Cams for -5s

[r34unit]

Hi

What's the best camshafts for -5 turbos on e85 with forged bottom end (rb26), thinking of using supertec gear to rebuild head.

 

Thanks in advance

[GTSBoy]

Depends.  -5s, being big turbos, are really working at their best up high in the rev range.  So if you were to take the view that your "best" cams are the ones that work in the same range, then you're looking for longer durations.  270° or maybe even more.  But if you take the view that -5s are a miserable thing that leaves your engine gasping for torque until they come on boost, then you'd choose some smaller cams, maybe 260°, and dial them in to work well below the turbos' optimum range, to try to get them onto boost a fraction earlier.  Either way, pack in as much lift as you can within budgetary limits.

Usage model really helps here.  Street or track?

[Dose Pipe Sutututu]

Save the money on cams for a modern twin scroll setup with a twin scroll single turbo.

A single EFR8374 would do everything better than your twins with cams blah blah using the stock cams.

[r34unit]

Cars will be mainly for street duties!

[Mick_o]

^^^Still as above...Better on the street or the track than the 5s!

By hundreds of rpm's plus more power everywhere plus more reliable ?

[infamous_t]

I'm running -5s on e85 (flex setup) with Tomei Type Bs.
They're a bit average on on 98 alone, but e85 really wakes the turbos up, mid range and boost response improved very noticeably from seat of my pants view.

I'm boost limited due to an otherwise high km stock motor, a forged build with more boost would be pretty good thing with this setup IMO.

[r34unit]

I'm running -5s on e85 (flex setup) with Tomei Type Bs.
They're a bit average on on 98 alone, but e85 really wakes the turbos up, mid range and boost response improved very noticeably from seat of my pants view.
I'm boost limited due to an otherwise high km stock motor, a forged build with more boost would be pretty good thing with this setup IMO.

Nice
Do you have a dyno graphic to share ?

[Dose Pipe Sutututu]

Full boost comes on about 4.7 to 5k?

EFR8374 probably do it all close to 4k, make more torque and power across the entire RPM range too.

[Piggaz]

Here is my result, although it's a 2.8 it is using -5 snails. Basic spec is...

- 2.8 (9.0:1 comp)

- -5 huffers

- E85

- Twin 3 inch exhaust

- heavily modified head (Naprec chamber modified, 1.5 mm OS in and out)

- cams are a 260 at 10.85 mm with quite an agro ramp rate. The duration at 50 thou is 232 degree's which is the same as Camtech's baby drop in but with 1.7 mm of lift more. 

How hard do you want to rev it?

Where do you want your curve to be strongest?

Whats your tolerance to a lazy bottom end? 2.6/-5's isn't particularly strong sub 5000 RPM.

[anthonymcgrath]

Thought I'd weigh in here my mate has got fully forged engine.. still a 2.6 with new crank forged pistons and rods. Tomei ponscams and 1.8mm head gasket. All supporting work and -5 turbos

Hes currently limited to 6800rpm and 1.2 bar (small boost leak currently too so less than that)

As stated below 4-4500 there ain't much going on in fact it's winding him up now. However the tuner said it's quite a mild tune to let him get used to it and limited rpm cos fresh engine build. He said there's lots to go yet... including 1.6 bar boost

He got some adjustable cams to go in to advance ign a couple degrees but even with that and a map tune and more boost he will still be at the 4000 to 4500 rpm range if I'm lucky.

So to that end hes going with nitrous to help the car in that low and mid range so it takes off like a 3ltr twin turbo diesel taxi lol.

Yep he could go top mount.. New big turbos are mental.. I love em but he wants to keep the twins setup and he got tired of manifolds cracking on him with his gtst... maybe down the line but by then a 35 gtr engine will prob be affordable or the car itself lol!

In the meantime I think nitrous is a good way to go for immediate shunt and power and then at 5000 let the turbos do the work. All told with 1.6 bar the car will see about 600+ bhp so that's pretty crazy then 80bhp nos on top is gonna make things rather cartoony lol.
I've heard ppl scoff.. "uhh nitrous is fake power" ...cant stand that rubbish personally.. if it's installed right and connected up and ecu controlled it's every bit a part of the car as anything else and it's a great way to get rapid power.

Just our 2 pence:)
Ant

[No Crust Racing]

Talk to Kelford about your goals. He was fairly accurate about my result and great to deal with. 

Consensus seems to be that Tomei drop in's are very mild and lots of people seem to end up dissatisfied. 

[r34unit]

I want to achieve 250kw at 4K and 450kw plus in the top end.

[Piggaz]

250 kw at 4000 RPM out of a 2.6 using -5's? You're going to struggle, mate.

Whats the rest of the setup? Head been touched?

* I would STRONGLY suggest not running -5's up around 450 Kw + at the treads. They will not last! 

[infamous_t]

On 2017-5-25 at 1:48 PM, r34unit said:

Nice
Do you have a dyno graphic to share ?

Yep, from my build thread.
 

On 2015-3-12 at 8:35 PM, infamous_t said:

[anthonymcgrath]

I'm running -5s on e85 (flex setup) with Tomei Type Bs.

They're a bit average on on 98 alone, but e85 really wakes the turbos up, mid range and boost response improved very noticeably from seat of my pants view.

I'm boost limited due to an otherwise high km stock motor, a forged build with more boost would be pretty good thing with this setup IMO.

 

Just checked your graph out too what boost are you running? Mate running 1.2 currently it's quick but like your graph there up until 4500 it's a bit dull heh

It's going back in a week or two for 1.6 bar boost and some adjustable pulleys to help advance ign a touch. It's not going to radically change it before 4500 but it'll help.. that's where the nos will make it more amusing heh.

I've heard at 1.6 bar these turbos are just silly making 600+ and some ppl have reported 700 so they seem like good hard working turbos overall. I do miss that low down response tho.

 

It does seem clear at some point to get top mount... a gen2 gtx3582r or precision 6266 which is the turbo everyone seems to jump on for a gtr but I wonder how a gtx3076r would be because I had one on my ol gtst and it was silly responsive down low and the new ones make 550hp+

I think after that for pure response it's an e85 setup or just look into an rb30 for end grunt.

Just saturday morning musings lol...

 

[GTSBoy]

34 minutes ago, anthonymcgrath said:

 

 some adjustable pulleys to help advance ign a touch.

That's the 2nd time I've seen you post that.  You do realise that there's "timing" and there's "timing" and they're not the same things, right?  Cam gears are for valve timing.

[anthonymcgrath]

Yep sorry my wording is wrong I know it's for the valve timing not ign timing lol.

I don't won't if ill be seeing radical adjustments off a couple of extra degrees of cam timing tho? Can you give any thoughts?

[GTSBoy]

Not radical, no.....but worthwhile.

[pol1on1]

Im after cams too. budget is wife got my cards not much!
Stock head n block
98
-5's
19psi
Full 3inch pipes all da way i think
Make 412whp
She start to wake up at 4.5k ish

Want it to spool up earlier but can i get more top end hp ? Can we get two things at once.
Sorry 4 highjack

[GTSBoy]

Yes you can.  Lift is the answer to both.  Longer duration + dialling them in to boost the midrange more than the top will also help both.