# RB30/26 final tune feedback please



## leeroy_25 (Dec 19, 2006)

Okay guy's.. I have just had my final tune done on my RB30/26 and was hoping to get a bit of feedback on it and maybe some pointers to squeeze out a bit more bhp!. As ever we pushed for time at the tuners which was a shame as it could do with a bit more of a tickle. But I need to change a few bits as well so seems a good time to stop and get some other opinions!?

Quick spec breakdown
RB30/26
HKS264 step 1 cams
Standard RB30 bottom end lightened and balanced rods
Holset single turbo
60mm external wastegate
600cc injectors
Bosch type intank in pump (Good UK made copy!)
Stock intercooler
Stock FPR
Standard breather system setup rigged back into turbo inlet y-pipe after MAF's
Q45 Twin MAF's

Just to give a brief run down if you haven't seen my other thread:
http://www.gtr.co.uk/forum/149264-rb30-rb26-base-tune-done.html
My previous tune 2 weeks ago resulted in 370 rwhp(440 flywheel power) on the stock MAF's. I then swapped on some Q45 MAF's and got the map back to the same results all barr a little running issue where by it sometimes stalled when lifting off from high rpm and putting it in neutral. 
So this weekend we proceeded as follows. The tuner leaned out the map a bit at the top end and altered some of the MAF settings to try and cure the stalling issue. It is better but not perfect for sure. I also found out my Stock oil breather system setup was leaking through both one way valves! Air that is not oil! So even though it's a closed system I expect that won't be helping anything, especially when it's on boost!

Anyway, we stepped up the boost to 1.0bar and then 1.1bar and finally 1.2bar and the results are as follows:


























So just under 440bhp at the rear wheels and that was 6500rpm. (dyno rpm scale is out a bit) We opened up the rev limit a touch and you can see it starts to fall off the power after around 6600 anyway. Also the boost starts tailing back off to 1.1bar at the top end? It held 1.0 bar fine and 1.1 pretty well.. bt 1.2 it's struggling. maybe boost controller setup or the 10psi wastegate spring is not man enough? But in any case this is where I wanted it to make power as the low down power is what you can really use! I must say I was hoping to hit just over 450bhp to be close on 550bhp flywheel power. Maybe with some tweaks it can get there? This is where I would like some thoughts as to waht might be limiting me? Stock intercooler? Stock Fuel reg? exhaust?

You will see something a bit odd if you take note of the two runs shown...both runs were done one after the other with a minor top end tweak on the fuel map to lean it out but yet the second run the AFR map has jumped down (richer) over a significant portion of the run??? Anyone got any ideas what could cause this? I was wondering fuel pump running in tank bosch type with the Inline in tank pressure regulator still fitted? I have no gauge on it to check pressure at present? But that said I would have thought that would only really effect the very top end and the injector duty would go up which it didn't? Also it makes pretty much the same power?!

Could it be MAF related again, plugs or coils? The leaking one way valves on the breather system? Some ideas on this would help please if anyone has a thought! I am running the stock FPR for info. But was told ages ago that should be fine for what I am aiming at? 

Boost wise I am going to check the settings on my boost controller and also put a bit of pre-tension on the wastegate spring to try and hold it better up top. 

Anyway.. Let me know your general thoughts! I am happy but not ecstatic!

Cheers
Lee


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## leeroy_25 (Dec 19, 2006)

Okay guy's so I went back to the dyno at the weekend. Had no time to get a new wastegate spring. So I tried to put some pre-load on it. I had made a new MAF table for the Q45's and raised the airtemp correction value and also increase the warm water correction temp as the car never seems to get over 70deg and this seemed to solve the random problem of the car getting richer every run! My tuner then trimmed up the fuel some more (still running very safe) and did a few runs but still the boost was dropping off as the revs increased. In the end in a effort to try and get a representative run my tuner held half throttle to build the rpm up to around 5000rpm and then hit the throttle to try and get the boost to hold out for redline. Still no joy! Anyway. In the end I came away with 451bhp at the rear wheels. with the boost dropping off below 1.1bar! So would estimate at least another 10-15bhp if I could hold boost on the dyno. Annoying because it holds boost on the road fine!

