Rb25det Neo Mod Questions

[Swole]

Hey guys,

Couple questions in regards to modifications to an rb25det neo in an R34

If I decide on dropping in Tomei poncams, would I need to upgrade springs and retainers too?

Obviously it would be beneficial to do so however due to potential budget restrictions, it may not be an option

If the answer is yes, then I may turn my current internally gated Hypergear Atr43ss2 into external gate and be able to afford to do valve springs and retainers

If the answer is no, then I may use the funds to upgrade to an externally gated Atr45 instead

Any input, advice or feedback is appreciated

Thanks

Edited May 20, 2016 by Swole

[GTSBoy]

Which cams? How hard do you plan to spin the motor? What are you using it for?

[t_revz]

If the answer is yes, then I may turn my current internally gated Hypergear Atr43ss2 into external gate and be able to afford to do valve springs and retainers

I would think by the time you buy a gate and modify pipe work you won't "make" any cash

[Swole]

Which cams? How hard do you plan to spin the motor? What are you using it for?

Tomei 260 drop ins

Aiming for around 350rwkw mark on eflex

Using it mainly for street use

I would think by the time you buy a gate and modify pipe work you won't "make" any cash

True, however that would still cost less then buying an Atr45 with chra roller bearing + labour then to externally gate my current one

[GTSBoy]

Well, the definition of "drop in" implies that you don't need to change anything else. But when you couple the increased mechanical loads from the cam AND the boost level you need to make 350rwkW, you do start to worry about valve float. As usual, YMMV. I'd suggest that the usual approach is to suck it and see. That doesn't work if total budget is a problem though. If it were me, I'd not change the cams at all, and save all the money.

[Swole]

Well, the definition of "drop in" implies that you don't need to change anything else. But when you couple the increased mechanical loads from the cam AND the boost level you need to make 350rwkW, you do start to worry about valve float. As usual, YMMV. I'd suggest that the usual approach is to suck it and see. That doesn't work if total budget is a problem though. If it were me, I'd not change the cams at all, and save all the money.

This is true

Thanks

[hypergear]

A good stock Neo engine doesn't valve float we were running them toward 30psi and they are fine.

The Cams are not required on the Neo either. Stock cams on ATR45SAT is good good enough to support towards 400rwkws on E85 fuel.

For externally gated setup the ATR45SAT in Ceramic ball bearing setup will be making alot more power then the ss2, and specially if its an older version SS2 its not laggier. You can get some where towards 370rwkws using it internally gated. But it needs a big PWR cooler and at least 4 inches exhaust to get there.

[Swole]

A good stock Neo engine doesn't valve float we were running them toward 30psi and they are fine.

The Cams are not required on the Neo either. Stock cams on ATR45SAT is good good enough to support towards 400rwkws on E85 fuel.

For externally gated setup the ATR45SAT in Ceramic ball bearing setup will be making alot more power then the ss2, and specially if its an older version SS2 its not laggier. You can get some where towards 370rwkws using it internally gated. But it needs a big PWR cooler and at least 4 inches exhaust to get there.

I was going to PM you later down the track asking whether I would need to upgrade valve springs and retainers (or even head gasket) to make close to 400rwkw with an ATR45 roller bearing!

Cams has simply been a long term personal goal for me haha

Thanks

Edited May 20, 2016 by Swole

[Artic Choc]

i have tomei type b cams in mine, as well as an older SS2 ex gate currently making 324kw on 16 psi and e70. with bigger injectors (maxed 725cc atm) and more boost mine would see 350kw+ easy on e85 just an indication of what you could do

[KiwiRS4T]

Spend your money on turbo, wastegate, fmic, exhaust, injectors, fuel pump, AFM if necessary, (I presume you already have an aftermarket ecu or a Nistune chip) - these are the priorities - you can save up for cams later if you really want.

[Swole]

i have tomei type b cams in mine, as well as an older SS2 ex gate currently making 324kw on 16 psi and e70. with bigger injectors (maxed 725cc atm) and more boost mine would see 350kw+ easy on e85 just an indication of what you could do

That's awesome

Planning on upgrading the injectors?

