Tune Necessary??

[grapejuice]

Be searching the forums a bit and can't seem to find the answer but I'm wondering how important/necessary a tune is? I've got a 90' GTR coming from Japan (through Feast), it's got exhaust including the front pipe, intakes and an EBC. Living in Denver the elevation is 5000+ feet, I just want to make sure the car is running safe...not trying to get the most power out of it. I've owned a couple STi's and I know it was important to tune after doing a turboback, just wondering if the same applies to GTRs or if the stock ECU can handle it?

[Skym]

With those mods, yes. Especially if run on lower octane pump gas. In Japan the fuel is around up to 100 octane.

Boost up mods and ECU tune can extract around 430hp at engine. That's if stock turbo's, engine are in good condition.

With N1 turbo's + boost up mods, which include say Nismo dump pipes, Nismo or Tomei 1.2mm metal headgasket (including Tomei metal intake gaskets), 260 duration Tomei Poncams, 600cc Nismo injectors, Nismo 255 lph fuel pump + hardwire fuel pump, Z32 AFM's x2 + plugs, ECU retune, Nismo or Tomei sump mods, looking at around 550hp at engine. Also clutch to suit (Nismo or Excedy twin plate), etc.

Might get more hp with cam timing changes (adjustable camgears) and running say a Link or Vi-PEC ECU with MAP, IAT sensors. Link, ViPEC ECU's have onboard barometric compensation, so can adjust to altitude.

With E85 compatble fuel system, E85 fuel, around 50-100hp more at same boost level.

Then there's cooling mods, brakes, etc to match.

[grapejuice]

Cool, thank you. I was figuring it would be best to tune but wanted to get some thoughts, I would assume the car was probably tuned in Japan but yes like you said could be on 100 octane fuel.
In checking with a couple of my local tuners that I've used before I'm looking at either Haltech or Power FC. E85 is a thought too, there's plenty of gas station with it here in the Denver area and that would require at least larger injectors and fuel pump from what I've seen.
I personally don't have huge power plans for the car, just upgrading turbos in the future but nothing big.

[hozer]

At a mile high, air density is 85% and you can NA engine loses ~15% power and a turbo to "THEORETICALLY" works 15% harder to force the same amount of air in, but willl make nearly the exact same power.

[grapejuice]

Making power here is definitely harder, at least with a turbo car it makes it's own atmosphere so you still get decent gains from tuning and mods. NA cars definitely suffer more. I'm not too concerned with power at this point, just want it safe and reliable.

[Dragon Humper]

You could give DIY Auto tune a call as well. They have plug and play MS3 Megasquirts now and one of them looks like it has a Nissan socket on it. The ECUs are very capable and offer sequential fuel and spark control...a far cry from their earlier boxes...the best part, $600 and the tuning suite is included. I will be going that route on my new project...shooting for 700whp.

They also have IAC control and a whole bunch of output control including boost, extra fuel pump, meth...etc. All based on whatever you want, RPM, speed, time....etc.


My car ended up in your neck of the woods...Colorado Springs.

Jon.

[Black BNR32]

it'll probably be fine, but yes, the gas difference could cause detonation. I never had my car tuned.

[grapejuice]

You could give DIY Auto tune a call as well. They have plug and play MS3 Megasquirts now and one of them looks like it has a Nissan socket on it. The ECUs are very capable and offer sequential fuel and spark control...a far cry from their earlier boxes...the best part, $600 and the tuning suite is included. I will be going that route on my new project...shooting for 700whp.

They also have IAC control and a whole bunch of output control including boost, extra fuel pump, meth...etc. All based on whatever you want, RPM, speed, time....etc.


My car ended up in your neck of the woods...Colorado Springs.

Jon.

Nice! I'll have to keep an eye out for your old car.

And thanks for the suggestion but I don't feel comfortable tuning. I'm leaning toward the Haltech option at this point since it will probably be better in the long run and I've used the tuner before too and have had really good experience.

[Skym]

Cool, thank you. I was figuring it would be best to tune but wanted to get some thoughts, I would assume the car was probably tuned in Japan but yes like you said could be on 100 octane fuel.
In checking with a couple of my local tuners that I've used before I'm looking at either Haltech or Power FC. E85 is a thought too, there's plenty of gas station with it here in the Denver area and that would require at least larger injectors and fuel pump from what I've seen.
I personally don't have huge power plans for the car, just upgrading turbos in the future but nothing big.

You're welcome.

I have tried lower octane than 98 octane and it knocked running 95 octane (stated as 96 octane but was really 95 octane) and ran on lower octane maps (combined with running engine leaner than it should have been with a higher boost level than stock).

If run E85 you need a GM ethonal contant sensor (or similar) so the ECU can automatically adjust tune to the fuel (needs to be setup by the tuner). So will need a ECU that has extra inputs (Link, ViPEC, Haltech, Motec, etc). The fuel system has to be methonal / ethonal compatible and that includes fuel lines, injectors, fuel pump, fuel tank (fuel cell or another fuel tank from another Nissan that is E85 compatible), etc.

Then basic boost up mods is all you need if not aiming for big hp and using for street use.

Around 460-550hp is nothing to sneeze at and is quite quick when have no wheel spin (4wd, semi slicks, etc). To me it feels similar to a mild tuned big block V8 when the straight 6 is at peak hp. You do lose lose a bit down low when compared to a big block, but that's normal with higher duration, lift cams, lower capacity straight 6 engine. Most switch to RB30 bottomend to help in solving lack of lowend and response problems with bigger turbo's, intercoolers, etc.