Just wondering how many degrees i should adjust my timing from the stock setting on my fairlady? I read in the workshop manual that they recomend not hitting boost if you have to use 91 octane. The best i can get out here in spruce grove is 92 and i dont feel like adding octane booster every time if i dont have to. I just got my new engine installed so i dont want to fry it
Thanks, Chris
94 at Husky … if it is actually better I dont know but I have not had any problems running it for the last 2-3 years in my cars …
VP race fuel if you are really worried …I run it in my cars from time to time and they run soo smooth … but $$$$$
retard 5 deg from factory is what I do. In ausie the auto wreckers that sell engines from Japan they have warentee for 1 month and what they do is retard it 10 deg from factory even so it would be next to impossable to blow your engine up. 10 is too much I say. Wont run too nicely. CHEERS!
sounds good. thanks for the help!
you should be fine with 91, 92 or 94! I run 94 and 91 in my GTi-R and have not had any problems…even when boosting to 1.1bar. I however have a FMIC so that helps with intake temps!
I would retard your timing or cheak what its at^^^^ or I can send you a picture of what your pistons will look like when you take a corner too hard with low tank or get a warn spot of air on WOT. 94 is better but not even close to Japanese gas standards.
its just like hard cornering with a stock oil pan and get oil starvation from the splashing back and forth …ARC/Trust ones are better
I WOULDN’T RETARD TIMING 5DBTC , if you motor doesn’t ping with 91 drive it ! If it pings than take away 1-2 deg off base timing. 5 deg off is a major loss of power , bad gas consumption and egt’s.
Same here, 5 Degrees is alot.
Like I said in my post I have a FMIC and the intake pipe is cold to the touch, even after high boosting. If it gets bad enough I have a water injection kit that will go in to decrease intake temps even more.
I warned you. Your at 1.1 bar aswell. I cant remember the equasion for compression at this moment but I think its for every 3-5 lbs boost pressure you would want another number off your compression ratio. A RB26 has too high and I mean too high compression for our shit gas. But its your car. I retard my cars and have no problems in performance. Ya you loose some but Id rather have 15 less hp that melting a piston or cracking parts. Plus RB26’s arnt getting easier to find. They are getting more rare and more expensive. This is why people ar running toyota engines in there nissans over in Japan.
1-2 degree’s is all you need. Five is a MAJOR loss.
okay. I’m just posting my opinion so im not mad or anything about your assumption so if you think I am wrong please state your facts on why. This is the type of stuff that should be getting posted anyways and I know I am not always right.
Now the equation is for every 14.5 psi you go up 3 more in your compression ratio. so if you divide 14.5 by 3 you get 4.83(psi) Now lets say factory boost on a SR20 is 8 psi so your running 1.1 bar so an est of 15 psi which is 6 psi more than factory. now I divide 6(psi) by 4.83 and I get 1.2422 which would be your compression raise from factory. Now the factory compression on a SR20 is 8.5:1 so you have to add the extra 1.2422 compression to that and not just that but also the compression gain from your factory boost setting. So all in all with a SR20 running 1.1 bar est 15 psi your final compression ratio would equal out to be a very close estimate of your 8.5:1 factory plus your est 3.1:1 compression gain from your raised boost pressure and that gives you 11.6:1 compression. Now that is too high for our gas in my opinion. When was the last time you see the mussel car guys have 11.6:1 compression on pump gas. maybe 10 but much higher than that and your going to run into problems. Now seen as you cant just change your compression ratio the one thing you can do to compensate is retard your timing. In my opinion 1-2 deg isn’t enough to compensate.
When I build my engines I take in factor what gas will be used which is 91 oct gas in Canada. Ya some places have 94 but not all. I also take in factor what boost pressure will be ran and that all depends on what I build the engine for. for the most part I would want a 7.2:1 compression for our gas so I can at least run 15psi in boost on a RB26 with lets me just say off the top of my head a 15deg base timing on 91 oct gas.
Go ahead and flame me. That rear equation is just off the top of my head. And also at first I thought you guys were talking about a GTR not a GTI-R and I have ran factory base timing on SR20’s without any problems at all. Though RB25/26 I have had knock with our gas. Best thing to do for a temp check is to also throw in a SAFC-2 as it has a knock sensor in it. When I hook up a GTR yo a AFC2 I detect some knock so ya just my 2 cents. As well RB26 and SR20’s do have the same factory compression ratio and boost pressure but the 26 is more prone to knock from the valve grind being different than the SR20’s and the squish pads having a different design. There is many things to take in fact that would take me a day to figure out equations to show you guys. Any who let me know what you guys think I guess. Cheers!
All i can say is Honda.