Another graph and video below! I am pleased enough to call it a day now unless I have good reason to go back later! Essentially I am just chasing proof of a big number on the dyno!

































The whacky graph is from where we tried slamming the throttle at the end of the run! 

A quick little video clip too.. Not that great. But hey!


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## blue34 (Jul 28, 2005)

quote"Annoying because it holds boost on the road fine!"

That would suggest to me your not getting enough air through the car from the dyno fan. Boost is maybe dropping off as the intake temps get high, especially as you are on a stock intercooler.


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## leeroy_25 (Dec 19, 2006)

The air temps do go up the dyno which is the other issue.. Is it running in the mid 40's.. I have been told the stock intercooler should be man for the job by a number of reputable sources!?
The other possible issue is the wastegate spring is just too weak?? It holds 6.5-7psi boost on the spring only? But I guess if it was spring then it couldn't hold it on the road in that case?
Air temp and lack of air going in seems most likely. The filters are a bit crammed in a corner which won't help on the dyno! 
I may see if I can move them outside the engine bay at some point so they are running in cool air.
We will see.

Cheers
Lee


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## R.I.P.S NZ (May 7, 2004)

Do you own shares in a petrol station? Seems very rich.


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## godzirra (Sep 16, 2009)

What size is your wastegate Lee?

Apparently Dyno Dynamics reads lowest among the dyno types... it doesn't matter anyway as dynos are really a tuning tool and probably not wise to compare to others.

These RB30s are getting more and more popular, over here in Malaysia too. They are cheap to source and so far has been showing superb results.

If anyone is interested, here's my rb30 build which runs almost parallel to Lee's. You can say Lee has a hand in my build (although we've never met and are half the world apart) as I've used his sump adapter kit :thumbsup::thumbsup::thumbsup:

http://www.gtr.co.uk/forum/150560-most-travelled-r32-gtr-3.html#post1495508


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## mambastu (Feb 13, 2002)

Looks a bit rich to me too Lee. Have you got Datalogit ? If it were me I'd spend a few hours mapping it on the road and take it back for a quick dynorun if you need a figure.


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## leeroy_25 (Dec 19, 2006)

Hi guy's yes. I would agree it is a probably a touch rich.. Tuner and I both like to be safe! I assume I could safely take 0.5A/R out of it. I.e go mid 11's. I might to some road tunning a little down the road with my tuner. I don't have a datalogit though.
Also I have iffy idle again.. not compression this time though as that was the first thing I checked! Not sure if it is just too rich/lean low down and sooting up plugs or if I have a weak coil or something? Doesn't miss or mess about at all once you are on load and rpm. I am sure it was fine when I left the dyno but then it would have been red hot with high inlet temps!

By the way.. Can you run a 4WD (R33 V-spec) on a rear wheel dyno once the transfer shaft is back in?

Cheers
Lee


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## [email protected]y M/S (Feb 16, 2002)

boost drop off I would say will be the 

exhaust housing to small 
wastegate base spring pressure to small
too rich a mixture
restrictive exhaust 
low flowing cams/ set up

Your spec car could be tuned 12.5 AFR at max torque tailing off to 11.0 at max revs.

33GTR needs the front prop removed to allow it to run 2WD.


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## leeroy_25 (Dec 19, 2006)

Thanks for the feedback there..

So in other words I have no need to be dropping into the 10's? Doesn't the AFR curve normally go a bit richer where the boost comes in?

I will get a wastegate spring in due course. It held boost spot on up to 1.0 bar.

