GTR-Dad

Updated tune. Degreed cams. 3 degree intake and 10 degree exhaust correction expanded torque curve like a balloon. Torque comes on 200-300 rpm earlier, bumps peak from 330 ft.lb (445 Nm) up to 425 ft.lbs (575 Nm), and drops off less at 7500 rpm. Power at the wheels on a DynaPack 4 wheel dyno bumps from 390 WHP (290 kW) to 527 AWHP (393 kW) at 17.5 psi on my boost gauge and 16.5 psi (corrected for atm conditions) on the dyno. Setup is: VEHICLE: 1989 GT-R ENGINE: RB26DETT, 88mm bore, CR=8.7:1 MILEAGE: 20,000 Kms or so on engine OIL/WATER PUMP: Nismo/OEM OILING SYSTEM: Tomei Orifice, Tomei pan baffle, Greddy oil cooler and filter relocation INJECTORS: 600cc Nismo FUEL SYSTEM: Bosche 044 in-tank TURBO SETUP: twin GT2860R-5 MAP or MAF's: MAP INTAKE SETUP: Apexi Power intake, HKS hardpipes INTERCOOLER: HKS VALVETRAIN: JUN 264/264 9.7 mm lift - adjustable gears - Timing set to JUN spec HEAD WORK: Intake mildly ported and left rough, exhaust opened up about 15% and polished, combustion chamber polished EXHAUST: HKS dumps, Tomei DP, 85 mm HKS Priest BOOST LEVEL: 1.2 bar = 17.5 psi - Blitz Dual SBC Type R ECU SETUP: ViPEC Speed Density

I've been running the Nissan plug-in ViPEC on my R32 GTR for a couple of weeks and couldn't be happier. I sold my PFC including datalogit and Nismo MAFs for a bit less than I paid for the ViPEC and my car runs much better. I first installed my PFC on an OEM build and had absolutely no complaints. The car idled well, pulled hard, gave me all the control of fueling and ignition timing I needed. I added 264/265 x 9.7 mm cams and a set of GT2860R-5 turbos and everything was still great. Added HKS dumps, had some fairly extensive exhaust porting done and raised compression ratio to about 8.7:1 and couldn't get the PFC to control idle consistently. Part throttle shuffle was interfering with my life as well and could not be tuned out. Slightly off topic rant. Skip unless you're interested in why MAP>MAF sometimes... Root cause is that the MAF transfer function is nonlinear, and the PFC adds the raw voltages BEFORE it applies the transfer function. Oscillating airflow therefore appears to be oscillating load and the PFC changes fueling and spark accordingly. This feeds the shuffle and results in an unstable situation. If you could apply the transfer function to each MAF signal and THEN add them, the system wouldn't go unstable. Back to the ViPEC... It uses the factory CAS without any drama. The tuning went very smoothly with autotune every 500 rpm on the dyno making short work of fueling tweaks. (Innovate wideband feeds an aux channel for great accuracy and response time) We only layered on one more dimension to manage the differing fuel needs for part throttle vs WOT at a given engine speed and boost level. The car pulls nicely from the basement right to redline. The tune is pretty conservative running 10.5:1 at 17 psi in the higher rpm cells. More timing could be fed in as well, but the lack of knock control, or even indication of knock, makes me want to run conservatively until I get a handle on this. By the time you hear it from the driver's seat it's pretty bad... Don't want to go there. Anyhow, here's what my setup looks like with the dyno numbers. Cheers, Dan VEHICLE: 1989 GT-R ENGINE: RB26DETT, 88mm bore, CR=8.7:1 MILEAGE: 127xxx Kms OIL/WATER PUMP: Nismo/OEM OILING SYSTEM: Tomei Orifice, Tomei pan baffle, Greddy oil cooler and filter relocation INJECTORS: 600cc Nismo FUEL SYSTEM: Bosche 044 in-tank TURBO SETUP: twin GT2860R-5 MAP or MAF's: MAP INTAKE SETUP: Apexi Power intake INTERCOOLER: OEM VALVETRAIN: JUN 264/264 9.7 mm lift - adjustable gears HEAD WORK: Intake mildly ported and left rough, exhaust opened up about 15% and polished, combustion chamber polished EXHAUST: HKS dumps, Tomei DP, 85 mm HKS Priest BOOST LEVEL: 1.2 bar = 17 psi - Blitz Dual SBC Type R ECU SETUP: ViPEC Speed Density CLUTCH: ORC series 700 twin COOLING: Greddy aluminum rad with electric fan DYNO: Note linear torque increase from a respectable 150 ft.lbs @ 2500 to a slingshot-like 325 ft.lbs @4300 rpm, relatively flat plateau to about 6500 rpm and only modest drop in torque up to 7500. This is without any cam timing tweaks and with everything pretty darn warm. The car feels very alive on the road and willing to rev til you shift. :drive: Nice conservative tune intended to let me have a ton of fun without making rebuilds my hobby. HP: 390 TQ: 330

