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What Cams To Go With On Rb26 Build.

MJTru

By MJTru,
in Engines & Forced Induction

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MJTru Mentor

MJTru

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Posted (edited)

Ok I have been asking for advice on my build and as we speak. I have got the following parts.

1. Set of rods and pistons. Manley rods with 625 bolts, cp pistons with 9310 pins.

2. Tomie over size oil pump

3. ACL race bearings.

4. ARP head studs and main studs.

5. Cometic 1.3mm thick head gasket

6. 1.1 head oil restrictor

7. Supertech intake and exhaust valve seals.

8. Head oil drain kit.

9. New OEM cam and rear oil seals.

Im waiting on a new oem crank with the long oil pump drive and a new cylinder head. With some valve and spring. Then I can start the build.

I have a few queation regarding a set of new hks cams and for my goal of 600 hp should I use them. I plan on drag racing the car more than driving ir on the streets. I have a stock r33 gtr for street use.

The cams specs are stock lift but 272 duration. I dont have much experience with cames as I always go stock cams on my builds. The biggest difference going from a gtst to a gtr is that I just launch the hell out the gtr rpms are in the 8000 area all the time. Will these cams help me or slow me down for my 600hp goal.

My next problem is. I know of the rb oil issues and have never had real big oil pump failures in the past. Thats on rb25 builds. Now with this new oil pump. (Tomie) should I go with the ovwrsize oil pan or is it a waist of money?? I see that Raw Brakerage has a service to inlarge my pan for 1100 usd. They also put the head return on the pan but on the intake side. Is this a good idea.

Edited by MJTru
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sleptema Proficient

sleptema

Posted
Posted

I am definatly no expert on this topic but I would have thought your valve train would be the most limiting factor on deciding what cams you go, not power. I personally would go high lift high duration because an increase throughout the entire powerband would be advantageous. But I assume you are worried about valve float because of the high rpm launches?

MJTru Mentor

MJTru

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I didnt choose these cams they came with the motor from japan. Valve float did cross my mind. The turbo is a PT 6262.

I personally was planning on selling them and going for stock ones, cams that is. I got the set of valve springs for stock lift. I was told that I can increase the lift a little. But will be fine use the hks cams. Yes I was told by the old owner of the car that the cams are stock lift and 272 duration. These numbers didnt come from me but the person who got them. In my head thats risky.

Im already turned off. So I guess ill just get a set of stock cams.

I can remember reading an old thread where people made better power using there oem cams over several brands out there. It had mentioned that if the whole valve train wasnt looked at it may be better to go back to the stock cams.

Any ideas on the oil pan.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Any ideas on the oil pan.

Read the oil control thread or if you don't want to read all of it just the first few and last 10 pages say.

The Tomei pump should not fail but it can empty your sump. The restrictor will help. The head "drain" will not but if you are going to fit it the exhaust side is preferred. The enlarged sump is also good insurance against engine failure...although the price looks high - are there alternatives? I would recommend drilling and tapping two holes as high as possible in the inlet side which you can plug if you are not going to run breathers. That way if you do decide you need breathers later you won't have to pull the engine and remove the sump.

MJTru Mentor

MJTru

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I have done a lot of reading in those threads but thats about a year ago. I decided to go with the head drain as insurance. I understand by putting the restictor in the head will reduce the amount of oil in the head and really make the head drain redundant.

I was looking over the oil pumps manual and it does say that I need a enlarged oil pan.

Does anyone know of another option thats cheaper that 1100 usd offered by raw brokerage. It looks to be a very clean unit with extended oil pick up and oil pan baffles.

As for the cam. Yes sir. Its intended for drag racing. I will attach the supertech part number for the valve springs.

With such duration I will need stiffer springs to avoid floating valve effect right. This is the reason I want to post the part number I got.

I have heard that this duration will kill low end power but make up for it on the top end.

Can you please explain just a little about the subject. Like pros and cons.

Edited by MJTru
sleptema Proficient

sleptema

Posted
Posted

I have done a lot of reading in those threads but thats about a year ago. I decided to go with the head drain as insurance. I understand by putting the restictor in the head will reduce the amount of oil in the head and really make the head drain redundant.

I was looking over the oil pumps manual and it does say that I need a enlarged oil pan.

Does anyone know of another option thats cheaper that 1100 usd offered by raw brokerage. It looks to be a very clean unit with extended oil pick up and oil pan baffles.

As for the cam. Yes sir. Its intended for drag racing. I will attach the supertech part number for the valve springs.

With such duration I will need stiffer springs to avoid floating valve effect right. This is the reason I want to post the part number I got.

I have heard that this duration will kill low end power but make up for it on the top end.

Can you please explain just a little about the subject. Like pros and cons.

I was pretty sure tomei/hks/nismo did sump baffles, but nothing is going to be as reliable as an extended sump, especially at the high rpm for drag racing. I would do it just for the reliability of the engine.

I think by low end they mean 1-3k. Which for a drag car you will use 0% of the time. I believe the reason the low end suffers is because before the turbo begins to spool you are essentially trying to suck air in, and with a huge duration, it becomes null and void, but as soon as the boost kicks and it starts to push all the air in, the duration and lift begins to shine because you are able to force so much more air in, in comparison.

I am not sure about the figures, but I believe stock is 9.15 lift, 264 duration?, hks step2 is 10.15, 272 duration? That is hell of a lot more air. I was reading the rb26dett tuning page and it said someone got a 60hp increase just from cams and adjustable cam gears.

Obviously if money wasn't an issue, vct would make up for the loss of power low end...?

MJTru Mentor

MJTru

Posted
  • Author
Posted

Supertech SPRK-M1007S/RB

Specs:

Outer Spring O.D.: 28.10mm

Outer Spring I.D.: 20.00mm

Seat: 70 @ 40.7 (lbs@mm)

Open (lift): 188 @ 11 (lbs@mm)

Max net lift: 16.00mm

Coil bind: 24.70mm

Rate: 10.50 lbs/mm

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

Does anyone know of another option thats cheaper that 1100 usd offered by raw brokerage. It looks to be a very clean unit with extended oil pick up and oil pan baffles.

These are popular here but freight might kill it for you:

http://www.trademe.co.nz/motors/car-parts-accessories/nissan/engines/auction-654508309.htm

MJTru Mentor

MJTru

Posted
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Posted

Piggaz is right those are the stock cam specs.

But can anyone answer my question as to the supertch sping specs will work or not. Eather hks steps in sure of the duration, but ill mesure the lift today and tell you.

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