Can't seem to get enough power out of built RB25DET?

Post by **eh?** » Tue Dec 29, 2009 4:37 pm

You have the odd ball CAS. I don't think that's the hitachi CAS. You might as well get a Mitsubishi CAS as you're going to have a fun time getting the aem wheel into that CAS. Something else is going on with timing other than a possible CAS issue. Your logged "ign timing" is not following "ign map". It may be a minor issue with the aem adjusting timing to correct an idle offset.

Post by **radianation** » Tue Dec 29, 2009 5:03 pm

It seems like the AFR used to be really good... 11-12 on pulls and around 13-14 normal driving. Would the cold weather change it that much?

Post by **flatrate** » Tue Dec 29, 2009 5:17 pm

If you dont have the Intake Air temp compensation tables setup correctly it could..

You should try and find a reputable tuner in your area

Post by **radianation** » Tue Dec 29, 2009 5:19 pm

I went with the best one around, or so I thought.

Post by **flatrate** » Tue Dec 29, 2009 5:39 pm

Well search more

Dont take this personally but, Tuning an engine isnt something everyone can do, i really think you should refrain from tuning it yourself... I'd hate to see you damage your engine from a couple "I think" key strokes

try searching in other forums or start calling around to get a better idea of what type of Tuning Facilities you have around...

Goodluck!!

Post by **radianation** » Tue Dec 29, 2009 5:58 pm

Does anybody know of a professional tuner in Louisville, KY / Indianapolis, IN, Cincinnati, OH / Lexington, KY, or some place very close to this circle? If they have experience with the Nissan RB25DET and AEM EMS and have a dyno I would be willing to go there today to get the tuning situation knocked out.
Modified by radianation at 11:28 PM 12/29/2009

Post by **radianation** » Tue Dec 29, 2009 8:06 pm

Nevermind that thought.
Modified by radianation at 11:26 PM 12/29/2009

Post by **boosted98gst** » Wed Dec 30, 2009 3:09 am

Hands down the best AEM tuner around is IPS motor sports in columbus ohio, they are a CERT AEM tuner and one of the best fab shops in the US right now. You can read about them in any import and domestic forum or magazine, they hold the 2 fastest C6 records and have tuned many RB motors Some reason columbus seems to be loaded with skylines or 240sx and 240z rb cars. They tune nothing but forced induction cars. If you come up here I would be more then welcome to meet up with you and go to the shop with you. 614.444.5884 http://www.ipsmotorsports.net ask for jeff tell him jason smith with the rb 240 sent you. If you decide to come up call me 937 243 5974.

http://www.youtube.com/watch?v=ooByV3j77To

ANYone in ohio can vouch for IPS .

Post by **Chaos the Xile** » Wed Dec 30, 2009 8:15 am

seems like you have everything taken care of to run over 500whp, what kind of fuel pressure regulator and fuel pump are you using??? They might be maxing out, also take a look at your injector duty cycle and the amount of fuel pressure you are running... I don't see why on 18psi you wouldn't be making mid-400s.

On my old setup i was making 407whp on 17lbs with a GT35, 720cc, and a walbro 255, and nismo fpr, when i got upward of 25lbs of boost the injector duty was maxing out because the fpr could meet the demands...

Post by **radianation** » Wed Dec 30, 2009 9:07 am

Awesome recommendation with IPS. Thank you.

I'm running a Walbro 255 fuel pump and a Nismo FPR. I have looked at the injector duty cycle in the AEM before but I don't know if there is something specific I should be looking for in this case?

Post by **radianation** » Wed Dec 30, 2009 10:18 am

I'm also talking with Injected Performance in Lexington, KY - does anybody have experience with them?

Post by **radianation** » Wed Dec 30, 2009 11:35 am

eh? wrote:unfortunately those runs aren't good. I know it gets scary, but the throttle needs to be all the way down (100%) for an accurate picture.

Hopefully this is a better attempt. I mashed the pedal in 3rd gear and let it get to about 7600 rpm before I had to brake. The road had a dip that almost threw me airborne! I did notice for the first time the knock sensor spiked!! =/

Log from 12-30-09
Modified by radianation at 1:49 PM 12/30/2009

Post by **spolitte** » Wed Dec 30, 2009 12:19 pm

radianation wrote:Awesome recommendation with IPS. Thank you.

I'm running a Walbro 255 fuel pump and a Nismo FPR. I have looked at the injector duty cycle in the AEM before but I don't know if there is something specific I should be looking for in this case?

Duty cycle is the amount of time your injectors are on vs the time they are off. 0% duty cycle means they are always off, and 100% means they are always on. As a rule of thumb, you should not try to push the duty cycle on your injectors past about 80%-85% or else you run the risk of starving your engine of fuel, running very lean, and going boom. The reason behind not maxing out your duty cycle at 100% and getting everything you can from the injectors is that when you start hitting %'s in the 90's then you run the risk of having your injectors 'float' at high rpm's. That is, the injectors will not be able to fully open or close before it is trying to do the other, so it will kind of float in the middle, and when the injectors are trying to pulse gasoline into the engine when they are only half open they won't be as effective as when they are fully open (won't flow the same amount of gas), thus you run the risk of not getting enough fuel.

