Rb30/26 Final Tune Feedback

[leeroy_25]

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 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 that was it sometimes stalled when lifting off from high rpm and putting it in neutral. There is a thread about that here: http://www.skylinesaustralia.com/forums/topic/369343-q45-maf-pointer/page__p__5891148__fromsearch__1#entry5891148

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! 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

[Dale FZ1]

Given the boost level and rpm cap, the results look pretty good to me. Quite strong mid range stick.

What is your exhaust manifold setup like, and how quiet/restrictive is the exhaust system? Be worth looking at them after checking your wastegate and boost controller. My guess is that if you get it to hold boost and run it to 7000 you'll hit the target.

[KiwiRS4T]

More boost! Nothing wrong with Holsets but don't know the capacity of yours. With a GT35/40 you could expect 375kw at 1.5 bar. Have you got a 3in exhaust or better? Need a better fmic? You need to measure fuel pressure to see if your system is keeping up. Does it lean out at the top? Pump wired for full voltage? Are you using a PFC?

My guess is you need more boost but I don't know how big your turbo is... and get a higher value spring for your wastegate.

[leeroy_25]

Cheers for the feedback guy's that makes me feel better!

For some more info.. The Holset is an HX40 with 19cm housing so should be no problem for it.. if anything it is a touch on the large side!

The manifold is XS Power tubular stainless top mount type with T4 flange. I have modified it with a large wastegate section to fit the 60mm gate and also beefed it up to hopefully stop it cracking at the joints! I did also tidy up inside as much as I could. A guy I spoke to actually implied the pipe diamter was a bit too large for optimal boost anyway?

The rest of the system is 3.25" inch all the way back.. But I have to say other than the screamer pipe it is very quiet? I thought maybe due to the large turbo? I wil have yo check the make of the back box.

I am running OEM intercooler.. I thought they are good for 600bhp?

Also OEM FPR.. which I thought the same?? Another possibilty with the fueling is there was some kind of regulator or over pressure valve in the tank after the pump.. (R33 V-spec). Should I have taken this out as I left it in not being too sure of it's function?

As you can see from the AFR's on the print out the car is no going too lean.. Still that is not to say the pump is struggling on one run and then keep up on the next giving extra line pressure? Not sure if that would account for the changes?

I certainly don't want to run more boost than 1.2bar on my stock bottom end as I am kean that it be a good reliable daily driver! So hopefully I can make my goal by sorting out these few issues?

Barring in mind I started out with 370rwhp on 0.8 bar and a rich map I also wondered if maybe the cam timing is restricting the high boost from being effective? I thought the boost increase would give more gain than that in itself?

Having said that I did time the cams to give me optimum boost response and low-mid power which in reality is all you get to use 90% of the time!

Please keep the feedback and thoughts coming.

Thank you

Lee

[KiwiRS4T]

The amount of boost is not relevant to the life or well being of the bottom end. Its all in the tune.

[NYTSKY]

For the boost level it looks pretty good.

Bigger injectors and E85 you will crack 500rwhp+ easy.

[leeroy_25]

Thanks guy's E85?! I am running this as a road car so sticking to pump gas only I am afraid 99 octane! Injector wise I am getting 80% duty at the mo so still a bit of room there! IIRC E85 requires bigger injectors anyway so I assume that is why you mention that?

Remember the dyno rpm scale is out so where it shows peak at around say 6250 it is actually 6500rpm real world.. Running it past that at present the power dips off. I could probably adjust the cams back a bit to up the peak power but then I will lose it in the low-mid range where it matters. Would be interested to see how that compares to other dyno print-outs at the mid range.

KiwiRS4T.. Surely boost will kill a bottom end if you go too high? sure I understand it is all in the tune to an extent but surely more boost is physically more load on the pistons and rods and will bend or crack something eventually no matter how good the tune?

Oh so the increase I have from 0.8 bar 370rwhp (rich map) to 1.1bar 440rwhp sounds about right? I say 1.1bar as that is where the boost is at peak power.