I am pretty confident the Holset turbine housing is adequate. If anything a little too large.

back box is something I have considered as the car is very quiet until the screamer pipe opens! The downpipe and back to the rear are all 3.5" pipe. might just whip the tail pipe off one day and see if it feels any better?!

Low flow cams I am not sure what you mean?
I have HKS Step 1 cams. I have timed them to get the power and boost response low down. not sure how that effects high end boost?

So I will be having the transfer shaft out again sometime then! Sod it!
I heard you could pull a fuse or something as long as you were not running for a prolonged period?


Thank you
Lee


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## hytech (Feb 26, 2003)

Yes 264 degree cams are too small for RB30. I run HKS 272 step 2 cams and make 700whp on only 1.3bar.


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## [email protected] M/S (Feb 16, 2002)

Lee,

tuning the cams to make torque will cause the motor not to breath top end and drop boost. Trying retarding the inlet cam off to see if the motor will rev out more.

I would tune the car to 12.5 AFR for peak torque and 11.0 ish high rpm. Once you over 25% throttle i will be down in the 12.0 AFR's as well.

The exhaust could be a problem thou drop the system off after the de-cat pipe or measure back pressure in the exhaust system to see if it limiting the exhaust flow a few Nismo system dont flow much gas.

Again measure exhaust gas pressure before the turbo to see if your getting high pressure this again will show either the exhaust housing is to small/ turbine wheel trim to small. If the pressure in the exhaust housing reads higher than boost pressure you wont hold the boost pressure.

hope that helps.

Anymore questions ask away


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## leeroy_25 (Dec 19, 2006)

Hytech.. 700hp! What rpm though?? bigger cams will produce more power at higher rpm for sure. Mine is a stock bottom end that I don't want to rev past 7k anyway. Also I was only looking to reach 550-600bhp gross power at the start and have a nice reliable torquey motor..

Abbey - I could try tweaking the cams again.. Do you think the wastegate is less likely to be the issue with holding boost on the dyno? Like I said it appears to hold okay on the road.. Certainly a hell of a lot better!
So at the top end my AFR is not too far out. maybe lean it out a few points but the low down range is very rich! It's even richer off load! I spoke to my tuner about coming out on the road one day and putting some time into trimming it out using an AFR gauge.. I think the issue has started because when I changed to the Q45's the entire map was way out.. and I suspect only the main used areas on load on the dyno have really been dealt with during the tune so the rest probably needs a good tweak now.. Might be easier to look at the overall map and scale and entire new map down or possibly a standard one is closer. Won't know until I get a copy of it to look at. Then I can go from there.

Looking at some other graphs I have seen I would say mine does have good low down power and torque compared to much high max power prints so it can't all be bad! Say around 4000-4500rpm. Maybe you will disagree?!

Appreciate the feedback and info.

Is there a special gauge to measure exhaust pressure?


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## leeroy_25 (Dec 19, 2006)

Just had a look under my car guy's and the rear box and presumably whole tail section are Jasma SR? Mean anything good or bad.. I also noticed that is has a secondary silencer box halfway back up the car which I must say I haven't spotted before.. Would probably be why it's so quiet? and maybe be a cause for restriction?

What d you reckon?

Thank you
Lee


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## leeroy_25 (Dec 19, 2006)

One more thing! I don't suppose someone could e-mail me an initialised RB26 Map that I can use to compared with my existing one and possibly start with. I want to get something that has been far less messed with than mine so I can maybe have a go at setting something up a little closer to what it needs to be before I go back on a dyno.

Cheers
Lee


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## [email protected] M/S (Feb 16, 2002)

Jasma is the Japanese Exhaust legistration company it isnt a make I afraid.

Q45 will need some major work on AFM curve , especially on part throttle/load I would say you could cut the load axis in half and it will still not use the whole load axis for what BHP you are trying to make. 

Cam work is best done on a dyno to work out what works and doesnt work.

Exhaust gas pressure measurement will need nothing special, we would just use the boost measuring set up from the dyno with a long piece of metal tube to take the heat away from the pressure sensor.

