Cam selection

[Galantman]

hey guys, I've got myself pretty much sorted for Tunes and comfort in my vr4 now. so time to move to the go fasts

from the old '74 galant 2.6 astron days. i had what was refereed to as a gt30/40 with .63 turbine housing. and i was really happy with its boost response and go fasts

compressor wheel is 82/62mm and turbine is 56mm exducer with .63 housing. goign over the current garrett catalog it seems to be very similar to a gt35/82R

so what im wondering is seeing as i need to do a rebuild anyway ( proper VR4 Head is not on the car currently due to cam tunnel damage). What cams should i be looking at to complement the turbo i have currently just sitting around doing bugger all
will also be needing exhaust manifold and external gate to suit ( to hard to get parts for the sigma 32mm one to continue its life span), i was thinking 6boost manifold and whatever gate suits.

throw the ideas at me, and yes i will be going aftermarket ECU to suit also ( suggestions appreciated for this also)

car will be basically a daily driver, but i really do like the go fasts and enjoyment of drags/ tracks days when i get the chance to have fun!

 

[ONPSI]

+1 for 6boost exhaust manifold, I wouldn't run any bigger then 272's for street use.
That 35r is going to spool late on a 2L unless you were to stroke it. From what I have seen before you'll be pushing into 5k+ rpm for full spool

 

[Galantman]

+1 for 6boost exhaust manifold, I wouldn't run any bigger then 272's for street use.
That 35r is going to spool late on a 2L unless you were to stroke it. From what I have seen before you'll be pushing into 5k+ rpm for full spool

late boost isnt a bad thing, hell of a lot less likely to get in trouble around town if being a fool. which is what i liked about the old setup. enough torque to still put around without being frustrated. If i don't lose much if anything of the current low down performance i'll be pretty happy.

 

[EVO-00X]

My 2L VR4 engine (P&P'd with 1mm o'size I&E valves) has only ran about 3,000kms.
It brings my GT3040 (GT3082R) with 0.82 rear on around 3800rpm and easily pulls to current 8200rpm redline.
The turbo is bolted to a custom made steampipe manifold with 46mm Tial xwg. Cams are Crower 280's.
I can drive around town off-boost all day every day and still use less fuel than my mates with stock Evo's!! :lol:
It's still on a basic street tune that ran 12.5 at WSID a few weekends ago so there's a lot of room for improvement when dyno time comes

BTW a GT3040/GT3082R is the same as a GT35R turbo except it has a slightly smaller turbine wheel to bring it onto boost a little bit earlier than a GT35R = said to be ~500rpm.
It suits a 2L when you want to shift the powerband upwards, or for a stroker as it sits in between a GT3076R and GT35R.
On a 2L, I'd probably be looking at downsizing to a GT3076R instead with 272 cams and a 38mm xwg.
Ive contemplated even selling or swapping my GT3040R to replace it with a GT3076R instead... but I wanna see what the current package does on a dyno first.

 

[DOUGMO]

I recently did back to back with a 3082 and a 3076gtx on a 3sge mr2 with a fully built engine with all the fruit.

The 3082 ran a .82 the 3076 a .63, The 3082 was only slightly less responsive coming onto boost on the dyno
but felt way less responsive on the road.
The 3076gtx also made more power on the same boost.
in saying that I prefer a normal 3076 with the 4" anti surge cover over a GTX, nice turbo.

 

[ONPSI]

I agree with George there, the 3076 with the anti surge cover sounds mad when it comes on boost you can't mistake that squeel the anti surge cover makes.
Also having had the 3076 on my previous III was well worth it.

 

[EVO-00X]

The 3082 ran a .82 the 3076 a .63, The 3082 was only slightly less responsive coming onto boost on the dyno
but felt way less responsive on the road

Wow, I thought the difference would have been a lot more noticable. What sort of boost levels was that at George?
The bigger turbo with larger 0.82 rear housing vs smaller turbo with smaller 0.63 rear housing is never going to be as responsive or make as much power midrange on the same boost setting.
On the 2L, when does the GT3076R power curve start to drop off with the 0.63 rear end?

My 3082 feels very linear in delivery. It doesnt smash you as hard in the seat a smaller turbo does, but it pulls all the way to current redline.
Ive been in a 4G63T with a GT3076R with 0.63 rear and the power felt that it was dropping off around 6500-7000rpm.
But the same turbo then went on the same engine when it was stroked, but boy did it boogy down low early but the power dropped off early again.
I have no doubt that its a great turbo for a 2L and I loved the sound of it on my friends 4G63, but would it be better off mated to the 0.82 rear housing rather than the 0.63?

 

[DOUGMO]

The boost was set around 22psi, I was trying to make two points really.

Firstly the GTX made more top end power with the smaller rear housing,even on a realatively low boost level.
And I would say that it would really pull away from the 3082 on 28-30psi.
(garrett say it only pulls away above 25-26psi which makes sense)

And the second point is that the GTX is relatively laggy even with the .63 which I would put down to the
big compressor wheel.

They both made peak power just over 7000rpm but held on ok to close to 8000rpm (only slight drop in power)
Both hitting full boost at around 4300-4500rpm

IMO the gun setup out of those two would be a GTX3076 with a .82 as long as it was running over 28psi,
There probably wouldnt be much if any extra lag as it would be breathing better overall.

The S13 I race has an old school 3076 with a 3" comp cover and .63 and that hits full boost at 4000rpm and
punches hard up to 7500rpm (stock sr20 with cams)

As I said above my preference over all of them (sub 25psi) is a 76 with the 4" anti surge, great turbo even though
its relatively old

 

[Galantman]

thanks for the info guys, certainly going for at least 272's if not 280's. surprised at how conservative they are compared to stuff listed for the old astrons. just need info about where to source them from now.

 

[DOUGMO]

If you get a 272 with decent lift that should be plenty, they can vary a lot.

I had 272s before and I've actually gone back to 264s now, but the 264s have 1mm more lift than the old 272s

 

[EVO-00X]

So at the end of the day, if running 98 pump fuel and <24psi boost, go the old school GT3076R with 0.63 rear and anti-surge cover on a 2L.
George, do you then think there would be much point to change from the 3082 with 0.82 rear to a GTX3076 with 0.82 rear if running under 25psi on 98 pump?
Hmmm... then if I plan to go E85 and more boost in future the GTX would be the choice hands down.
Dayam I need to get a full tune to get the numbers and make some comparisons :lol:

 

[DOUGMO]

I would just go the GTX and man up with the boost lol.

I think an old school 3076 with anti surge would be better over the 3082

 

[Galantman]

so no suggestions on suppliers? im thinking of Kelford 280/272 + springs and retainers for about $1400 delivered from Kiwi land.
anybody out there used these?

 

[DOUGMO]

they will be mega angry for the street, should sound tough though.

you can buy direct from kelford or try tuspeed in melbourne

 

[Galantman]

im happy to be "angry". will purchase direct from NZ. local shop quoted $980 for cams alone, yet had never heard of them and just looked on the PC for what they had. not exactly a confidence inspiring sales technique.
Im still waiting on 1 price and brand from another business before final decision.

still amazed at how some people run businesses, went it 1 workshop and it seemed a bit like boys + toys trying to convince me at all costs to use them. they may know their stuff. but presentation wasn't great.