On a slight side note can someone tell me if when I upgrade my in tank pump should have removed the in-line pressure regulator thing that connects above the pump in tank on the R33 GTR?? Not sure if that buggers up the flow on a larger pump? Also while on fuelling can you confirm if I am right in thinking the OEM FPR is good for 600bhp? i.e more than I am looking at? I just want to try and figure out the reason for the random AFR changes on the runs. It happened more than once. Could it be O2 sensors messing around?

Thank you

Lee

[KiwiRS4T]

KiwiRS4T.. Surely boost will kill a bottom end if you go too high? sure I understand it is all in the tune to an extent but surely more boost is physically more load on the pistons and rods and will bend or crack something eventually no matter how good the tune?

I used to think that until someone pointed out the obvious which is that the load put on the pistons etc by the combustion process is many, many times 1 or 2 bar which is why other factors such as fuelling, timing, exhaust etc are all much more important to the life of your engine than the difference bewteen 1.2 or 1.5 bar of boost. But power is about flow and if you haven't got enough then your power will be limited (not saying you haven't got enough power but if you want more I suspect you will have to turn up the turbo a bit!).

[DVS JEZ]

1500psi combustion pressure. So adding a couple of psi wont smash pistons.

Detonation can spike the combuation pressures too 5000psi which can smash pistons, bend rods etc

[leeroy_25]

Okay.. I guess that is a fair point.. but can I offer a counter.. Why can I not then run 2 or 3bar boost? I totally see where you are coming from but then there must be other factors as well otherwise no one would be running forged bottom ends and everyone would be on crazy levels of boost?

I will see what happens when I can get it to hold 1.2bar boost properly and stop the fuelling problem.. I could tweak the cams back the other way to get more top end I guess but then I am just chasing big numbers and sacrificing where it counts?

Thanks again

Lee

[R31Nismoid]

Does anyone else think it's a bit laggy for a 3ltr ^ 1.2bar/370rwkw? A GT35 would be doing similar and coming on much sooner.

Especially with a 4000-6500rpm power band

Exhaust might be an issue. Fuel reg isnt an issue, cooler isnt an issue.

Boost drop will be wastegate related. If you wanna run 18psi - then get the spring combo closer to target boost and that problem will fix itself up much easier. Otherwise the EBC will never hold having to bleed that much off, you'll always get gate creep.

[KiwiRS4T]

Sorry didn't read down as far as the 500+ hp. Power's not too bad at all but still if you want more try 1.5 bar.

Why can't you run 2 or three bar? Well you could if the turbo could make it (some of the drift guys are running that much boost) but you can only use so much flow - say you ran three bar (and you could get the flow through the i/c and head) and had the fuelling etc to go with it you would definitely break something! but more likely the head and valves wouldn't handle it and you would need a huge exhaust to flow that much.

[leeroy_25]

Thanks for the replies again guy's..

So Just to clarify as I think maybe some people have read the wrong graphs or lines of text.. At the mo I am at 437rwhp at around 6500rpm and 1.1bar (I say 1.1bar because it is not holding 1.2 yet! max torque at the wheels is 410ftlbs at 4500rpm ish. The 518bhp figure is estimate flywheel.. which I guess in turn gives around 460ftlbs at the flywheel?

So, R31Nismoid.. you say laggy.. I can see your point looking at the plain numbers like that but it sure doesn't feel laggy! I thought the idea of a big engine was so you don't need to rely on the turbo so much! If it came on too much sooner I would go through tyres like no tomorrow! It spins up in third easy as it is! I have spoken to other guy's with similar rpm limit goals. ie 7000rpm and they are seeing similar boost response on Garrets and so on? I was hoping to get a bit in before maybe around 3500rpm would be nice. When you say a GT35 comes in a lot sooner when roughly?

I would ideally have gone for a exhaust housing smaller but I could not find one at the time so had to take a flyer on this one! My build is on a very tight budget! and as they say beggars cannot be choosers!

