Gt2860r -7 Or -5 Response

[a20089]

Thanks for the advice R31Nismoid. I didn't get a printout of the AFR graph.. I'll go and have a chat to my tuner this wkend...

I was reading this thread http://www.skylinesaustralia.com/forums/Rb....html&st=80 adn noticed that a few of the guys are getting the same figures I'm getting.

Here is a post from 700HP-GTR33 who has similar mods to me:

and a20089:

Power 266.5 @ 18PSI on new "fuel efficent" tune (low reading dyno)

Power 265 @ 17.5-18 PSI on full fuel (Croydon dyno)

Power 244.1 @ 15PSI on full fuel (Croydon dyno)

Mods

K&N panel Airfilter

Full exhust with 5" CAT

Pair Garrett 2860-5 turbo's

Apexi Power FC

Blitz ID-3 boost controller

Jun Cam gears

Stainless dumps

Thats because I've got stock injectors, stock AFM's and stock fuel pump. I'm maxing out everything listed.

at 20PSI I would be expecting 330-350rwkw

[R33GTRKid]

tutt tutt boys read carefully, he has got 291.1 AWKW which would be closer to 320-330 RWKW..... so seems not too bad although I still think at 20psi those -5's should be pushing a little more, seems the tuner has been a bit lazy and opted to up the boost instead of timing/fuel...?

[ISC-Performance]

before I bought my turbo's I was weighing up between these 2 for weeks! Ended up going for the -7 and I'am extremely happy i did. About as responsive as stock turbo's and making 315rwkw on 19psi, If you get the -5 you really need cams etc to get the most out of them and loose some of the lag.

Ryan

[R31Nismoid]

tutt tutt boys read carefully, he has got 291.1 AWKW which would be closer to 320-330 RWKW..... so seems not too bad although I still think at 20psi those -5's should be pushing a little more, seems the tuner has been a bit lazy and opted to up the boost instead of timing/fuel...?

tutt tutt indeed.

I hate being a broken record... but... it's been proven a number of times AWKW/RWKW is near enough to the same. 10rwkw if you want to stretch.

Least of all a 40rwkw loss, totally incorrect.

This has been proven by 2 or 3 users now there is bugger all difference, have a search by DirtGarage and a few others who've tested, posted and shown there to be stuff all difference

GTR's are not fulltime 4WD far from it, its not the same loss as you'd expect from something like an EVO or WRX where you would say 330rwkw would be 290awkw... GTR's & 4WD are a different kettle of fish im afraid.

Its more of a noticeable loss when you have a modified transfer case that transfers the power more so then you could say so, but we are talking stock transfer cases here, so next to no loss.

[some_cs_student]

As above, per Ash's post, that's been proven several times

Some results were a 1KW difference.

Could the lower than normal power figure be because of maxxing out the AFM's or something else that is been maxxed out?

[700HP-GTR33]

In an ideal World..if we all got together and got on the same dyno on the same day.....most of these

so called tuners..upping the figures to make the clients feel good about the money they fork out

for the work that they perform........might just have to eat their word.

We have more than one case...Not just Blitz_R33 but myself and others with the same figures using the same turbo's on the RB26 Turbo upgrade sticky....read and you will see...the workshops that perform the -7 or -9 upgrade that swear by stock cams...keep produce lovely figures..with little or no deviation with the AFR or the Kw delivery..its like the graph was smoothed out to make an impression.The funny thing is...most of these -7 and -9 upgrades produce more power than most of the -5's..lol

The AfR's are the best...straight line...lol..all the way..full dyno run..and its perfect mate...

The other thing here is Torque is never mentioned..its all about kw....whats with that?

There are many tricks in this game...and if you think what a few say here that have been to these tuners.

The topic discussed on the subject of rwd..vs 4wd is a little fuzzy though.

Most tuners say there is a difference of 20 to 25%..some say they have tested it and have found nothing.

Is this another type of myth.....lol

Tuners are here to protect their secrets..but also they are here to make money..so producing better figures for their clients

also brings in more clientel.

Before you all fry me again because I am telling the truth..read the RB26 upgrade and compare the graphs and the figures.

So if anybody here believes the -5's are slower than the -7's and 9's they need to really look hard at the evidence.

The real variety.

Or better still have SAU organize a dyno day...........I have always said this may just be the answer to this topic.

Everyone on the same boost..say 1 bar

My 2c again...