I am in the opinon you cant copy maps on you spec of car. You really need FC datalogit or something to alloow you to copy the map and look at it on a laptop. Using Q45 AFM'S will need a lot of work on the Air flow meter curve to make the car drive nice as I have said above already.

a quiet exhaust normally means restriction unless it is a well made special system. As I said get the car on the dyno and run it with the exhaust removed from the cat back.

You say it dont drop boost on the road , how are you measuring this? I bet it is dropping boost but your looking at a boost guage or controller which doesn't log the boost pressure?


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## dan0h (Jul 26, 2002)

That boost drop off has ALL the hallmarks of a restrictive exhaust, though given your standard intercooler, I'd be measuring pressure drop/buildup on either side of the I/C core just to eliminate it as a possible source... Boost drop off is very hard to measure and quantify on the road, as the drop off is likely proportional to how quickly the car is moving through the revs, but load it up in 5th (350rpm/sec) and I'd bet that its tailing away quite strongly.


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## leeroy_25 (Dec 19, 2006)

Hi guy's
Thanks again for further advice.. I think I will start by dropping off the rear section and see what I get from there.. I presume the restriction would most likely be in the mid box? In which case I could just cut it out and replace it with a straight section of pipe?
I googled Jasma and it came up as if it was a brand! Oh well.. No clue what it is then..

I am measuring boost off the EBC readout when on the road. it drops of quite low down the rpm range on the dyno and on the road it seems to hold the pressure at highish rpm in all the gears I have tried to look at.. 5th is a bit hard to get too many revs up!! Surely the EBC will give a reliable real-time readout??

I think I have the Q45 MAF table setup pretty good now.. I calculated one from common RB25 data and the car drives as smooth as you like on or off load. Smoother that it was with the stock MAF's the only issue you get is it try's to stall if you rev and go on the clutch. But that has also been pretty much sorted now.
I do have RB25 MAF's I could put on it but I don't think the Q45's are causing any issue to warrant that?

Cams I would only touch on the dyno of course if I need to..

And MAP wise I was not planning on copying a MAP. I wanted a standard unmolested RB26 map to see what it looked like so I can compare my inj table. If I have a load of wild readings I was think I could then globally adjust the fuel table so the main values are close as can be then add in or remove and big lumps of fuel as necessary.. Then go to the dyno load the map on and fine tune it from there. This also means I can load in all my Correct MAF table numbers and Injector details etc. Just trying to get the cleanest map I can and minimise on hours of dyno time!

Cheers
Lee


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## dan0h (Jul 26, 2002)

I can send you a totally bog-standard map from FC-Datalogit if you need it, drop me a PM with your email addy and I will send it over to you.

Oh and JASMA (if I recall) is the Japanese Aftermarket Sports Muffler Association. Or something along those lines.


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## leeroy_25 (Dec 19, 2006)

Thanks Dan.. pm coming. might be useful to have that Map.. Thank you.

Erm. I have the possibility of a Trust catback system.. Has a centre silencer bit in it.. Any good? I would guess a trust system should be pretty good?

Alternatively if it is just the centre box that causes the restriction I could just cut mine out if it proves to be the problem?

Would I be correct in thinking that if the exhaust is restrictive. If I drop it off I should actually get an increase in boost and maybe boost response as there will be less exhaust pressure pushing on the wastegate spring?

