r34 engine rebuild

[joshuaho96]

34 minutes ago, WR33KD said:

I’m running 600whp on 98 and it’s fine, it all comes down to the final details of the tune and who builds the engine, the guys that built mine built some of the most bad ass RBs in nz. Any thing is possible with time and money.

Fill the car with 91 from an empty tank and do a few full throttle pulls if you want to find out just how good the tune really is.

OEM tunes and engines are built assuming that you will put in 91 RON at some point, maybe even indefinitely. They have to survive however many det events it takes for the ECU to pull timing to a safe level and keep running reliably without making EGTs go through the roof despite retarded ignition timing and rich fuel mixtures.

I personally do not have a great deal of trust in most tuners. From what I have seen many tunes out there are not very refined.

[WR33KD]

Why would I want to put 91 in it. To me that’s just dump and silly to do so.
If it’s tuned to run something that’s what you run.
Why don’t I just turn the boost up and lean it out

[KiwiRS4T]

3 hours ago, joshuaho96 said:

Fill the car with 91 from an empty tank and do a few full throttle pulls if you want to find out just how good the tune really is.

OEM tunes and engines are built assuming that you will put in 91 RON at some point, maybe even indefinitely. They have to survive however many det events it takes for the ECU to pull timing to a safe level and keep running reliably without making EGTs go through the roof despite retarded ignition timing and rich fuel mixtures.

I personally do not have a great deal of trust in most tuners. From what I have seen many tunes out there are not very refined.

This is just silly. High performance engines are tuned with a specific fuel - 98, race fuel of various sorts,  or if they have the appropriate sensors,  flex fuel. No one is going to fill such a car with 91

I do not know most tuners. I have a great deal of trust in the two tuners I have used on the basis of their known reputations built on results . I know there are other good tuners about because I have seen their work although I have no direct experience with them . Of course some tuners are not so good. The way to avoid them is never to go to a tuner because they are the closest or the cheapest but to do your research first.

[Dose Pipe Sutututu]

The only reason you run a particular type of fuel or octane rating is due to being knock limited from big boost, high IATs, timing, etc.

You want more power, but you're faced with knock, so what do you do? Go up in octane or jump to a different fuel such as methanol, ethanol, etc.

You can achieve big power on 98, but it depends on many factors, and generally all tied back to money.

[drifter17a]

well i do want to enjoy the power.

there is minimal point having 720bhp and driving it at 100 hp.

 

i will be flooring it most times and potentially put 3-4k miles a year. You will certainly have saftey mechanism built in such as if fuel pressure drops then back off or oil pressure drops back off etc but only thing that i can't monitor is the dodgy fuel injector.

 

how do you find out you have a dodgy fuel injector?

[Murray_Calavera]

Probably goes without saying, but a lot of the internet big horsepower cars have their motors pulled down about once a year. Maybe something needs replacing, maybe it doesn't. So yeah they say they are reliable etc, however I'm not sure if you are prepared to put 'pull down engine' as part of your routine maintenance.

As for your dodgy fuel injector worries, what ECU are you running? 

If you have a modern ECU, you will have engine protection that will cover it indirectly. A dodgy injector will show up when looking at AFR or exhaust gas temps. 

These 'safety mechanisms' you mentioned, I hope that isn't a gauge that you plan to 'monitor' while driving the car. Your ECU should be monitoring fuel pressure and oil pressure. If oil pressure drops from where it should be, I'd be setting my engine protection to be shutting the engine off, not 'backing off' whatever that means. 

[joshuaho96]

11 hours ago, WR33KD said:

Why would I want to put 91 in it. To me that’s just dump and silly to do so.
If it’s tuned to run something that’s what you run.
Why don’t I just turn the boost up and lean it out

Indeed, why would you do that?

OEMs tune their engines to run 98 too. The CR, cams, everything is designed to maximize efficiency and power with 98. The problem is you have people that take their brand new car and then decide to save a few dollars and put 91 in it. Even though that is an incredibly stupid idea people do it anyways. Another possibility is that you get a batch of bad gas or you drive out into the middle of nowhere and 91 is your only option.

A good tune needs to account for those possibilities and be able to protect the engine if it's a street car. If you're going full race and you're only ever going to pour fresh race gas into the tank then sure knock protection doesn't matter but these are real issues to think about for a street car.

[hardsteppa]

Maybe i have misread what yr saying, but WTF are you talking about? I have accidentally put 95 in once, when i still had the stock ecu...it did not like it one bit, and pinged. Oem tunes will not take running shit fuel just because 'its oem'. 

[Dose Pipe Sutututu]

Well the R33 ECU was calibrated for Japanese fuel not the junk here in Australia.

If you look at the tune on a S15 JDM vs an ADM theres a massive difference in ignition timing between the two. ADM has much lower timing vs the JDM which runs much more timing hence the power differences.

So no, manufacturers don't cater for all fuels, however they run knock sensors for when you run lower octane and your car knocks off it's tits and it lowers the timing (doesn't really apply to modded vehicles with ECUs that don't knock strategies in place OR when lazy tuners don't setup knock control).

[Kinkstaah]

10 hours ago, Murray_Calavera said:

Probably goes without saying, but a lot of the internet big horsepower cars have their motors pulled down about once a year. Maybe something needs replacing, maybe it doesn't. So yeah they say they are reliable etc, however I'm not sure if you are prepared to put 'pull down engine' as part of your routine maintenance.

