Gtr cam timing for mid range torque

[pnblight]

Hi Guys i have a r33 gtr with milted mods running(424hp at the wheels) i am just installing some tomei poncams (260deg 9.15mm lift) with tomei adjustable cam wheels and belt etc, and i'm wanting to set the cam timing up best for mid range torque. I have read a few article where there are gains to be by fading the cams and was hoping someone might have some advice on where to start ,or it will be a long sesion on the dyno for me and george.

please any advice would be greatly appreciated

[EVL R33]

2 degrees advanced on the Inlet side and 4 degrees retard on the exhaust side is the popular starting point for mid range torque, though that is usually with stock cams but is a good start anyway...

Brett

[R33_KRAZY]

i thought you advance the outlet by a fair bit so you reduce turbo lag an gain some more exaust efficiency... dunno if that is true just wat i been told

[Sydneykid]

My experience has been that Tomei cams are pretty good at zero and zero, so I would start there.

[GTS-t VSPEC]

I agree with SK, alot of the cams I've seen have been best at zero. Start there and if you don't mind paying for the dyno time then adjust it on the dyno to see how you power curve responds to the changes.

[pnblight]

Well guys i just finished the tune and all i can say is its worth spending the time on the dyno as i had hugh increases with cam timing and small fine tuning on fuel and int map

152hp increase

*366hp to 518hp at the rear wheels

*adjustment inlet advanced 10deg (this gave better power in the lower rev range)

exh advanced 8 deg (this gave big increase mainly in upper range)

*added about 1.5 psi boost to get a true 18psi and fined tuned the avcr to come in strong and smooth

*fine tuned int timing and inj maps to get a good fuel/air ratio and torque curve

518hp at the wheels was gain with PFC, AVCR ,700CC SARD Injectors ,260Deg 9.15mm tomei cams with adjustable cam wheels Tomei, rb20 80mm air flow meters, ball bearing garret 320hp turbos, custom exh and inlet piping( i made myself)(the rest all std)

I'm pretty happy as it pulls from about 3500rpm all the way to 7800rpm

cant wait to get it on the track

[Gav]

Nice result

Can you post the dyno graph?

What are the exact specs on the Garrets?

[Sydneykid]

Well guys i just finished the tune and all i can say is its worth spending the time on the dyno as i had hugh increases with cam timing and small fine tuning on fuel and int map  

152hp increase

*366hp to 518hp at the rear wheels

*adjustment inlet advanced 10deg (this gave better power in the lower rev range)

                    exh  advanced 8 deg (this gave big increase mainly in upper range)

*added about 1.5 psi boost to get a true 18psi and fined tuned the avcr to come in strong and smooth

*fine tuned int timing and inj maps to get a good fuel/air ratio and torque curve

518hp at the wheels was gain with PFC, AVCR ,700CC SARD Injectors ,260Deg 9.15mm tomei cams with adjustable cam wheels Tomei, rb20 80mm air flow meters, ball bearing garret 320hp turbos, custom exh and inlet piping( i made myself)(the rest all std)

I'm pretty happy as it pulls from about 3500rpm all the way to 7800rpm

cant wait to get it on the track

Damn good result, everything seems to be lined up and tuned so that the turbos can do their best. I have never seen an RB engine (in fact any engine) respond to advancing the exhaust camshaft, it is always retarding the exhaust timing that gives the best result. The amount (8 degrees) is also extreme, more than I have seen, is it crankshaft degrees or camshaft degrees? Normally it is expressed as crankshaft degrees, with camshaft degrees being double that. Maybe that also explains the large amount of inlet camshaft advance. Might be worthwhile confirming the settings in case you need to duplicate them later on.

Enjoy , looking forward to seeing the dyno graphs.

[EVL R33]

Nice Result congrats, though in your first post you said you already had 424hp at the rears?? Still just under 100hp increase at the wheels is amazing, was the work done down in bunbury or up here in perth??

I've got similar mods to you, including stock internals, I'd think 518 at the rears would be really pushing a standard motor to the limit, anyone else have an opinion???

Cheers

Brett

[GTS-t VSPEC]

A graph of power and torque would be very nice to see:D

[The Alchemist]

I'd say he means camshaft degrees, SK.

good result though, dyno tuning is well worth it eh? I have the same cams in my R32 GTR but with high flowed original Turboes. I've been playing around on the dyno and got 185rwkw at 6200rpm, stopped there as it was way too rich , like 11:1 and we run out of time. We did however, get the boost controller sorted out which gave me a 20% increase in rwkw at 3800rpm which was well worth on the road!

Well done.

Mike in NZ

[CerealKiller]

that's a huge increase from cams and a dyno tune.

EVL R33 - I think at 500bhp his front mount is maxing out (I've heard many a time that they're good for 300kw). 18psi isn't that much for the GTR cooler or is it?

[The Alchemist]

its all to do with the turbo outlet temps and the turboes efficiency at different boost levels nothing really to do with the intercooler unless of course you push the turbo boost to high and out of its efficiency range.

[pnblight]

ha guys ,i will try and get to a scranner asap as i dont have one

with the deg the tomei pulley said deg of crankshaft (we exspected to retard exhaust as well but it lost power quick ,i even double checked timing to make sure all was well)

ok the horse power i quoted 424hp was at hyperdrive when i ran it on the local adrenalines dyno it went 379hp (you know the story different dyno etc) so after fitting the cams ,cam wheels and new tomei belt ,n1 water pump it went 366hp or some thing and thats where we start the tune and ended at 518hp so i have tried to keep track of progress as best as posible

another point of interest you might be interested in was we turn the boost right down to about .8 bar and still maked well over 400hp at the wheels

[pnblight]

and the other thing we were run regular 500hp flat but after lengthly dyno test had got quick hot so we let it cool down for 15 mins or so and thats when we got the 518hp so my next points of call will be lagging of pipng ,cold intake box , turbo lagging etc maybe even bigger intercooler

[pnblight]

Dyno Chart

[Emre]

Did your dyno operator get the AFR probe and temperature probe mixed up...?

388 rwkw on 18 psi is really impressive as well, we have a lot to learn from WA.

[Sydneykid]

Did your dyno operator get the AFR probe and temperature probe mixed up...?

388 rwkw on 18 psi is really impressive as well, we have a lot to learn from WA.

Emre, check out the AT= 25 and IT = 82. :headspin:

[meshmesh]

WWWOW... 388Kw at the rears on stock internals, and only pushing 18psi on pump fuel... Is that right? I couldn't believe it when I read this thread, I thought that could only happen in WA, and then I saw you were from WA, and I wasn't supprised... Well Done!

Just one thing, Stacey who has the R32 with forged Internals, full HKS Kit GT2530's, dumps manifolds etc etc.. makes 390kw at 25psi on pump fuel ~I think... I mean your result is definately impressive but nonetheless not suprising from WA those tuners have magic up there sleeves with dyno tuning GTR especially with RB20 AFM I never thought they were capable of that sort of resolution.. Obviously Stacey's R32 GTR has some big problems when comes to tuning

[Emre]

Emre, check out the AT= 25 and IT = 82.

I noticed that SK, hence my comment :

Did your dyno operator get the AFR probe and temperature probe mixed up...?

Maybe he took his intercooler out for weight saving.