Thank you
Lee


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## Chris1983 (Dec 10, 2005)

There should be a number on the Jasma plate, I did a quick search on here as I remember seeing the list posted before, I hope this helps identify your system:

Quote:
Akiyure Inc. 047
Apekusera Inc. 048
Iida Inc. 130
Ikeda industry 003
A tea sea international Japan Inc. 074
Etching k s Inc. 051
Ebansupuranningu asuretsuku division 129
M-TEC Inc. 002
Otoekuze Inc. 120
Automatic backs seven Inc. 097
Ovuareshingupurodakutsu Inc. 124
Katsu Inc. 088
Car land 119
Kind technostructure Inc. 115
Kakimotoreshingu Inc. 017
Garcon division 114
Can tile office 113
5ZIGEN international Inc. 005
Sun automobile industry Inc. 076
Gee earl Inc. 012
Jieiruto Inc. 013
Gee piece Potts Inc. 125
Jiyaosu Inc. 067
Starting line Inc. 069
Spoon Inc. 044
Possession the Suruga Seiki Inc. 106
Zero sports Inc. 100
Tanabe Inc. 026
Taniguchi Inc. 035
Takeoff Inc. 004
Top line Inc. 110
Trust Inc. 006
Knight sport Inc. 019
Huaburesu Inc. 111
Fujita engineering Inc. 061
Rattan engineering and research industry Inc. 001
Free way Inc. 123
Buritsutsu Inc. 021
Hoshinoinparu Inc. 037
HONDA twin cam Inc. 011
Mainzuueibu Inc. 038
Makishimuwakusu Inc. 045
Pine Shaw Inc. 008
Meiwa Inc. 041
Yajima industry Inc. 091
Yamato Inc. 122 
Lucky automatic Inc. 126
Love lark Inc. 083


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## [email protected] M/S (Feb 16, 2002)

Lee,

depends on what Trust system you can get? 

There are a few that dont flow much BHP , but as I have said before drop the system off behind the cat and run the old girl on the dyno.


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## Chris1983 (Dec 10, 2005)

The Trust Jasma system that was fitted to my car when I bought it had their name pressed into the metal of the middle box and seemed to flow really well....


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## leeroy_25 (Dec 19, 2006)

Thanks guy's I here you Abbey M/S just don't want to miss out on a potential system!
Failing being able to get to the dyno for a couple of weeks. If I drop the catback and drive down the road would my thoughts be correct.. I.e I would notice an increase in boost on the EBC from before and also potentially increased boost response. If it was really restrictive I am sure I would feel the difference!

JASMA listing is very handy I will poke my head under the car tomorrow.

Thank you
Lee


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## dan0h (Jul 26, 2002)

The less of a restriction you have in the exhaust, the faster it'll all spool up, given the cam-timing and other factors are all maintained. But if you bring out some response by freeing the exhaust, you might as well swing the inlet cam a bit to capitalize on some top end increases too


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## [email protected] M/S (Feb 16, 2002)

> I.e I would notice an increase in boost on the EBC from before and also potentially increased boost response. If it was really restrictive I am sure I would feel the difference!


All needs doing on adyno I am afraid . You cant feel things I am afraid.





Welcome back to the GTR world Dan0h.


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## dan0h (Jul 26, 2002)

I quite concur with Abbey M/S sentiments, you'll need a very well calibrated butt-dyno to measure any different in boost threshold response 

Thank you Abbey M/S - Its been a while


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## leeroy_25 (Dec 19, 2006)

Back to the dyno it will be then!!

Lee


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## leeroy_25 (Dec 19, 2006)

Guy's
Had a look at my exhaust tonight. Funnily enough it is a trust cat back system going by the Jasma number on it!
That said the centre box is a big rectangular one and I also noticed the pipe that runs through it does not run straight through.. It enters centrally and exits hard to one side. I gather this is bad for flowing exhaust gas!?
The trust system I am looking at has a nice round centre box with a straight through pipe and looks a bit larger bore. Will see if I can get a number or something off it.

By the way guy's I only mentioned about doing some off dyno tuning if I can get my tuner out on the road with me and a wideband to try and tune it to some normal driving rather than just the full bore runs on the dyno and a bit here and there. Also I gather and have heard from others that what feels good on the dyno can be different to what works well on the road? I imagine lack of airflow in a dyno cell has a lot to do with this?

Cheers
Lee


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