[R31Nismoid]

look at the paperwork and the specs behind the -5's, similar to that of 2530s...

They will ALWAYS be slower on boost/response because they have larger wheels. Simple logic and physics cannot be argued upon. You cannot make a larger turbo, be faster/more responsive than a smaller one all things being equal.

I'll go and get a 6+ -5 graphs this weekend if you want, all of them over 350rwkw. Plenty have done it, most just CBF'd posting and dont even have SAU accounts because they are too busy racing and couldnt care less. They have the power, they have the times, thats all that matters

Its simple. The -5s have a larger front and rear, the -7/-9 smaller on a scale.

The -7s will make 330rwkw max, -5s can do over 400rwkw on a proper motor (same deal as 2530)

Why have a dyno day with everyone on 1bar? Pointless because different turbos have (surprise surprise) different efficiency ranges.

So everyone running the same boost proves nothing other than some turbos are more efficient at that level... which is no surprise nor secret to people with half an idea about turbocharging.

[700HP-GTR33]

OK...let me explain it again.

There were 4 different Turbo combinations that Garrett made.

The -7(N1),-9(SS) were close as far as Performance.these were the N1 and SS equivalents.

Both these Turbo's have a very similar housing size as Stock and are rated to be able to

support 300 and 320hp respectively.

The factory stock turbo's I recall were rated either to 260 or 280 each.But don't quote me on this.

Now the -5(GT2530) and -10(GT-RS) have bigger housing and are able to support 350 and 400hp respectively each.

In no way unless you want giant lag should you use -10.(GT-RS).......unless you have a built motor with high lift cams dialed in

buy a good tuner. Even then you will see power higher in to the rev range that makes driving around town stupid.

These are only good for drag and whiplash when they start to spool at 5000RPM.

Now most people here swear by the SS or N1...both of which are great for low power delivery and great therefore for street.

Responsive and a good package.......no mods needed slap them in and presto.....

OK......If you want some serious usable power mid to high range the -5's are good.

But I only suggest -5's if you continplate upgrading Computer,Cams,Dumps,Injectors at a latter stage

or if you are thinking it will be a work in progress.

The other option is to go 1 Single and be done with it...although this can be a lot more costly.

I am in no way slandering or stating one is better than the other....as you see in my post above.

I am also not arguing the dynamics of the different turbo's and the way they reach efficiency.

You cannot except figures on the turbo upgrade sticky to be accurate 100% as fiddling the Dyno can be done.

Just stating the obvious...and if people here can't see that...bad luck to them.

I run my car every day...and really am not interested in Dyno results..if I plant my foot..I am going to get busted

no matter how much kw's I have.

If I can get to a 1/4 mile meeting and run a few 11's......I am very happy.

I did once care about dyno results..now I really could not be bothered with...

mine has this much..and yours has this much...so I have a better tuner and better motor

.

Dyno results mean nothing on the road...you will only ever see 7000RPM if you plant it.

Just an indication.....Five speed GTR...60 first...130 second....190....third.....230 fourth...250+ fifth.

This is approximate...most of you all know this...don't take much to loose your license.....

-7's,-9's,-5's or -10's aren't going to make any difference..

Stop arguing about it.....just enjoy your rides...we would have a lot more fun then...

[Blitz_R33]

Well said 700HP-GTR33... In the real world, all dynos would give the same reading... but at the end of the day we all know a dyno is a tool to tune cars... Like I said.. I did not want my tuner to tune my car to be a dyno-queen....

I drove the car home from work this arvo, got to a set of lights, saw that no cars were around, so I decided to put my foot down and launch it. OMFG I think I felt a turtle come otu of my butt. All 4 wheels skidded in first, then the car went a little sideways in 2nd before the altessa kicked in and straightened the car... I didnt really feel any lag from the turbos just instand power at all 4 wheels. This was all at the boost setting os 14.9psi... Tomorrow I'll try it set at 20psi.

If all goes well, my brake pads arrive by Friday. I can then fit the new pads n rotors to the car on Saturday, ready for Willowbank Saturday arvo so I can post my 1/4mile time.

PS. I don't know if you know Godzilla Motorsports (QLD) signature R32 GTR Drag Car? The same tuner that tuned that car, tuned mine. I'm sure he knows what he is doing

Edited October 22, 2008 by Blitz_R33

[R33GTRKid]

R31nismoid - I stand corrected!@

touche my man

[Rowdyr32]

GTR's are not fulltime 4WD far from it, its not the same loss as you'd expect from something like an EVO or WRX where you would say 330rwkw would be 290awkw... GTR's & 4WD are a different kettle of fish im afraid.