KiwiRS4T - that makes some sense also.. I think the Holset can run 3bar all day! But I won't try!! I do see how the other restrictions then come in to play.

So, guy's I am really keen to get some thoughts on the reason the AFR's changed from one run to another like that with only a top end lean adjustment resulting in a richer map. It seemed to possibly get richer when doing runs in quick succession.. so maybe heat somewhere? air intake temps? I noticed on the road today cruising at around 50mph the intake temp is hitting around 40-42 degs? with a some speed up it drops to the high 30's.. Not sure if that is an issue.. undoubtedly it was probably hotter on the dyno with lack of air circulation. O2 sensors? I did wonder whether the pump was struggling and keeping up one run then not so well the next but as I said the injector duty seemed to be unaffected which I would have expected if the pump was an issue? The only other thing is line pressure if the in tank relief valve or what ever it is is causing a problem? I am also changing the filter just in case.

Boost wise I will pre-load the spring and sort that out. I wanted to run a low setting or 0.8 bar really but I guess I can go up a bit on that and take the spring load as close to that as possible

Exhaust wise does quiet always mean restrictive? I think the back box just bolts on at the tail If so I could run it on the dyno with the box off and see if that makes any difference?

Please do keep the thoughts and ideas coming.. it is all helpful.

Thank you

Lee

[TiTAN]

Thanks for the replies again guy's..

So Just to clarify as I think maybe some people have read the wrong graphs or lines of text.. At the mo I am at 437rwhp at around 6500rpm and 1.1bar (I say 1.1bar because it is not holding 1.2 yet! max torque at the wheels is 410ftlbs at 4500rpm ish. The 518bhp figure is estimate flywheel.. which I guess in turn gives around 460ftlbs at the flywheel?

So, R31Nismoid.. you say laggy.. I can see your point looking at the plain numbers like that but it sure doesn't feel laggy! I thought the idea of a big engine was so you don't need to rely on the turbo so much! If it came on too much sooner I would go through tyres like no tomorrow! It spins up in third easy as it is! I have spoken to other guy's with similar rpm limit goals. ie 7000rpm and they are seeing similar boost response on Garrets and so on? I was hoping to get a bit in before maybe around 3500rpm would be nice. When you say a GT35 comes in a lot sooner when roughly?

I would ideally have gone for a exhaust housing smaller but I could not find one at the time so had to take a flyer on this one! My build is on a very tight budget! and as they say beggars cannot be choosers!

KiwiRS4T - that makes some sense also.. I think the Holset can run 3bar all day! But I won't try!! I do see how the other restrictions then come in to play.

So, guy's I am really keen to get some thoughts on the reason the AFR's changed from one run to another like that with only a top end lean adjustment resulting in a richer map. It seemed to possibly get richer when doing runs in quick succession.. so maybe heat somewhere? air intake temps? I noticed on the road today cruising at around 50mph the intake temp is hitting around 40-42 degs? with a some speed up it drops to the high 30's.. Not sure if that is an issue.. undoubtedly it was probably hotter on the dyno with lack of air circulation. O2 sensors? I did wonder whether the pump was struggling and keeping up one run then not so well the next but as I said the injector duty seemed to be unaffected which I would have expected if the pump was an issue? The only other thing is line pressure if the in tank relief valve or what ever it is is causing a problem? I am also changing the filter just in case.

Boost wise I will pre-load the spring and sort that out. I wanted to run a low setting or 0.8 bar really but I guess I can go up a bit on that and take the spring load as close to that as possible

Exhaust wise does quiet always mean restrictive? I think the back box just bolts on at the tail If so I could run it on the dyno with the box off and see if that makes any difference?

Please do keep the thoughts and ideas coming.. it is all helpful.

Thank you

Lee

my GT35 0.82 rear is making ~20 psi just after 3500rpm.

your HX40 is a diesel turbo off a big truck and 400hp is lower end HX35 power you need to shove some boost into it.

