Project 'gozila'...

[Marko R1]

here is the graph - i had the email saved my deleted items, oops

rev limit is set @ 9000rpm

[Sydneykid]

OK, my original post wasn't that far out.

It's in 4th gear (1 to 1) which is around 29 kph per 1000 rpm with a 4.1 diff ratio.

The scale is slightly different as the original post said 0 to 200 kph scale when in fact it's 0 to 220 kph

Maximum torque is at ~138 kph, that's 138 / 29 = 4,750 rpm

Maximum horsepower is at ~180 kph, that's 180 / 29 = 6,250 rpm

The big miss on my behalf was that it has 80 rwkw at 3,000 rpm, 87 kph which is 87 / 29 = 3,000 rpm

As the big man once said "Two out three ain't bad".

Cheers

Gary

[9krpm]

Thanks for the clearer pics Marko.

Here is mine on pump fuel with the Greddy T618Z and power fc before I got a vipec from an authorised dealer in Brisbane

The car was tuned for Boost 98 (10% Ethanol fuel) but had pump 98 fuel at the time of the dyno run so it was a bit down on power/response.

The dyno day was near my house so I just came around to give them some support, it's really a circuit/drag car and not a dyno queen so I wasn't meant to be there anyhow lol

Anyway, if you ignore the actual numbers and just look at the power curve, it looks like your turbo is more responsive but the T618z breath better up top.

Your power curve reminds me of what mine felt like when I had the t517z with the 3L. The torque with the T517z reminds me of a turbo GT2. Sudden thump in the low to midrange and not much at 7-8.5krpm.

Your setup will be quite fast on the circuit.

Dirtgarage, if you have a dyno printout with your HKS GTRS on pump fuel, could you post for some comparision?

I think it would be unfair to post the dyno printout with race fuel because all of the extra response are from timing advance.

[9krpm]

LOL I just had another look at the dyno I just posted

That is one of the worst picture I uploaded on the net lol

I shouln't whinged about your previous dyno pic lol

Sorry, I will try to find a better pic to upload

[Marko R1]

It's in 4th gear (1 to 1) which is around 29 kph per 1000 rpm with a 4.1 diff ratio.

how did you derive 29kph per 1000rpm?

[Swiper the Fox]

Dirtgarage, if you have a dyno printout with your HKS GTRS on pump fuel, could you post for some comparision?

I think it would be unfair to post the dyno printout with race fuel because all of the extra response are from timing advance.

I may upset Steve-o if i put up my graph...ive got a better one to post...its pump...2530's...basic Nissan engine...home built...stock plenum...260 cams...no tricks...at 25psi...Mobil Synergy 8000. Its a good comparo as its same dyno/tuner etc.

ill put it up if Marko wants to see it...its his thread.

9K the one you would like to see is the one from Autosalon with the GT-RS's... it was the day after i ran my engine in...was a basic CRD run-in tune...again pump fuel but this time BP98...only 20psi of boost. Its not really fair to compare a race engine to Marko's...it made 460 something the night before at CRD both Marko's and my curves could be overlayed from CRD's dyno computer and printed off but...even Jim told him not to compare the two when he was getting tuned. Ill see again what Marko says.

Edited July 21, 2009 by DiRTgarage

[Marko R1]

as if i would mind paul

[9krpm]

Sorry it's not the best image but that is all I can do without a working scanner thanks to Window Vista lol

and below is what I meant with the small turbo + 3L RB and the 996 GT2 comparison

Your setup has way more power and will be very good for the circuit......now go and eat some Porschessss

[Swiper the Fox]

as if i would mind paul

here tis...

see two posts below...

you must remember this was run-in @ 20psi only, the torque increased and came in earlier once it was properly tuned with more timing a much less fuel...I don't ask Jim to print off graphs for me as it means 3/5ths of fu(k all when lined up at the track so you will have to put up with the Autosalon ones.

Edited July 21, 2009 by DiRTgarage

[Sydneykid]

how did you derive 29kph per 1000rpm?

I punched it into my gear ratio chart that we use for selecting diff and gearbox ratios for each circuit. The formula is pretty simple as 4th gear is 1 to 1;

Three common tyre sizes for a GTR, 235/45/17 is 512 revolutions per kilometer, 255/40/17 is 515 revolutions per kilometer and 265/35/18 is 512 revolutions per kilometer.

1000 engine revolutions per minute / 4.1 diff ratio = 244 wheel revolutions per minute

244 wheels revolutions per minute x 60 minutes in an hour = 14640 wheel revolutions per hour

14640 wheel revolutions per hour / 515 revolutions per kilometer (for 255/40/17) = 28.4 kph per 1000 engine rpm

14640 wheel revolutions per hour / 512 revolutions per kilometer (for 265/35/18 and 235/45/17) = 28.6 kph per 1000 engine rpm

There is a bit of tyre diameter growth due to centrifigal force, so 29 kph per 1000 engine rpm is close enough for this exercise.