If I can get away with it, I might go with an ATR45 with cams on flex/85 and aim close to 400rwkw

[Swole]

Spend your money on turbo, wastegate, fmic, exhaust, injectors, fuel pump, AFM if necessary, (I presume you already have an aftermarket ecu or a Nistune chip) - these are the priorities - you can save up for cams later if you really want.

Already got a complete Plazmaman set up including plenum, throttle and intercooler running a Haltech ps2000. Gotta upgrade the injectors and pump for 85 which I've already included in my budget

Edited May 21, 2016 by Swole

[Artic Choc]

That's awesome

Planning on upgrading the injectors?

If I can get away with it, I might go with an ATR45 with cams on flex/85 and aim close to 400rwkw

Wont be upgrading injectors im happy with it for now... i have other plans for the car atm. Why not go a gtx35r and faceroll 400kw?

[Swole]

Wont be upgrading injectors im happy with it for now... i have other plans for the car atm. Why not go a gtx35r and faceroll 400kw?

Fair call

Correct me if I'm wrong cause I haven't looked much into it, but an ATR45 is cheaper and I'm staying low mount

ATR45 has also been proven to exceed 400rwkw, however that's with upgraded springs and pistons

I'll be consulting with Tao on whether I'd be able to get away without upgrading those to achieve close to, if not, 400 on e85

[discopotato03]

For my 10c I believe there is type A and B Poncams for the Neo Turbo 25 and I would go for the type As or OE cams .

From memory the type As are about 252 duration and the type Bs 260 .

Where the Neo has it over the R33 25DET engine is a bit more lift and more aggressive lift ramps on the cams . This obviously didn't work with the R33s hydraulic buckets hence the solid ones and shim adjustment .

I believe Nissan was looking to pull the torque peak down the rev range on the GTt hence better valve train and different inlet manifold volume .

I think the longer period B cams would cost you low down part throttle torque and be less suited to the NEOs manifold .

One here with a Neo type Stag went B cams and regretted the decision later .

You call , mine would be standard or at most the shorter Poncams .

A .

[AngryRB]

Dont these neo guys rev out higher than r33's, ive seen them go well over 7k which type b's would be in the zone. I got some for the 2530neo so hopefully they'll aid the flow

[iruvyouskyrine]

Standard cams/springs/retainers good for over 400kw. Nissan did good, leave it standard.

[Dose Pipe Sutututu]

What's wrong with stock cams?

Recently a R34 done by Chequered Tuning spun over 400kW using a Hypergear ATR45SAT turbo.

[Swole]

For my 10c I believe there is type A and B Poncams for the Neo Turbo 25 and I would go for the type As or OE cams .

From memory the type As are about 252 duration and the type Bs 260 .

Where the Neo has it over the R33 25DET engine is a bit more lift and more aggressive lift ramps on the cams . This obviously didn't work with the R33s hydraulic buckets hence the solid ones and shim adjustment .

I believe Nissan was looking to pull the torque peak down the rev range on the GTt hence better valve train and different inlet manifold volume .

I think the longer period B cams would cost you low down part throttle torque and be less suited to the NEOs manifold .

One here with a Neo type Stag went B cams and regretted the decision later .

You call , mine would be standard or at most the shorter Poncams .

A .

Correct

However I do want the 260 duration

Dont these neo guys rev out higher than r33's, ive seen them go well over 7k which type b's would be in the zone. I got some for the 2530neo so hopefully they'll aid the flow

Mine does

Standard cams/springs/retainers good for over 400kw. Nissan did good, leave it standard.

This is what I'm thinking

What's wrong with stock cams?

Recently a R34 done by Chequered Tuning spun over 400kW using a Hypergear ATR45SAT turbo.

Nothing's wrong

Oo was that unopened head?

Cams have just been a goal for myself, really just after the lump/response shockingly haha

Main question is whether I'd need to also upgrade the springs/retainers/(headgasket) if I did cams and went for 400rwkw

Appreciate all the input though!

[Ben C34]

You will barely notice any lumpy idle with poncams