SR20det GT2871r upgrade untuned

[180sxqc]

Here's the situation:

I upgraded to a GT2871R on my stock ECU with all supporting mods. I ran the stock 7 PSI. I ran 3 months without tuning (3000km, no drag, drift, racing whatsoever) and the AF ratio was 11.5-11.8 up to the redline. (I have a wideband installed)

Do you guys think it might have caused a problem to the engine?

I noticed the cars runs a little rich on the startups (11,5-12) until temps goes normal then it's more 14.0 AFR on idle and 14.5 AFR cruising on light throttle.

I was wondering if it could be the result of the stock ECU auto recalibration (ECU is not chipped yet) due to the new turbo or maybe due to the spark plugs (I think they're heat 7) gapped to .30????

I am getting 555cc and Z32 maf installed and a new tune as soon as my car is out of storage.

LMK what you guys think, all inputs are welcome

For those that have negative comment please send me personal PM and keep the thread clean

P.S. I've been reading alot, most guys say it's ''bad'' for an engine to run untuned but I was thinking as long as the AFR ratio is OK then everything else is OK? Timing should probably be modified, I know, but how will that affect the engine health?

[fliprayzin240sx]

Just because the AFR is okay does not mean the ignition timing for it is good and its not detonating. There's alot more to tuning than just AFR...

[eklips3]

i had a buddy who ran a 2871r un-tuned and it turned out fine, AFR's were getting a little high but still safe.

if you only drove the car for 3000km and babied it then im guessing there should be no damage.

[4x4le]

Im not going to speculate wether your engine is fine or not, but i really want to know why people think the air fuel ratio is the key. While it may be important it is just 1/8 of the tune. Everything else is whats going to make or break you.

[cordobes]

Im not going to speculate wether your engine is fine or not, but i really want to know why people think the air fuel ratio is the key. While it may be important it is just 1/8 of the tune. Everything else is whats going to make or break you.

this ................. .

[canarygarret]

Hey, maybe we have some wear, but if you have not submitted to race not think you should worry about, just say that you should blow out to 8.7 psi

[tabasco122]

also, get 740s at least, the 555's will be maxed out before the turbo, and you dont want your IDC above 80%

[180sxqc]

I am not planning to run high boost 16+ this summer, i just bought a bare engine and i plan to work on it next winter so i dont gave tonpull out my actual motor

Should be 10-12 psi this summer, its going to be plenty for a summer ride imo

Thanks for the inputs guys, keep them coming!

[tabasco122]

fuel injectors arent something you want to skimp on, why buy something twice? you know you are going to want to boost more later

[180sxqc]

fuel injectors arent something you want to skimp on, why buy something twice? you know you are going to want to boost more later

I know, I had a deal on STI injectors (the 555cc). I had a really good deal and it's plenty for what I need for this summer. I will probably end up getting 740cc next year

[4x4le]

If you actually have someone that knows what they are doing tune for you, the price difference between the injectors and the fact youll need a retune isnt worth it either.

Being cheap is very counter productive.

[codyace]

Being cheap is very counter productive.

'but it was a good deal'

'but my cousin had them from his XXX car'

'but they were on ebay'

'but it's all i can afford'

...all of that stuff perplexes me. I absolutely can not (and will not) ever understand why people use any of the above 'excuses' as to why they did something half assed or wrong.



Sell the 555's, get the 740's, tune it once, and be done. Why pay to do it twice? As they say, if you have the time to do it twice, you have the time to do it right.

[codyace]

also, get 740s at least, the 555's will be maxed out before the turbo, and you dont want your IDC above 80%

Eyh, that really doesn't apply so much to modern injectors. SOme of the older MSD/Rochester 50 lbers had issues with big duty, but that's all but a thing of the past now. Plenty of guys running 90/95% for years now.

I personally have my 615's at 90%, and have for 4 years myself.

[180sxqc]

As I am planning to raise boost to 16 PSI max (12 psi daily), I was thinking 555cc would be enough for my power goals.. it's not a matter of cheapness here, but yes, I would rather save and paying less for affordable and reliable 555cc than paying more to get bigger injectors that I might not be using at their full potential....

[derass]

Good Thread. I had the same question.


I noticed the cars runs a little rich on the startups (11,5-12) until temps goes normal then it's more 14.0 AFR on idle and 14.5 AFR cruising on light throttle.
thats normal. it runs rich at idle to warm the engine up quicker

Just because the AFR is okay does not mean the ignition timing for it is good and its not detonating.
I believe the stock ecu has very conservative ignition timing as well as a closed loop knock control. this how you are able to gain power when tuning, by using more aggressive (advanced) ignition timing. if you run 7-10 psi (HKS actuator) you should be safe, as you could have boost set to be only slightly more charge air than a t25 at 11psi. the ecu would be able to compensate for that pretty easily as the OP and other guy above were saying about AFRs being 11.5-.8 at redline. this is still pretty safe. with a [email protected] and stock ecu i have nissans extra cautious 10.0-11.0 afrs at full throttle/redline. i read somewhere 12.0 is the magic number for turbocharged power production. ideally turbo engines would make most power at 14.7 (stoich) but rich fuel maps are used to cool the charge air and cylinders preventing detonation.

as for 555's vs 740's, i agree that it is more a preference of desired power. seeing as i dont not have an i/m or cams i will be happy with 300 whp and will be using 555's(also because i got them for a good deal lol). are there idle problems or bad fuel economy with 740's?