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

[Chaos the Xile]

eh? i might be interested in sampling your timing map once everything is said and done with my build

[RustspecS13]

Really? Do you expect his timing map (at least any where above 50% throttle) to be any where close to what you'll end up running? :P

~Alex

[radianation]

I've contacted the local tuner who did the tuning without setting initial timing. He explained that while he could not confirm the timing he did take extra care to check how it responded when making adjustments and errored on the side of caution. He has agreed to take another pass at it with the timing now properly set for $200 or less.

Admittedly the car ran reasonably well on the initial tune, despite the timing inconsistencies. I'll be curious to see what the tune looks like after the timing map has also been set.

[eh?]

Just take it somewhere else. $200 is a rip off, he should be doing it for free.

[flatrate]

Any updates on this?

[radianation]

Hey guys! It's been awhile since I posted on this thread, but here I am months later with the same type of problem. Quick update:

The timing and fuel maps are set 100% -- I tried my best to get them going myself, but the car just didn't feel right ever since I replaced my coil packs and spark plugs. I had problems with my EVC VI boost controller as well. Basically, I just felt like I made too many changes and wasn't sure what was causing it. I scheduled a dyno tuning session with Injected Performance. Those guys are simply amazing, but we seemed to hit the same brick wall after cleaning up the maps.

The car put down 388 rwhp on a dyno dynamics (very similar to before) at 17psi. We all felt like something was holding the car up. In addition to this, we couldn't turn up the boost because it would misfire, so I'm diagnosing an ignition issue and hope to figure this one out. Regardless, 388 at 17psi with the S362 turbo seemed low.

The next day my turbo was smoking a bit. The seals finally went. Tonight I took the turbo off and I'm in the process of removing the head to get it cleaned up (flow bench this time, not the junky half-a** port & polish that was on it before). I'm going to put the new cams in and who knows what else...

That's where you can help. I need ideas why the numbers feel so low even after a kick a** tune? I'm hoping that the head just has some bad flow/turbulence because the guy who tried to port & polish it did it while it was attached to the block (before I got it). Basically, I think he just tried to port match it with the intake plenum. Also, I hope the cams help, but I haven't seen any solid numbers from people with the proof to back it up regarding each mod and what it contributes on these engines. Maybe I'm searching the wrong places? I tend to see answers like "slap on a turbo and you can get 500hp from an rb25det" as opposed to a dyno sheet and a list of mods. =/

btw - compression tests on the engine showed around 170 in all 6 cylinders.

Here is my 388 pull.

[youtube]http://www.youtube.com/watch?v=ewDcSZZIRxc[/youtube]

[radianation]

[Yellow4g63]

Double check your cam timing when you reinstall the head.

[GSDKinked]

SAU forum, and GTRcanada. US tuners tend to suck compared to the aussies and canucks. It's weird. Or you can hit up steve shadows.

[eh?]

SAU forum, and GTRcanada. US tuners tend to suck compared to the aussies and canucks. It's weird. Or you can hit up steve shadows.

His tune with 17psi and a medium sized turbo


VS
A Steve shadows tune - rb25 with a "gt45" sized turbo on 16psi


I don't know why everyone on Zilvia swings on shadows nuts, I've never seen anything impressive out of him. That dyno looks like utter crap. Why post that up on Zilvia and brag about it beyond me.
Rad, you should feel better after seeing that abomination.
lol

[Largekid]

I'm glad you have some good experience with injected. I am going to have them do the tune on my car as well as soon as its finished up...they worked on a friends TT G35 and it makes quite a bit of power

As far as your problems, I wish I could help out more. This is an ongoing saga of nightmares for you, lol.

[GSDKinked]

SAU forum, and GTRcanada. US tuners tend to suck compared to the aussies and canucks. It's weird. Or you can hit up steve shadows.

His tune with 17psi and a medium sized turbo


VS
A Steve shadows tune - rb25 with a "gt45" sized turbo on 16psi


I don't know why everyone on Zilvia swings on shadows nuts, I've never seen anything impressive out of him. That dyno looks like utter crap. Why post that up on Zilvia and brag about it beyond me.
Rad, you should feel better after seeing that abomination.
lol

1. I wasn't riding Steve's nuts.
2. I didn't say get a tune from Steve Shadows

I talk to him to get advice on combinations and etc. but when I really want to dig, I go to the AUSSIE forums. They have NO problem turning out power from these engines. And if I could read and understand japanese I would hang around their forum. There aren't that many people state side doing impressive numbers with the RB in terms of tuning. And I am going from what I've seen in the forums.