VEHICLE: 1989 GT-R ENGINE: RB26DETT, 88mm bore, CR=8.7:1 MILEAGE: 127xxx Kms OIL/WATER PUMP: Nismo/OEM OILING SYSTEM: Tomei Orifice, Tomei pan baffle, Greddy oil cooler and filter relocation INJECTORS: 600cc Nismo FUEL SYSTEM: Bosche 044 in-tank TURBO SETUP: twin GT2860R-5 MAP or MAF's: MAP INTAKE SETUP: Apexi Power intake INTERCOOLER: OEM VALVETRAIN: JUN 264/264 9.7 mm lift - adjustable gears HEAD WORK: Intake mildly ported and left rough, exhaust opened up about 15% and polished, combustion chamber polished EXHAUST: HKS dumps, Tomei DP, 85 mm HKS Priest BOOST LEVEL: 1.2 bar = 17 psi - Blitz Dual SBC Type R ECU SETUP: ViPEC Speed Density Nice conservative tune intended to let me have a ton of fun without making rebuilds my hobby. HP: 390 TQ: 330

Power gains on MAF-based systems often reflect redirected flow that 'hides' some of the air from the MAF resulting in slightly leaner mixures and more power. This is all OK if there's room for your EGTs to increase without hurting your engine, but pretending this kind of power gain comes from reduced flow resistance is just not right. I use the Apexi Power Intake, mostly because of the filtration results posted above. Cheers, Dan

I've read that cam gears can help with RB26 R32 OEM cams, but I haven't heard any stories about the R34 gaining anything at all. If you've got AM cams, will they already be tweaked to the sweet (timing) spot or do you still need adjustable gears? Dan

700 mm of Hg @ 0°C (where in Australia would you find THAT?) = 13.53 psi. Quote me. Dan

An increase in rolling diameter gives you a taller overall gearing. This, in combination with heavier rims of larger diameter will result in you feeling less torque. (Seat of the pants dyno is working!) Interesting thing on rotating mass... Imagine two wheels that weigh exactly the same, but one is a 19" and the other is a 16" (very light 19" wheel, right?) fitted with tires that result in the same rolling diameter. The mass moment of inertia (I=mr²) of the 19" wheel will be 40% greater than the 16". If the wheels are light enough, a 40% increase in 'effective mass' may be offset by benefits of stiffer sidewall or hawt looks , but directionaly you're making your car feel heavier. I've read that the performance sweet spot for wheel diameter is around 17 or 18 inches. I suppose this would depend on your car, but this is one case of 'bigger is not always better.' Cheers, Dan

I've heard the wastegate spring is adjustable, and that the factory setting is 1 bar. That's second hand info, so treat it as such. Dan

Thx for all replies. I understand the race series is not as wear resistant as the lower strength alternatives, but above 350 rwhp the strength is necessary. ACL race series with Calico coating it is! Cheers, Dan

As Paul said, knock over 60 is something to be concerned about. 120-200 would sound like someone pouring a bucket of gravel under your bonnet. If you heard abnormal sounds, it's probably knock and should be dealt with. If you didn't hear it, it's probably a bad sensor. If it IS knock, it could be a caused by a bunch of things, some of which are not the tuner's fault, but most of which probably are. Try some fresh gas before you get too worried. I wouldn't hesitate to fix it myself, but I like that sort of thing. If you paid someone to do a job, give 'em a crack at fixing it. Good luck! Dan

Check this link... http://www.crowcams.com.au/templates/Catal...cessories.shtml Not sure what they cost, but they've gotta be cheap. Dan

Jun recommends upgrading spring at lift of 10 mm or greater. Mine are 9.7 and the advice I've received is to happily use the OEM springs. Cheers, Dan

Sinista, Glad to hear they work well for you. What power level have you been running for how long? My only concern with the stronger bearings is that they may not be as durable. As with everything else in this game, you need to either try it yourself or find someone who's been there! Thx, Dan

The clearances will be shimmed to spec, but I'm not planning to upgrade valve springs. Good question though. I'm going to find out _before_ I fire up. Dan

450 hp isn't really _big_ horsepower. Reading manufacturers' info on bearings has made me think the Race Series will be strong, but not particularly tolerant of contamination. I'm looking for a reliable mid-power Rb26 and need some experienced voices on the power level you can run on the Aluglide bearings. Are they really more durable, or is just something the manufacture says to keep selling them? Thx, Dan

Hello All, I'm in the process of building an RB26 with the intention of making a daily driver and weekend track car with about 450 rwhp. Mods include: JE forged pistons Carrillo H Beam rods (overkill, but better too much than too little) Jun 264 9.7 mm cams Adjustable gears Metal gasket set Apexi Power intake Garrett GT2860R - 5 turbos Tomei dumps Aftermarket downpipes, not sure on diameter 3" exhaust Supporting fuel supply mods... I've heard good things about ACL bearings. Question is, for my application should I be looking at the Race Series, Duraglide, or Aluglide bearings? I like the idea of the Calico coating. Any negatives? Many thanks in advance. Dan

Are you running the Power FC? If so, just disable the closed loop feedback and run with bungs! If you get eager to optimize fuel economy (or if you guys need O2 sensors to avoid getting defected) you can fit O2 sensors later. Can't wait to hear how she goes! Dan

Not familiar with the Wolf, but the standard way to reset other ECUs is to remove power. I'd replace the coil and check the tune before I got too worried about other stuff.