If you have a different sized tyre it can make a difference, obviously, but even a 225/50/16 is 519 revolution per kilomete so not a big deal . The above assumes a half worn tyre, say 5 mm of tread left at 30 psi. A new tyre slightly less rpm per kilometer, a worn out tyre slightly more. Obviously when we are setting up a race car we measure each tyre's circumference as we need to feed that into the data logger.

Check it for yourself, 3,000 rpm is my normal test in 4th gear, so it should be 3 x 29 = 87 kph, plus around 4% for speedo error, so your speedo should show around 90 kph.

Cheers

Gary

[Swiper the Fox]

Edited July 21, 2009 by DiRTgarage

[9krpm]

Paul, is that at 20psi?

Is there any reason why it was dyno in 3rd gear?

Edited July 21, 2009 by 9krpm

[Sydneykid]

got a better one to post...its pump...2530's...basic Nissan engine...home built...stock plenum...260 cams...no tricks...at 25psi...Mobil Synergy 8000. Its a good comparo as its same dyno/tuner etc.

it's interesting though that the 3 litre doesn't make the GT-RS turbos as responsive as people make out.

I've had the opinion for a long time that GT-RS's are OK in single configuration on an RB25 but in twin form they are too laggy for my tastes, even on an RB30. The best RB26 I ever drove had a pair of 2530's on it and it did everything just the way I like it. Paul's remarkable results with 2530's even exceeded my expectations. Next year (I think I said that last year) I am going to try a VQ35 with GT-RS's, maybe the extra 500 cc's will make the difference.

Cheers

Gary

[Swiper the Fox]

Paul, is that at 20psi?

yep...we weren't pushing it as the engine was only fired up 2 days earlier and we were already almost 100kw ahead in the dyno challenge. I didn't see the point of flogging the car on the dyno to please the ricer fans and show car owners set-up next to the dyno cell were whinging about the raw fuel the car was showering them with. The day earlier during the qualifying runs it made 355KW at 11psi...this shocked Todd from Mainline, he looked at me in the car and said..."its only making 11psi mate...is something wrong...i laughed and said not at all, we will come back tomm. and roll 600 with 20psi" (600hp) and we did.

Autosalon don't like exceeding 200km/h on the dyno due to some insurance restraints...every now and then they do. It actually makes no differenceon their dyno whether its 3rd gear or 4th...ill show you something that may dispell another myth if you like. Again if thats ok with you Marko.

Gary would love to see the RS powered VQ...what an engine that would be.

Edited July 21, 2009 by DiRTgarage

[9krpm]

Have you got a power curve with race fuel and full boost then Paul?

Well if it was done in 3rd then you get the impression that it's more responsive at certain speed on the x-axis.

It's like saying your car pull as hard in third gear as Marko in 4th.

I also notice that both your and Mark rpm limits are at 9k rpm and my is only at 8.5k rpm but my dyno speed is a bit higher.

Could someone with more experience explain that? Dyno speedo error?

Edited July 21, 2009 by 9krpm

[Marko R1]

I've had the opinion for a long time that GT-RS's are OK in single configuration on an RB25 but in twin form they are too laggy for my tastes, even on an RB30.

Next year (I think I said that last year) I am going to try a VQ35 with GT-RS's, maybe the extra 500 cc's will make the difference.

Cheers

Gary

all this dyno mumbo means sfa, i honestly think if u went for a drive in my car u would change ur mind

[Marko R1]

...ill show you something that may dispell another myth if you like. Again if thats ok with you Marko.

u have my attention

[Swiper the Fox]

u have my attention

ok 4th gear

the next day we wanted over 500KW so we changed the last two percentages in the AFM table so it made slighty more power in the top end by running slightly leaner...other than that essentially the same tune. If we didn't touch it it would have made the same power as the 4th gear run, although in my opinion the strapping of the car on the 3rd gear run was also better as the car rode up higher on the roller.

these runs are 25psi

it seems pretty much the same result is achieved on a Mainline dyno whether its in 3rd or 4th.

a few years earlier we did back to back runs in 4WD and 2WD...the difference was 2kw. These Mainline units are clever...you cannot fool them...they read very accurately.

Edited July 21, 2009 by DiRTgarage

[9krpm]

u have my attention

My impression is that if rpm is on the x-axis then it doesnt matter what gear it is in.

However if the x-axis is speed then everything that produces "speed" from "rpm" matters (eg gear ratio, diff ratio) and should be adjusted before comparison.

To be honest, I am in the same boat as Marko. I've never driven anything with a rb26 that is as impressive as the RB30.

The worst one I've driven is an rb30 with a pair of TD06. It wanted to do 180 every time it comes on boost.

[9krpm]

Sorry I did not see the second graph when I posted...so I will edit this post.

As you can see there is a subtle difference between the 2 graphs. The power curves looks exactly the same.

However when you analyse the power at specific speed, the dyno run in lower gear always give higher reading.

Dyno operators should print out rpm vs power/torque rather than speed for ease of comparison.

Edited July 21, 2009 by 9krpm