530s. Not sure if this is an HKS bling thing or if they are that much better. I've read that the R34 N1s are only slightly smaller than the 2530s. I would like to have a fat power band and be able to spool quickly. I have read conflicting information on the ability of the R34 N1s to put out more than ~500hp(~370Kw), although I've read some posts that say they are good for 700hp(~520Kw) at the crank. Problem seems to be most of what I've read is guys speculating not actual real world experience when it comes to the R34 N1 turbos(707160-5). However, if I am going to pay to have it tuned, I rather do so with the right turbos for my application.

I have also thought about installing either a Tomei oil pan baffle kit, a Trust oil pan upgrade kit, or a Tomei oversized oil pan(ouch this one costs bucks though) . Thinking maybe the Trust weld on oil pan kit. Somewhere I also read about using smaller orfice oil restrictors like what comes in the Tomei kit, and I also read some other stuff about having an oil line plumbed into the back of the head and I think returning to the oil pan. I already have a remote mount oilfilter setup, so I think I will go ahead and put in an oil cooler as well. I liked the idea of the ARC one that went in place of the grill just under the hood, however I was thinking since I will be doing autocross maybe I should get one that has an electric fan mounted to it.

The block I am going to have cleaned and honed and then have the clutch, crank, pistons, damper balanced. Anyone have experience with Eagle rods? do they need to be modified in any way? What about bearings, do they make a difference in who makes them?

Since the engine only has around 35k miles on it I was thinking of just leaving the head alone aside from slapping in a set of cams and cam gears. Is it worth messing with the head? I have seen some guys that had the quench(sp?) area ground out. Also I was just going to use the Tomei pon cams so I don't think I would need to reshim or change springs. Remember I am not try to be a dyno queen here, peak horsepower is not what I am after, I just want to have a fat powerband and be quick and responsive on the tracks. That's why I want to stick with twins.

Pump gas or race gas? I have read some people are getting great power out of there RB26 even on pump gas when tuned properly. Is it worth messing with 92 octane or mixing race gas with pump gas? I have heard some guys get it tuned to race gas and then turn down the boost when running pump gas. Pump gas is just easier to come by and way cheaper, but then again this isn't my daily driver. Any thoughts?

Any pointers from guys that have experience building and or tuning these engines would be greatly appreciated. I am open to suggestions, and if anyone knows of good shops that do dyno tuning in the Phoenix area that would be great also as I am not familiar with any out there.

Thanks in advance,

Tim Deesen

This is what I am thinking for a build:

Wiseco pistons standard bore

Eagle rods

ARP headbolts and rod bolts

ATI Crank damper

Tomei Poncams(not sure which ones) and Adj cam gears

Tomei 1mm hgasket kit with oil restrictors

Jun oil pump

N1 Water Pump

Greddy Intake Manifold

HKS style ex manifolds, dump pipes and collector

HKS intercooler hard pipes

HKS 3inch exhaust

HKS Twin Plate Clutch

Trust FMIC

Decat test pipe(or maybe get a good hi flow cat for the streets)

BNR34 N1 turbos (thinking about HKS 2530s)

Power FC L-Jetro

Z32 AFMs

600-700cc injectors

STR Fuel Rail

Aeromotive FPR

Apexi Air Filters

Electronic Boost controller

Nismo Fuel pump ~280 l/hr

Koyo Radiatior with electric fans

External oil cooler

Oil catch can

Am I missing anything?(other than a truckload of money ;-)...)

[BezerkR32]

350kw is ample for a tough street car. 400-500kw is more on the competition side of things, and more likely to break such things as gearboxes & front diffs. 350kw is achievable with standard internals, and the correct combination of bolt ons. Having said that if big power is what you are after, you have probably covered everything with the exception of oil pump. I would reccomend running an external mechanical oil pump rather than the Jun or N1 pumps. There are a number of upgrade threads on this site but i doubt if there will be many with 400-500kw output upgrades. especially still running factory options such as air & p/steer.

Good luck with your build, hope to hear how you go.

OK guys, I have recently became the proud owner of a 1990 GTR with a relatively stock engine setup. It currently has an R33 RB26 in it with a chipped stock computer. It has a Trust FMIC, HKS hard pipes, Apexi air filters, 3inch HKS cat back exhaust, HKS twin plate clutch, and a Koyo radiator with electric fans.

Now I have been looking around online to see what guys are running for power and mods but I am not sure what I should be aiming for. My car will be street legal(one of the last cars to escape Motorex before they shut the doors) in Arizona. This car will not be my daily driver, more the weekend warrior/have fun at the track and woop up on vettes and such :-) I am interested in being able to drive it on the streets so I will not be gutting it and making it full race. I will be doing autocross and occasional drag racing. Not really interested in wheel to wheel but would like to hit some other track events. I will also be keeping the AC in since I am going to be in AZ(summers are killers here).

From what I have been reading 550-650whp(~400-480Kw) sounds like the sweet spot for an R32 GTR. I want to build a good powerful and reliable engine. I know the RB26s when built properly can run this kind of of power day in and out. Now I do not have unlimited resources to spend on my car so I kind of want to do it right the first time around, and heed the advice of others who aready went down the bumpy road.

BOVs, I am currently using the stock BOVs that recirculate the air. I like this setup, but I wonder when I crank the boost if it will be enough. Do guys ever add in a 3rd one? 2 stock ones recirculate and one vents to atmosphere. Or should I get a couple of greddy BOVs with the hose adaptors to recirculate? Just some thoughts going through my head.

Spark, ok at what point do I need to worry about getting more/stronger spark than stock? I have seen the splitfire coil packs along with other spark boosting modules. Is it a matter of how much boost I am running?