Its more of a noticeable loss when you have a modified transfer case that transfers the power more so then you could say so, but we are talking stock transfer cases here, so next to no loss.

What is the difference between a modified transfer case and a std one on a 4wd dyno. The torque split will read 50/50 if the case is in good condition if the transfer cases are locked. No slipping. A modified transfer case doesn't effect the torque split of a gtr on a dyno. How can it? When its locked its locked. Why is there such a big difference between a normal 4wd compared to a gtr as they just don't have the clutch packs in the transfer case. I don't see the diffence on a 4wd dyno?

As for turbos I had 32 N1's on my car spiking to 20 psi and back to 18 to make 290rwkw at 100% inj duty. I now have -5's which will run the inj up to 98% at 14psi on the same tune. Haven/t been on the dyno yet but it feels similar and I haven't had the car retuned or cams dialed in yet. I don't see the need for cams as a lot of cars in vic are making good power and response out of std cams. A lot of guys went back to std cams to make more in the mid range and the same up top if what I have been told was true.

Boost/Rpm/Power. So many opinion I thought I'd add my 2 cents.

I like the idea or running a bigger turbo to to run my engine with less boost for the same given power expecially for track which is less strain with cooler inlet temps so more more ignition timing can be run and only to sacrific a little lag if any say max 500rpm atm. If you drive a gtr hard if shouldn't drop off boost with either -5 or -7 unless your slowing to 20kmh and then re-accel where you can just clutch it up if needed. Anything over 270rwkw in any car on the street your going to have trouble powering out of corners and if you are a drag fan who really cares about lag at all as I can spin 4x265 street tyres straight off the line with -5's and 280rwkwish. If 300 or 500rpm is going to rock some of your boats you must be race car drivers racing for money to spend money on your cars to try and get a few hundred rpm less lag. Does it really matter that much for something that just gets driven on the street or club days for fun. With some time tuning down low down rpm driving shouldn't be an issue on or off the street.

My next mod is 4.4 diff gear to myltiply my torque by .236 = Less lag and more torque. Win Win situation

You all talk about what rpm does it hit full boost by but your all running different boost pressures at different altitudes with different humidity and different temperatures with different diff ratios and different tyre sizes and different fuels with different engine compressions etc so it all means sweet f/a if your going to argue the fact of 10 or 20 kw. We had a dead accurate dyno at work doing gas turbine aircraft engines that was correlated with an engine from America every two years with calibration every 3 months (test every pressure sensor within 2%and the same with temp sensors plus the load meter) All up about 35 sensors. It corrected every run pack to a standard day. We were continiuosly maintaining the dyno room to maintain this accuracy and it was a direct drive.

As a lot of you have posted:

Add all the variables of a rolling dyno and they are only really good as a tuning tool for that car on that day.

If you really want to compare boost response of turbos the only way you could do it properly is to put an engine on a engine dyno and tune its turbo to its peak efficiency and the on the same motor try the next turbos setup and do the same collecting trend data on the engine to measure its condition after each turbo swap.

[Kranker]

My next mod is 4.4 diff gear to myltiply my torque by .236 = Less lag and more torque

you cant multiply torque, you can multiply your tractive effort, by changine ur final drive... too many people confuse these two things

The tractive effort is torque multiplied by the total ratio of power train (gearbox, diff etc.) all divided by the rolling radius of the tyres.

sorry for being a fussy prick (hey, im an auto eng student), but people keep saying that their car makes thousands of Nm, when really its tractive effort (which is in Newtons)

sorry, back on topic

[GTR1993]

the only way im aware you will multiply torque is with an auto trans before the converter is locked.

Edited October 24, 2008 by GTR1993

[djr81]

Stop smoking crack you two.

Any gear box will multiply torque when it is not in fourth, ie 1:1 ratio. That is what its job is. You cannot multiply power, however. Power = torque x rpm. So relative to the input side of the gearbox on the output side you get more torque for less speed. Same power minus some small losses.

A lower diff ratio (or gear) allows the engine to make more power (Up to its maximum putput after which it obviously starts declining) and therefore get it to the rear wheels.

IMHO, put simplistically the test for a turbo Rb26 should be two things:

How much peak rwhp.

How much rwhp is generated at 4000rpm.