I've changed from -7s to -5s! Time to order quick before I change my mind again!!! It's great to hear from guys who have actually got experience with a particular combo. My only concern was that a daily driver might not feel as snappy with -5s and with -7s. Drag racing isn't my thing and I didn't want to let the desire for big power numbers to cloud my vision. From Pete's dyno curve (400 hp at 5500 rpm) and description of driving experience, I can see that if I'm careful with the details I'll be able to get plenty of response out of the -5s and leave plenty of room to dial things up as my appentite for power creeps up. Cheers all! Dan

Thanks Pete. I agree with you completely and will PM with specifics. I can still change my turbo selection (I think) so will be very interested. In defense of my boost vs rpm turbo performance metric, I assume identically flowing engines. I like it because I can log it without being on the dyno. Cheers, Dan

Thanks for the info Pete! A couple things... 1 - I'd be willing to bet the reason some guys have seen no difference between rwhp and awhp is because they've used a 4 wheel dyno that connects the front and rear rollers so they roll at the same speed. Independent rollers won't work with the ATTESSA computer - it just gets confused. If the fronts and rears are rolling at the same speed the only source of slip is if the rears are losing traction on the roller. Not really a good dyno practice. The longitudinal g sensor will quite truthfully report no accelleration so ATTESSA will conclude there's no need to send torque to the fronts. They get a free ride. It still takes power to spin the front roller, but the car gets credit for doing that in the torque calcs. But it's in rear wheel drive. 2 - I too have searched hard for quantitative comparisons between the GT2860R in -5 and -7 trim. My car is a daily driver and weekend road racer so I value responsiveness highly. The math says the -7 will spool earlier and run out of breath sooner. The 300 - 325 rwkw ceiling is OK with me, so I'm planning to go with the -7 trim. I'd be happy to post boost vs rpm and dyno curves when the build is finished - maybe in late March - and would be interested to see your -5 numbers. My setup will be: I run a R32 GTR rb26dett with Garret gt2860r 707160-7 Apexi PFC and handcontrol Manual boost control JUN 264deg 9.7 mm lift JUN cam wheels ???cc injector ??? afms Apexi Power Intake Tomei O2 housings Turbo back 75 mm exhaust I'll be tuned for Canadian 91 (RON+MON/2) gas and running 1.2 to 1.4 bar of boost. Should be very close to an apples and apples comparison. I've got no doubt your peak power numbers will be higher, but I'd be very interested to examine the boost vs rpm relationship below 4500 rpm. Cheers, Dan

Canadian octane ratings are PON, which is (MON+RON)/2. We can get 91 PON anywhere and 94 in some places. 91-94 PON is probably comparable to 96-98 RON, give or take. JDM Mines tuned ECUs are not tuned for this fuel, but the OEM ignition retard smarts are still there and so protect us from ourselves. Dan

Sent. Have fun tuning! Dan

Here's some info I posted elsewhere in a Datalogit context. The "Inj vs Accel TPS1" area of the 'settings 2' tab affects the linearity of the Accelerate Injector settings. You don't want 100% of 'accelerator pump' settings to kick in when you just apply, say, a 25% change in throttle position. Nor do you necessarily want 25% of the extra fuel. The 'input' field is throttle position in units out of 256. (128 = 50% throttle) The 'setting' field is the fraction of Accelerate Injector setting out of 256 that will be applied give the partial throttle increase. There are three 'linearity' adjustment points, but be aware that there are two more fixed ones. (0,0 and 256,256) I've found that I need to set the first 'Input' box to a pretty low TP number (5/256) and give it a fair shot of fuel (175/256) to avoid leaning out under modest throttle increases. The PFC linearly interpolates between these points, so for throttle positions between the linearity adjustment points, you'll get a smooth transition. Hope this helps, Dan

You'll probably find that the PFC base map is a pretty good start. If you've got some tuning experience you'll be fine. I think people here are responding to what could be a guy who doesn't appreciate the consequence of missing the different tuning requirements of every car. A mate has worked extensively with Haltech and has commented that my PFC appears to be very capable. I don't think you made a mistake. You'll find tuning through the commander is a bit of a pain. I use the Datalogit system to connect via my laptop. If you want to see where I ended up before my fuel pressure went up, the offer to send a copy of my map stands. Cheers, Dan