RB26 Compression Results.

[cbileske]

Yah, as far as I remember there was a few people on here with stock tunes on similar setups. It ran awesome for the most part up till late last season and starting of this year. A/f was always right where it should be etc. When I bought the poncams I read somewhere that they are the easiest cams to use with the rb. Shouldnt the stock tune be ok up till higher boost, bigger injectors, and trying for more power? The last thing I wanted to do was to try and have the engine tuned ontop of a issue. Thanks evilgtr. I appreciate all your input

[evilgtr]

With larger turbos you are running the same boost but the volume is substantially increased resulting in the ecu trying to compensate by correcting the fuel curve and timing. I'm not sure the limit of how much the stock ecu can correct but I would look at getting a tune asap. What size are your injectors ?

[cbileske]

The stock 444cc injectors. I understand under boost the ecu could have issues, but shouldnt it idle fine? I will dig out my consult cable and see what it shows.

[evilgtr]

If you had larger injectors I have ecu that is already tuned, when I picked up my car from ztune they reflashed my stock ecu with a nistune eprom chip (I think thats what its called?) anyways it tuned for shell 92 octane,264 degree 9.15mm tomei type b poncams,adj cam gears,N1 turbos @ 20psi and running stock mafs. But its tuned for 870cc injectors

[cbileske]

How hard would it be to tune for smaller injectors? Just need someone with the software to do it? Those are the correct poncams. I don't have adjustable cam gears was told not to bother with them.

[evilgtr]

What who told you that ? there is a very detailed thread on here about the advantages of aftermarket cams with cam gears. If you know someone with Nistune and you have your ecu socketed its actually quite simple and you dont need a dyno. They would also be able to data log while you drove around and looked over all the engines vital signs. Im not sure where Salmon arm is but I know gtrc has ALOT of very intelligent members in BC,some may be close to you. What are your plans for a ecu for your car ? are you going to run the stock ecu and mafs for abit ? You have a 550whp set up now (once you add injectors and cam gears) so a after market ecu might be something to look into. The stock R32 is very capable (garage Saurus had a R32 that was 780ps with the oem computer) but a aftermarket computer can help you datalog and fine tune your engine. How far are you from Burnaby ? I know Andrew from ztune has his own shop now and Jurie Human (one of the most knowlegable RB tuners in Canada) just started his shop in Vancouver to. I have both their cell numbers if you want to get ahold of them

[cbileske]

I'm about 5 hours from the lower mainland. I'm close to Kelowna and kamloops. I was really wanting to go with the aem ems, but right I've got to put my money towards other things, like a house; so I see a nistune being more the way I will go for a while. What would the cam gears do for me? Pm me some numbers and email adys if you have them. My work schedule gets extremely busy once all the snow is gone. Im pretty sure a buddy in kamloops does the nistune thing.

[cortexx]

I didnt realise he had cams in it , but at the same time , adding oil will seal the rings but i have never had oil seal bent valves or help with damaged valve seats . The oil test has always been the traditional method to give a basic idea of ring vs valve problem for low compression.

If it's misfiring , it wont be because of rings anyways, not unless they are letting so much oil through that they are fouling the plugs which isnt the case.

Does it misfire all the time ? just under boost ? when it's idling ?

[cbileske]

It is misfiring all the time, idling and increasing rpm; used to be only sometimes, but it wasn't due to boost. I thought that low compression can cause a misfire because of the air/fuel being messed.

[LuckyGTR]

compression ratio can be different for each setup depending on piston , head gasket and bore , correct me if im wrong!

i own a fully built engine wit cams and wen i took cp test i had 160-170 across all cylinders

i dont belive your engine could be that wrong if you dont even have or almost 10% difference on each cylinder

115-125 across all the same without 10% maybe your just really low compression and u could be running alot of boost

just need a good management ?

ennyways im not pro but thats my 2 cent lol

[evilgtr]

Hey I talked to Cam from lightspeed about your situation and he said for me to forward you his cell number so I will send it to your inbox,he is a great guy and will go into detail about your compression.

Il also forward Cam the link to this thread and he can share his experience and shed some light on the topic with actual facts

[LIGHTSPD]

First and foremost a compression test only shows a very small part of the picture. So many things can affect it temp, having all the plugs out, battery voltage, starter condition, cams and degreeing of the cams, gasket thickness, piston deck height etc so in our shop I don't even use a compression guage it just tells so little. Everything we do is based upon leak down because it will tell me if a cylinder is healthy and thats all I care about. Now if a cylinder is healthy and you have low power then we can check compression maybe somebody has the wrong combination of parts. Now the little bit that is being shown is that the engine is pretty much equal all the way across. With your setup you are 500 plus whp.

Ring gap is not going to affect compression with a couple thousands variation. I happen to know a couple companies have shown that a first and second ring set at more than .050 gap saw no increase in oil consumption. So it is better to keep the gap wider especially if you are running an engine on the edge. Not .050 but I usually set my gap 2-5 thous over manufactures recommendation just so that we have no issues.

I would be more concerned about your tune I personally think it is not wise running the stock ecu with that build you have you have spent a ton of cash on your motor and now are going to run the cheapest tuning solution you can find. You would be better off just waiting and doing it right doing it halfway basically costs double doing it right. You also have a misfire that needs to be addressed so many variables but the first one I think of is MAF's which a good ECU would get rid of (note I said good ECU most tuners you will find hate the AEM) If your engine has seen a lot of idle time you need to load it up but with a misfire that is impossible.

Cheers Cam

PS. Nice signature Jeff wonder who's saying that is LOL

[cbileske]

A new ecu is in the future, I resoldered the mafs last night, they didn't look bad besides the flux that was all over the board. You just resolder the points that orientate with the connector? So where they 90 into the top and the solder spots on the board. Is this correct? This has been a helpful thread thanks.

[cbileske]

Put the mafs Back in, checked grounds etc etc. Started it up, still missing. Have different coils in, pulled the connector off th #1 and it does nothing, the rest all do. Pulled that plug and it looks
Like it isn't gettin fuel, it should be wet since it isn't firing. That injector seemed to be getting fuel since it is weeping a little from the orings, maybe it's plugged up? Anyone in the Bc area have a good spare that I could try or buy? I want to get this misfire sorted out first, then put in a tuned ecu.

[evilgtr]

When does it misfire ? Under load ? What rpm range ? Is there a shop in your area you can have your injectors flow tested ?