As for using a bigger turbo for lower output temps that is doing the right thing via the wrong mechanism. To lower the compressor outlet temps you should use a more efficient turbo which is not necessarilly the same as a bigger one. Compare, for example the "Group A" compressor map to a dash 5.

[Kranker]

ive been trying to quit for ages, that shit is addictive

[GTR1993]

lol i just laid the pipe down, so what was that about multiply torque again lol and to think i done all this at uni

i like power= torque x angular velocity because then u dont need to divide by a constant to get correct number etc.

Cheers

Edited October 24, 2008 by GTR1993

[R31Nismoid]

What is the difference between a modified transfer case and a std one on a 4wd dyno. The torque split will read 50/50 if the case is in good condition if the transfer cases are locked. No slipping. A modified transfer case doesn't effect the torque split of a gtr on a dyno. How can it? When its locked its locked. Why is there such a big difference between a normal 4wd compared to a gtr as they just don't have the clutch packs in the transfer case. I don't see the diffence on a 4wd dyno?

Its not 50/50!!! Its only transferring when it needs to, thats the whole issue.

On the road, with a massive launch ye its shifting as much as it can... but on a dyno thats simple not the case

if people have tested it, proved there to be bugger all difference, then what is left?

Theory only goes so far sometimes

[some_cs_student]

What is the difference between a modified transfer case and a std one on a 4wd dyno. The torque split will read 50/50 if the case is in good condition if the transfer cases are locked. No slipping. A modified transfer case doesn't effect the torque split of a gtr on a dyno. How can it?

As per Ash's post, its not going to be providing 50% to the front wheels.

However, since a modified transfer case will have a slightly more / different clutch pack, it will transfer more to the front wheels, but in the end it won't make much difference on a dyno.

Not sure what your getting at when you say "locked" its a transfer case not a diff, it doesn't lock (from my limited knowledge of GTR transfer cases )

Please tell me if anyone disagrees with the above, still learning about Skylines

[Rowdyr32]

Ash I know how a 4wd system works on a gtr. I'm only talking about a 4wd dyno. You have to remember though that the front wheels are still turning the front axles, diff and drive shaft and one gear in the transfer case and a chain even when the transfer case isn't transfering any torque. The transfer case is also electronically operated so there is no power loss from engine driven pumps.

On a 4wd dyno the transfer case locks due to the rear wheels spining. A piston compresses the clutch pack. I'm only talking on a 4wd dyno. If the clutch's are compressed 100% they are locked up. 50% of the drive goes to the front and 50% to the rears on a 4wd dyno.

"Its not 50/50!!! Its only transferring when it needs to, thats the whole issue.

On the road, with a massive launch ye its shifting as much as it can... but on a dyno thats simple not the case"

It is the case Ash. It doesn't have to be a massive launch at all. All that has to happen is the rear wheels spin a little. I guess gtr's go 50/50 on a 4wd dyno as there is no foward movement detected by the g sensors so it gives all the drive it can to all wheels.

Read the trouque split of a gtr on a 4wd dyno and it will read 50/50 on a full power run! This is how you check the condition of a transfer case. If it doesn't read 50/50 it is slipping. There is no way at all that a modified transfer case can change the torque split when its locked up.

Some cs student you don't know what your talking about do you. Whats that. No No you don't. I don't get how some of you don't get it. How can a transfer case tranfer more than 50% of the torque to the front wheels when it is the same final drive ratio as the rear and the rear drive line is fixed to the engine when in gear. It can't. Never will.

Read this people: This is what I know.

Modified transfer cases only effect the speed in how fast a transfer case locks up as the piston doesn't have to move as far to start compressing the clutch. It does the same as tsc. It cannot effect the amount of front torque when the clutch packs are 100% compressed/locked.

Cheers Djr81. As for the diff ratio and some of you so called students in engineering. Keep studying if you think a changing in gear ratio won't effect torque on any parts thoughout the drive line. The explination of the diff ratio was an example of how to get more torque easily. I worked in Borg Warners research and development centre (DSI) as the main dyno operator running 4 dyno dynamics dyno's to test prototype automatic transmissions. So if some of you want to argue the point of gear ratios and torque go for it and I never went to uni.

[GTR1993]

Just went and had a look at my torque split gauge, its not in percentage, its in kg/m, so does that mean its maximum lock is 50 kg/m not a full 50% split....

Edited October 25, 2008 by GTR1993