I think it does need to be said a lot, repeatedly, everywhere, because it certainly isn't common knowledge/accepted truth that making big power on a RB involves reguarily tearing the motor down, especially with the levels of boost that E85 promotes on social media.

Also the LS Ecu has two timing maps, one for high octane and one for low octane, but all the car actually does is use how much knock it is reading to interpolate between the two maps, safe to say I don't really feel like putting 91 in the car ever.. even if it is "supposed to run on 91", even if the GM ecu is great at it, and it's OEM etc.. far more peace of mind putting better fuel in it.

[Murray_Calavera]

5 hours ago, joshuaho96 said:

Indeed, why would you do that?

OEMs tune their engines to run 98 too. The CR, cams, everything is designed to maximize efficiency and power with 98. The problem is you have people that take their brand new car and then decide to save a few dollars and put 91 in it. Even though that is an incredibly stupid idea people do it anyways. Another possibility is that you get a batch of bad gas or you drive out into the middle of nowhere and 91 is your only option.

A good tune needs to account for those possibilities and be able to protect the engine if it's a street car. If you're going full race and you're only ever going to pour fresh race gas into the tank then sure knock protection doesn't matter but these are real issues to think about for a street car.

I'm curious, have you put a car on the dyno, induced detonation and then watched the engine protection/knock control kick in? 

I can't imagine why anyone would happily fill a car with 91 after it's tuned to run on 98. 

How long do you setup your delay before you start reintroducing timing? 

What is the maximum amount of timing that your knock control can pull? Can that even eliminate detonation on 91 from the 98 tune?

At what rate do you increase timing after the delay event?

There is no way in hell I'd take an engine that is tuned on 98 and is knock limited, then put 91 in it and say, 'she'll be right. I have knock sensors, knock control and hell, I even have a plex knock monitor!'. No chance. 

Mate, sends shivers down my spine even thinking about it. 

[Murray_Calavera]

While we are at it, why don't we just stop tuning ignition maps? 

Set the whole thing to 40 degrees and let the knock control sort it out! 

[KiwiRS4T]

16 hours ago, drifter17a said:

how do you find out you have a dodgy fuel injector?

If you are going to have a mega KW build you could consider having O2 sensors for each cylinder.

When you assemble your engine get your injectors cleaned and flow tested. New ones should have flow information available. Then regularly replace your fuel filters.

[Dose Pipe Sutututu]

Or EGTs,  wideband O2 sensors pre turbo won't last long, will all roast to death.

This is why big builds (and HP) always run individual EGTs.

[KiwiRS4T]

58 minutes ago, Dose Pipe Sutututu said:

Or EGTs,  wideband O2 sensors pre turbo won't last long, will all roast to death.

This is why big builds (and HP) always run individual EGTs.

I stand corrected - never got to those heights myself...

[Dose Pipe Sutututu]

1 hour ago, KiwiRS4T said:

I stand corrected - never got to those heights myself...

Neither have I lol...

I rely on common o2 sensor and generally look at the plugs to determine the fueling across the cylinders (highly inaccurate) but then again all the cars I tune aren't really big HP cars nor are they big dollar setups so individual EGTs or O2s are generally out of the budget.

Funny enough a ZRE152R (and on wards) Corollas run pre and post CAT EGTs and also a wideband plus MAF, MAP and IAT, where as 90s turbo charged Nissans ran an AFM, 1x narrow band O2 and they still didn't go bang, also another reason why there is so much room for improvement to extract HP.

[drifter17a]

4 hours ago, KiwiRS4T said:

If you are going to have a mega KW build you could consider having O2 sensors for each cylinder.

When you assemble your engine get your injectors cleaned and flow tested. New ones should have flow information available. Then regularly replace your fuel filters.

How often would you change it?

[drifter17a]

4 hours ago, KiwiRS4T said:

If you are going to have a mega KW build you could consider having O2 sensors for each cylinder.

When you assemble your engine get your injectors cleaned and flow tested. New ones should have flow information available. Then regularly replace your fuel filters.

Are you referring to exhaust temp sensor per cylinder?

[GTSBoy]

2 minutes ago, drifter17a said:

How often would you change it?

Every 6 months to start with, cutting them open to see how dirty they are and lengthening the time a bit if they aren't real bad.

1 minute ago, drifter17a said:

Are you referring to exhaust temp sensor per cylinder?

He wasn't but he should have been.

[joshuaho96]

22 hours ago, hardsteppa said:

Maybe i have misread what yr saying, but WTF are you talking about? I have accidentally put 95 in once, when i still had the stock ecu...it did not like it one bit, and pinged. Oem tunes will not take running shit fuel just because 'its oem'. 

Modern turbo cars will be specced to run 98 RON but will also get by on 91. The instant they detect detonation they run the 91 RON tables. There will be a slow ramp back towards 98 but it takes multiple tanks of 98. If you interrogate a modern ECU with the right scan tools it will tell you the estimated octane/quality for each tank of fuel. If you live in California like me then the ECU will reliably complain about low quality fuel but the car will continue to run without audible knock.

I'm sure the RB26's OBD1 8 or 16 bit ECU is not nearly as advanced but even back in those days those ECUs would run wastegate pressure and altered timing/fueling tables when they detected knock.

Edited August 28, 2019 by joshuaho96