Too much power...yes there is such a thing even for GTRs. I have read at certain power levels things start to break on the GTRs. I've heard the trannies, especially 3rd gear go boom with too much power. I've also read/seen that the front diffs break and shear off the oil pan. OK, I know when your messing with big power and racing that things are going to break from time to time, but I would like to keep it to a minimum. Anyone know what this point of power equals loads of destruction is? Basically how much power can I run and not have to worry too much about other things breaking on me?

I have a pair of low mileage R34 N1 turbos (707160-4 I think they are the same as 707160-5). The int is A/R 60 M24 and the ex is .64. I originally bought them thinking they would work for me but it seems like everyone going this route is using HKS 2530s. Not sure if this is an HKS bling thing or if they are that much better. I've read that the R34 N1s are only slightly smaller than the 2530s. I would like to have a fat power band and be able to spool quickly. I have read conflicting information on the ability of the R34 N1s to put out more than ~500hp(~370Kw), although I've read some posts that say they are good for 700hp(~520Kw) at the crank. Problem seems to be most of what I've read is guys speculating not actual real world experience when it comes to the R34 N1 turbos(707160-5). However, if I am going to pay to have it tuned, I rather do so with the right turbos for my application.

I have also thought about installing either a Tomei oil pan baffle kit, a Trust oil pan upgrade kit, or a Tomei oversized oil pan(ouch this one costs bucks though) . Thinking maybe the Trust weld on oil pan kit. Somewhere I also read about using smaller orfice oil restrictors like what comes in the Tomei kit, and I also read some other stuff about having an oil line plumbed into the back of the head and I think returning to the oil pan. I already have a remote mount oilfilter setup, so I think I will go ahead and put in an oil cooler as well. I liked the idea of the ARC one that went in place of the grill just under the hood, however I was thinking since I will be doing autocross maybe I should get one that has an electric fan mounted to it.

The block I am going to have cleaned and honed and then have the clutch, crank, pistons, damper balanced. Anyone have experience with Eagle rods? do they need to be modified in any way? What about bearings, do they make a difference in who makes them?

Since the engine only has around 35k miles on it I was thinking of just leaving the head alone aside from slapping in a set of cams and cam gears. Is it worth messing with the head? I have seen some guys that had the quench(sp?) area ground out. Also I was just going to use the Tomei pon cams so I don't think I would need to reshim or change springs. Remember I am not try to be a dyno queen here, peak horsepower is not what I am after, I just want to have a fat powerband and be quick and responsive on the tracks. That's why I want to stick with twins.

Pump gas or race gas? I have read some people are getting great power out of there RB26 even on pump gas when tuned properly. Is it worth messing with 92 octane or mixing race gas with pump gas? I have heard some guys get it tuned to race gas and then turn down the boost when running pump gas. Pump gas is just easier to come by and way cheaper, but then again this isn't my daily driver. Any thoughts?

Any pointers from guys that have experience building and or tuning these engines would be greatly appreciated. I am open to suggestions, and if anyone knows of good shops that do dyno tuning in the Phoenix area that would be great also as I am not familiar with any out there.

Thanks in advance,

Tim Deesen

This is what I am thinking for a build:

Wiseco pistons standard bore

Eagle rods

ARP headbolts and rod bolts

ATI Crank damper

Tomei Poncams(not sure which ones) and Adj cam gears

Tomei 1mm hgasket kit with oil restrictors

Jun oil pump

N1 Water Pump

Greddy Intake Manifold

HKS style ex manifolds, dump pipes and collector

HKS intercooler hard pipes

HKS 3inch exhaust

HKS Twin Plate Clutch

Trust FMIC

Decat test pipe(or maybe get a good hi flow cat for the streets)

BNR34 N1 turbos (thinking about HKS 2530s)

Power FC L-Jetro

Z32 AFMs

600-700cc injectors

STR Fuel Rail

Aeromotive FPR

Apexi Air Filters

Electronic Boost controller

Nismo Fuel pump ~280 l/hr

Koyo Radiatior with electric fans

External oil cooler

Oil catch can

Am I missing anything?(other than a truckload of money ;-)...)

[R31Nismoid]

A stock GTR motor will not last @ 350rwkw if circuit is the use.

Street it seems to be fine. But extended RPM of circuit work seems to aid in a much enhanced death.

I've seen a number fail near or around there power. They just dont last forever.

You have some great ideas Tim... i'll go over them tonight when i get home as there is a lot of info

[ferni]

heres my quick input.

Are you talking 400-480rwkw or crank kw? Don't forget the more power you want the bigger turbos you'll need = more lag....

BOV's, stock ones are fine - Leewahs car runs 600rwkw on stock BOV's.

Spark, probably worry about that once you get over 350-400rwkw.... can probably leave it until it needs it, you'll know.

power that things start breaking? tough one depends how hard you drive it, but at a guess around 350-400rwkw things would start to break..

those N1 turbos are probably good for around 500-600hp at the crank at a guess.

Yep i'd get an oil cooler, keep those oil temps nice and low.

Baffle kit/sump ext probably worth it. depends how much track work you'll be doing.

bearings not sure about brands etc... but i belive it does make a difference...

Head, thats up to you, I wouldn't stuff around with the flow of it, maybe have it cleaned up, as in pulled down replace anything that looks a bit worn etc...

Most of us just run pulp (premium unleaded petrol - 98RON here, think you may have different ratings in the states), race gas you'll get a heap more timing/power out of, but since you're not into competition i would stick to pump gas.

hope theres at least one thing here that helps

[fatz]

if your just doing drag racing and no circuit racing

i would say sell the gtr and buy a proper drag car

Edited June 22, 2006 by fatz

[paulr33]

avoid the N1 water pump, it pumps less water at lower RPM so its likely to increase the water temps when crusing through the hot hot arizona climate. the stock water pump would be more suitable