Most people tell everyone regardless of engine (SR, RB, KA and etc) just put forged internals, 740cc-1000cc inj, slap a turbo on there, 270 cams, springs, retainers, and blah blah blah and you'll have 800who.

http://www.skylinesaustralia.com/forums ... html&st=80

Go there and check out their numbers. And most are with moderate sized turbos.

[Yellow4g63]

SAU forum, and GTRcanada. US tuners tend to suck compared to the aussies and canucks. It's weird. Or you can hit up steve shadows.

His tune with 17psi and a medium sized turbo


VS
A Steve shadows tune - rb25 with a "gt45" sized turbo on 16psi


I don't know why everyone on Zilvia swings on shadows nuts, I've never seen anything impressive out of him. That dyno looks like utter crap. Why post that up on Zilvia and brag about it beyond me.
Rad, you should feel better after seeing that abomination.
lol

glad I'm not the only one to think so.

[radianation]

What's interesting to me is that my HP shows no time of stopping any time soon, and the boost was tapering off. There looks to be plenty of room to grow, like the engine is just stretching a little before the race...

The question is, how do I get there?

Thanks for posting the side-by-side. While I'm not satisfied with my numbers, it does make me feel a little better to know that I'm not terribly far off from some other people doing similar things with the RB.

I've got the whole car broken down in my garage right now, for better or for worse, and I'm going to just double check everything and make sure it's all done right while I wait for my turbo to be rebuilt.

[Carl H]

that steve shadows dynograph looks like absolute crap, i wouldnt even put my name to something that looked as janky as that.

randianation - do you have any dynographs of both power and torque, or do you have an afr vs hp/torque? what kind of final timing table did you end up with?

[eh?]

1. I wasn't riding Steve's nuts.
2. I didn't say get a tune from Steve Shadows

I talk to him to get advice on combinations and etc. but when I really want to dig, I go to the AUSSIE forums. They have NO problem turning out power from these engines. And if I could read and understand japanese I would hang around their forum. There aren't that many people state side doing impressive numbers with the RB in terms of tuning. And I am going from what I've seen in the forums.

Most people tell everyone regardless of engine (SR, RB, KA and etc) just put forged internals, 740cc-1000cc inj, slap a turbo on there, 270 cams, springs, retainers, and blah blah blah and you'll have 800who.

http://www.skylinesaustralia.com/forums ... html&st=80

Go there and check out their numbers. And most are with moderate sized turbos.

Did you bother to even read the previous pages? A LOT of good information was given there. The Nico RB forum is one of the better tech RB sites.
Most of those aussies barely work on their engines themselves let alone tune them, most of them just regurgitate crap that others say. And almost nobody other there has the aem ems.
Yes I've seen the RB dyno threads over there.... years ago. Been a member over there since `03 and stopped reading a few years ago. Most of them are "skyline owners", not "RB enthusiasts" like over here. Big difference.


Rad: You need to log a run so I can see if actual timing is being pulled back.

[flatrate]

Im another Low power RB owner, its gay, im on 20psi 3076R and only 412whp on a dynojet!!

[radianation]

The car is completely apart so unfortunately I can't log a run for you to look at right now. The only two charts I have are HP / Torque and HP / Boost. I might be able to get an AFR, but I was told during the tuning that those levels looked good and that there was more room to go for sure on that side of things.

I am thinking maybe there is some timing shift causing the issues because I have the AEM EMS and my CAS wheel might need to be replaced. I've had the "neck breaker" issue around 2800 rpm and a lot of people complain about timing sync issues under load. I've contacted AEM to try and get a replacement.

Also, I've ordered some poncams from Tomei. Nothing crazy, but maybe it will help open things up.
This is another user's picture, but this is the exact CAS I have. Does anybody know definitively which model it is and is it a series 1 or series 2? I have series 2 coilpacks, but this looks like a series 1 hitachi to me.

[Blown240sx]

Heres some more maps for reference.

This was a stock RB25 block/head
This was a daily driven car also
Mods:
Q45 TB
Greddy Intake manifold
740cc injectors
Equal length exhaust manifold
GT3076R
FMIC

Dyno Numbers were
363 hp
356 tq
@ 16 psi

[eh?]

The car is completely apart so unfortunately I can't log a run for you to look at right now. The only two charts I have are HP / Torque and HP / Boost. I might be able to get an AFR, but I was told during the tuning that those levels looked good and that there was more room to go for sure on that side of things.

I am thinking maybe there is some timing shift causing the issues because I have the AEM EMS and my CAS wheel might need to be replaced. I've had the "neck breaker" issue around 2800 rpm and a lot of people complain about timing sync issues under load. I've contacted AEM to try and get a replacement.