Most likely why they dont come turbo from the factory. Also most were made to run on 89 from the factory. Slap on a turbo with mild boost with some 91 and it should be fine. Alot of them are running more retarded timing or have a mds btm to retard the timing under boost
I understand what you are saying…you just don’t want us to F&*k our engines. My GTi-R’s SR20DET actually has a bit lower compression than you stated 8.3:1 vs 8.5:1.
So far running 94 and 91 have not been a problem for me. My car has not been knocking or pinging and I have not noticed the factory ECU retarding the timing for any reason. As I mentioned in my other post I have a huge FMIC to help keep the intake temps down…which it does very nicely. Also it is not like I run my 1.1 bar all the time…I usually use my 0.9 bar low boost setting for spirited driving but again it’s not like I am on boost for minutes at a time.
So all in all with a SR20 running 1.1 bar est 15 psi your final compression ratio would equal out to be a very close estimate of your 8.5:1 factory plus your est 3.1:1 compression gain from your raised boost pressure and that gives you 11.6:1 compression
Comp ratio is comp ratio whether boosted or not and most of the motorcycles these days (600 and 1000 SS especially) are running anywhere from 12.3: 1 to12.7:1 comp ratios and they run fine on our 91 gas.
Like I said above, I know what you are saying and I’m not trying to argue. Good thing SR20 parts are everywhere!!!
BUT back to the topic at hand…Z32TT, I think you should be fine. However keep an eye on things and if you car starts to ping/knock then retard the timing by a couple degrees and try again.
ya. I had a feeling that a GTIR SR would have different compression. The FMIC does help though but on a very hot day you still get heat soak. I don’t retard my sr20’s much as they never knock either but I am also running factory boost on all of them. The only problem I have had with knock is RB25/26. I have blown 1 RB26 with cracked rings and cracked pistons. I have also herd of about a dozen others that have done the exact same thing. If you look on GTR Canada you never see people rebuilding a engine unless they have to and its always a RB26. I also think that squish area has lots to do with it and the ITB’s The ITB’s actually split the air horizontal then when it hits the intake runner inside the head it goes up and down and mixes the air and fuel mixture different for valve to valve so the combustion doesn’t go as well as it should. On engines I will personally build for myself I take the ITB’s off the RB26 and weld on a Q45TB. I also change the squish slightly to match the valves. Some workshops get rid of it completely though I don’t trust that is a great idea unless it is specifically for race use. But as for the bikes running such high compression I cant say much about that other than its a bike and not a twin turbo sports engine. I am sure they have advances on knock sensors that adjust the timing when getting to 12000rpm but not for sure as I know nothing about a bike at all. As for compression being compression whether boosted or not I disagree. Throw 20psi into a RB26 on factory timing and bang instantly. That calculation of mine is correct and any workshop in Japan and ausie have told me the same thing. They take that calculation into every engine they build. This is for more reliable horse power as well. This is why we run 7.2:1 compression in or RB30. I can pretty much guarantee nothing compression related would make that engine go in Alberta. That RB30 we built was specify built for Canada and 9 oct for us to use as demo car for SEMA and NOPI.
But any who Z32TT I recommend slapping on a SAFC2. That way you can get some extra ponies and make sure your engine isn’t going ping. I get into lots of peoples cars and can hear it but they don’t so just a caution thing really and you cant say no to more HP. Autodream is very good at tuning them too.
I only get a bit of heat soak at lights or slow traffic but it goes away as soon as I start moving. It’s a HUGE bar and plate FMIC…
You don’t suppose he maybe has a HUGE FMIC huh? you only said it like 3-4 times in the this thread… Sorry I had to point that out :oops:
A properly tuned engine will run fine on 91 octane. Be careful running 94 octane ethanol blend on a 94 octane tune as flame front speeds are different than ‘real’ gas (I read this somewhere - can’t cite source - sorry!) and you need to tune for it if you want to run it.
The most reasonable information I’ve run across regarding ignition tuning is to first tune A/F ratio, then start really retarded. Do a dyno run. Advance timing and do another run. If torque increases and there’s no knock advance some more. Do this until you don’t make any more torque, then back off timing to the max torque at minimum advance setting. It’s a good idea to check your knock sensor output against a tuner’s ear on the dyno to build confidence that they work and to ‘calibrate’ output to an independent knock assessment.
Don’t count on hearing knock when you’re driving - destructive processes are not always audible. Pay attention to your knock sensors. Sooner or later you’ll get a tank of crappy gas and you’ll need to either take some timing out for that tank or stay off the sauce until the crappy gas is gone.
It’s not a bad idea to watch your exhaust gas temps either when you’re tuning and you want to avoid engine damage. Find out what critical temperatures are for your engine and stay away from them! (Richer A/F will run cooler. Ignition timing can affect EGT too. I don’t know the details, but understand that there are some fairly complex things happening. Best bet is to pay lot’s of attention when you make changes.)
Hope this helps.
Dan