[DVS JEZ]

More boost =more heat = more detonation prone

98octane fuel will pre- ignite in the cylinder with too much heat.

So u are right in saying about 2-3bar of boost. But we arent talking those crazy numbers. 2-3psi yep more so.

The 2 runs going richer could very well be an air intake correction or a water temp correction richening the mixture.

What ecu?.

What ecu?

[leeroy_25]

I am running a Power FC ECU.. standard MAF type.

I am aware the turbo comes from a large diesel motor! I think for the engine CC the HX40 is the right compressor housing.. I think the HX35 would not cope top end. I think it is a case of needing a 16cm turbine housing over the 19cm I currently have ideally.

If I find one great but for now I have what I have!

Thank you

Lee

[leeroy_25]

I missed some points to reply to earlier.. Water temp and oil temp wise I know there is no problem! That is actually the first thing my tuner asked.. is the oil cooler getting hot? It was perfectly fine and the water temp and oil temp struggle to reach 80degs!

However air temp is a different story. I did not think to check that at the time and I am not sure if my tuner did. Just checking the Power FC settings you start getting air temp correction after 40degs. I know from driving my car yesterday and checking that is reaches 40-42deg in generally slow moving traffic so stuck on a dyno with limited airflow I guess it is a strong possibility it would go higher? I reckon it would only need 50degs to get the sort of correction I am seeing on the printout. And the fact it seems over the entire map kind of fits? but then that said .. Will the correction change the exhaust gas AFR like this as I would assume the correction is to try and keep the burn the same and prevent knock? warm air gives less effective combustion right? So actually if you add fuel to make it safer??! then you would get richer exhaust readings for sure?! Have I got that about right? Not sure how the more fuel for less burn works though?

What you all think.. have I maybe cracked it!? Wonder if I can get a logged max air temp from those dyno runs to check?

Cheers

Lee

[KiwiRS4T]

Dynos are great for quickly seeing the results of changes you are making but there is a good case for fine tuning your tune on the road if your tuner has the gear and the inclination. Those who have done it say that real life road testing can give results different from those on the dyno. If that's not possible and you have datalogging capability at least you could do some comparisons with the results you are getting on the dyno. I would guess most dyno cells would get pretty warm.

[Cubes]

IMO don't mess with preload. Get the wastegate spring as close to the boost you want to run and tweak the boost response with the EBC. I stuffed around for a long time, it just doesn't work if your making decent power. I don't think of EBC's as a way to control final boost but more so a way to improve boost response.

Lean out the AFR's to high 11's - 12:1 flat and get that boost up to 18-20psi.

Whats the ramp rate and lift on those cams? From my experience you really need to be looking at 10-10.5mm lift to achieve around 390rwkw with <20psi with a GT35R .82.

HX turbo's are best at higher boost levels. Get that wastegate spring sorted and providing seat pressure is fine you'll find it will make good power if the tuner has half an idea.

[leeroy_25]

Cheers Cubes.. I know ideally Holsets for more efficiently at higher boost. but this is my first build with all stock internals so I don't want to push my luck! The HKS Step1 cams I think are 9.1mm lift off the top of my head. not sure on the other specs.

Do I really need a spring?! Why does pre-load not work? If I want to run 11-12psi low boost I don't think the spring is more than a few psi off? I will check though.

I want it so hold good solid 18psi though.. maybe 19 for the most!

AFR wise we were aiming for the mid 11's as it happens.. Just the sudden change messed us up at the end of the day and then we ran out of time. Hopefully I have the answer to that but wont know until I go to the dyno again now! If air temp correction is not the answer then it will be a wasted trip!

While we are talking AFR's and boost.. What is a good sensible knock value to be hitting? i.e if I am hitting 40-41 every now and then am I safe?? Generally a heavy squirt gets you in the mid to high 30's?? Obviously the lower the better but what is considered dangerous for my stock internals?

Thank you

Lee