Also, I've ordered some poncams from Tomei. Nothing crazy, but maybe it will help open things up.
This is another user's picture, but this is the exact CAS I have. Does anybody know definitively which model it is and is it a series 1 or series 2? I have series 2 coilpacks, but this looks like a series 1 hitachi to me.

You should have logged the s-tooth values and check to see if it drifted. You can also do it with a timing light. My s-tooth values did drift with the old cas.

I'm pretty sure that cas is a different style mistu cas or it's atleast very similar internally. I think Krayton had the same one but I haven't seen him in a while. I believe he was able to use the aem wheel.

[flatrate]

any updates on this car?

[radianation]

Lots has happened since I last posted. I personally tore things down and upgraded to Poncams, adjustable exhaust timing, new CAS (to rule out any sync), new race cover on the turbo inlet, and smaller exhaust housing for quicker spool, and I did a coil pack conversion to LS2 Truck Coils (no more misfires above 17psi). Also did some cleanup in the engine bay (pic below). Worth pointing out that the sync appears to have been fine. The problem was the crappy RB coil packs. Super Sparks and liquid tape / insulating was not the solution. LS2 truck coils for the win!



The car is hitting some physical limitations right now around 421 RWHP on Dyno Dynamics @ 20psi pump gas. Without increasing the redline (which I need to upgrade my valve springs for) or running race fuel so I can hit higher PSI.... There is no more power to be made. I plan on doing both by the second week of January.

Dyno tuning charts and videos below. I would love to see some real world numbers on Dyno Dynamics from people with built RB25DET running at or below 20psi? I think we can all agree that just cranking up the boost on a built motor is a no brainer for big numbers, but that's not how this car will be driven 99% of the time. =)


Blue line = Yesterday's dyno run. Red line = back in June before the camshafts and other mods listed above. Notice the increase in power and the nice spool up difference? I do want to point out one strange anomaly we noticed during pulls. Do you see the little dip at the top end of HP? That happened about once in every 3 pulls. On normal pulls it was straight up and the curve kept pointing upwards. Timing was good, AFR was good, no boost leaks, it just made no sense?



Here is a chart from yesterday showing max hp and torque. Torque is up quite a bit from my tuning 2 years ago.



Here is the video from yesterday for proof.

[youtube]http://www.youtube.com/watch?v=hPoT_RHc0LQ[/youtube]


-----

Any help or suggestions are appreciated. I want to reach my goal, and while I'm getting closer i just don't see anything else that will make a huge difference without turning up the boost or increasing redline.

[julio]

You can easily make another 30hp by putting it on a dynojet!

[radianation]

I went back and revisited the Skylines Australia thread. It looks like after doing the KW -> HP conversion, I'm above 90% of the people on the 35 page thread with my current setup. Most of them at the top end are basically at the same HP as I am.

Is it safe to say that the RB25DET pump gas limit is around 400-450rwhp +/- on a dyno dynamics? If you see a dyno chart showing otherwise, please link it up. I admit that I skimmed the Skyline's thread looking for attachments, but there was a lot to go through.

[flatrate]

i still think something is wrong... your torque shouldnt be dumping off like that... looks like boost was consistant, revving the engine higher will not yeild you anymore power... you need to figure out why torque is dumping off like that... thats costing you a noticeable power loss... where your cams degreed? or just dropped in? what size cams?

What size turbine housing did you put on? T3 or T4?

[radianation]

Cams were not precisely degreed. T3 Housing. I have the Tomei Poncams. 256 / 8.50mm.
So you're suggesting where the torque is dropping off there is something wrong?

From what we can tell, the entire system is doing fine. Camshafts are breathing, Turbo has room to grow... Power is just not there.

[flatrate]

Torque shouldnt be dropping off like that, imo the cams are way off or there is an exhaust restriction someplace

[radianation]

The torque was a lot less and was dropping off more gradually in the 388 pull from June. seems like we have more torque now, but the rate of dropoff was a bit quicker. Every dyno chart I've seen shows torque dropping off at higher RPM? I will make sure I degree the cams properly when I put the new valve springs in. Any other tips would be greatly appreciated.

[julio]

I imagine the exhaust cam was adjusted on the dyno correct?

[nelson8708]

Wow, you've gone through a lot getting this car straightened out. IMHO i see two mods you could do that are relatively cheap to help you get closer to that 500whp mark. Either stay with pump gas and add a meth injection or if you have the fuel system for it and local access to e85 make the switch to ethanol. Either way i hop you get some smiles out of this car with all the drama its put you through.

-Nelson