Post by **eh?** » Wed Dec 30, 2009 1:35 pm

radianation wrote:
Hopefully this is a better attempt. I mashed the pedal in 3rd gear and let it get to about 7600 rpm before I had to brake. The road had a dip that almost threw me airborne! I did notice for the first time the knock sensor spiked!! =/

Log from 12-30-09

Modified by radianation at 1:49 PM 12/30/2009

You're certainly down on power. From 4300-5900 rpm (before you let off) my car is 1 second quicker with ~1psi less boost. Are you running a stock ratio diff ? Richen up your air temp correction a bit more, I need to do that too. Did you ever get that base timing correct? You may also need to pressure test your intake system and do a compression test of your cylinders.

Post up your .cal again.

Post by **radianation** » Wed Dec 30, 2009 2:09 pm

Thank you Spolitte for the excellent explanation of the duty cycle. I believe I read that in my tuning book awhile back and it makes perfect sense. I will check this again to see if I can figure anything out.

Yes, the initial timing is set correctly and that problem is resolved. The timing map on the other hand is still suspect and needs tuning.

I will check on pressure and compression tests. I sure hope the engine isn't doing something screwy since I spent a reasonable amount of time rebuilding it. Is there no way to review the MAP sensor readings from the AEM EMS logs?

*EDIT* I am running the stock S14 SE differential
Modified by radianation at 4:16 PM 12/30/2009

Post by **eh?** » Wed Dec 30, 2009 2:29 pm

Copy the boost section of my timing map to yours and see how it feels. http://www.240sxforums.com/for...9.zip

That's an older map and is a bit more conservative than what I'm running now.

radianation wrote: Is there no way to review the MAP sensor readings from the AEM EMS logs?

It's called engine load. You need to change your load units from kpa to psi. I thought your logs show a boost drop but it doesn't, it's flat.

Post by **radianation** » Wed Dec 30, 2009 2:40 pm

I will check it out tonight if I can. Thanks!

Post by **240slidekat** » Wed Dec 30, 2009 3:08 pm

when you use eh?'s timing map make sure you keep an eye on your afr's.

Post by **radianation** » Wed Dec 30, 2009 3:49 pm

I noticed that my AEM AFR gauge is reporting a little different from the AEM EMS. Is this normal?

Post by **eh?** » Wed Dec 30, 2009 3:53 pm

Connect the o2 controller power and ground wires to the power and ground wires for the ecu. See if that helps.

Post by **240slidekat** » Thu Dec 31, 2009 8:58 am

man your car is a mess!!! haha j/k

Post by **eh?** » Thu Dec 31, 2009 9:07 am

my car?

Post by **240slidekat** » Thu Dec 31, 2009 9:12 am

eh? wrote:my car?

no not your car, radianation's car. Your car is fine and dandy with lots of powah

Post by **eh?** » Thu Dec 31, 2009 9:36 am

Oh i thought you broke into my garage lol.I haven't posted pictures of my new fuel system but it's a mess with SS lines everywhere.

Post by **radianation** » Thu Dec 31, 2009 11:28 am

If you guys only knew the drama I've been through with my car over the past 2.5 years...

Actually, some of you might have read it from 240sxforums, but suffice it to say when I was talked into doing a swap when my KA24DE engine was failing I knew NOTHING about cars. I was allegedly getting an SR20DET swap and the shop came back from Ohio with a broken down RB20DET half cut instead (against my permission), which blew up in three months. So I bought a built RB25DET from Ebay and that turned out to be a 5,000 scam (came with a complete setup -- supposedly), so I built the engine and learned about everything only to find out each shop I worked with took shortcuts and half-assed most of the work. Since then I've been trying to do everything myself and have learned a lot, which is why I'm reluctant to go to yet another shop and have them do something for me. I'd rather try myself and break it than have somebody else do it for me. =/

Post by **spolitte** » Thu Dec 31, 2009 11:54 am

^^^ Man that sucks, and I definately know what you mean not wanting anyone to touch your car if they are not going to do it properly the first time. However, if you are lucky and really nice to the mechanics at a local and reputable shop (i.e. buy them pizza and coke while they are working on your car) they will often turn more friendly in a heartbeat, and might even let you look over their shoulder/help do the work properly when they wrenching away. On the other hand, some of them will remain set in their elitist 'i'm a better mechanic than you, so let me do my job in peace' attitude that really pisses you off, especially if you can see what they are doing is wrong or half @ssed and end up having to fix it yourself....

Post by **radianation** » Thu Dec 31, 2009 1:56 pm

What you say is the truth. I thought I had that relationship with one shop, but it didn't work out. However, the shop that works on my tires, brakes, and suspension is great and I trust him with all of my vehicles. If only he had a dyno and got more involved with tuning, etc.

He's the one that let me tear down my RB20DET when it blew up in his garage with his help. It was a great learning experience and taught me a lot. It made the whole process of taking a huge financial hit a little easier because I got to do something exciting.

Post by **radianation** » Thu Dec 31, 2009 2:05 pm

eh,

I used your timing map and it felt slower and yet faster, but at different times. Unfortunately, I couldn't get a solid 3rd gear pull because the roads are starting to freeze over. It will have to wait until the weather clears up again.

I think I copied the right cells, but I'm not 100% sure where in/out of boost would be on that timing map. I think I copied 2,500 RPM and higher to be safe.

Post by **eh?** » Thu Dec 31, 2009 2:19 pm

compare my timing map to the base line map and you can see the difference. You can run two instances of the aem pro to compare.For whatever reason they tuned your map with much less timing in the unboosted area vs the baseline map.

Remember keep your foot alllll the way down. Please be safe.

Post by **radianation** » Fri Jan 01, 2010 11:47 am

I like the compare feature. It showed me all of the differences across the board. Fascinating.

Can't seem to get enough power out of built RB25DET?

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