Camshaft Choices

[DJGTR]

I recently stuffed my engine on my r32 gtr and i have just been approved for a loan so now comes the fun part deciding on what parts i want to use.

I pretty much have my heart set on a HKS step 2 stroker kit and HKS GTRS turbo's.

The car will be used mainly for street with the odd drag meeting thrown in for fun. I am thinking about the tomei poncams type b 260 in/ex but i dont know if these will be ok or if i need to go something larger?

Also what oil pump do you guys seem to think is the best? (not going dry sump)

I already have these parts off my old engine.

Apexi pfc pro

Apexi pods

r33 gtst afm's (dont know if these will be up to the task may need z32)

Sard 800cc injectors

Nismo fuel pump

Nismo fuel regulator

Trust 600x300x100 fmic

HKS oil cooler

GReedy hard pipe kit

3.5 inch catback

(unsure what frontpipes and dumps)

Thnx in advance

Dave

[Sydneykid]

I recently stuffed my engine on my r32 gtr and i have just been approved for a loan so now comes the fun part deciding on what parts i want to use.

I pretty much have my heart set on a HKS step 2 stroker kit and HKS GTRS turbo's.

The car will be used mainly for street with the odd drag meeting thrown in for fun. I am thinking about the tomei poncams type b 260 in/ex but i dont know if these will be ok or if i need to go something larger?

Also what oil pump do you guys seem to think is the best? (not going dry sump)

I already have these parts off my old engine.

Apexi pfc pro

Apexi pods

r33 gtst afm's (dont know if these will be up to the task may need z32)

Sard 800cc injectors

Nismo fuel pump

Nismo fuel regulator

Trust 600x300x100 fmic

HKS oil cooler

GReedy hard pipe kit

3.5 inch catback

(unsure what frontpipes and dumps)

Thnx in advance

Dave

Hi Dave, you have some serious mismatches in your plan;

1. HKS stroker crank, good for 1000 bhp plus and 10,000 rpm or so

2. GTRS turbos = 800 bhp or so and need 6,500 rpm to get decent boost

3. 800 cc injectors = 800 bhp

4. R33GTST AFMs = for 750 bhp, Z32’s for 800 bhp and Q45’s for 1000+ bhp

5. Nismo fuel pump = 600 bhp

6. Nismo fuel regulator = not required, the injectors are large enough for the turbos

7. 3.5” cat back = 650 bhp (quiet enough for road use)

8. Trust 600x300x100 fmic = 900 bhp or so

9. Tomei Poncams type b 260 in/ex = 650 bhp and ~8,250 rpm max, like boost build at around 4,500 rpm

Plus you have some items missing, a triple plate clutch for a starter, then valve springs, porting etc etc. There is easily $10K in the bits that you haven’t mentioned.

You really need to have a good think about what it is you are trying to achieve. Based on my experience “800 bhp” (the most common number above) and “mainly for street” shouldn’t be used in the same sentence. A nice street GTR is around 600-650 bhp, over that and they get cranky, lumpy, laggy, slow to build boost and damn hard to get moving smoothly from a standstill. Unless you make a lot of noise and wheelspin you will get dragged off across the intersection by repmobiles.

So to answer your question, the Tomei 260 Poncams are too small for the GTRS’s. You need to be looking at 272’s with some decent lift, certainly over 10 mm. You might get away with 264 on the inlet and 272 on the exhaust. It will make it slightly less lumpy, but compromise the top end slightly.

cheers

[SLIMVLT]

so do u think that tomei pon cams cams are able to be mixed and matched. like c ould u run 256 on inlet and 260-272 or so on the exhaust and still have it work. would it give more responce or would it just suck hole. i think that runing more duration on the exhaust promoting more scavaging and helping the turbo spool up would be a good thing. inlet would be cool with that cos u have boost shoving air in so i dont c a masive duration 100% nesacary

also with tomei pon cams u would just have to re shim to suit valve clearence or whatever to install it wouldnt u?

there would be no need to replace lifters or anything. just re shim the thing.

this is on a rb25 . (i didnt c the point in starting a new thread)

Edited July 26, 2006 by SLIMVLT

[DJGTR]

Hi Dave, you have some serious mismatches in your plan;

1. HKS stroker crank, good for 1000 bhp plus and 10,000 rpm or so

2. GTRS turbos = 800 bhp or so and need 6,500 rpm to get decent boost

3. 800 cc injectors = 800 bhp

4. R33GTST AFMs = for 750 bhp, Z32’s for 800 bhp and Q45’s for 1000+ bhp

5. Nismo fuel pump = 600 bhp

6. Nismo fuel regulator = not required, the injectors are large enough for the turbos

7. 3.5” cat back = 650 bhp (quiet enough for road use)

8. Trust 600x300x100 fmic = 900 bhp or so

9. Tomei Poncams type b 260 in/ex = 650 bhp and ~8,250 rpm max, like boost build at around 4,500 rpm

Plus you have some items missing, a triple plate clutch for a starter, then valve springs, porting etc etc. There is easily $10K in the bits that you haven’t mentioned.

You really need to have a good think about what it is you are trying to achieve. Based on my experience “800 bhp” (the most common number above) and “mainly for street” shouldn’t be used in the same sentence. A nice street GTR is around 600-650 bhp, over that and they get cranky, lumpy, laggy, slow to build boost and damn hard to get moving smoothly from a standstill. Unless you make a lot of noise and wheelspin you will get dragged off across the intersection by repmobiles.

So to answer your question, the Tomei 260 Poncams are too small for the GTRS’s. You need to be looking at 272’s with some decent lift, certainly over 10 mm. You might get away with 264 on the inlet and 272 on the exhaust. It will make it slightly less lumpy, but compromise the top end slightly.

cheers

Thanks for the reply SK.

600-650bhp would easily do me.

Would going HKS25/30's (or similar garrett) be a better option than the GTRS?

I can sell my 800cc inj as they are new and unused and go for some 700cc if thats a better option.

Would the HKS step 1 stroker kit be a better option for me?

I already have a hks twin plate (forgot to mention it) would this be sufficient for 600-650bhp?

P.S my budget is about 22k

[1q2w3e4r]

I don't really see why a stroker kit is one of your main priorities you can make 600-650 bhp easily enough with the standard displacement.

If you want to rev the arse out of it your going to need valve springs, retainers, some major head work and a big set of cams. You'd probably want a surge tank and duel pumps if you were going to be doing a bit of drag racing as well with a big strong clutch.

Have you been and spoken with any workshops about your goals and budget?

[Munna1]

-hks 2550's would be perfect for 600 to 650hp

cheers

[Sydneykid]

Thanks for the reply SK.

1. 600-650bhp would easily do me.

2. Would going HKS25/30's (or similar garrett) be a better option than the GTRS?

3. I can sell my 800cc inj as they are new and unused and go for some 700cc if thats a better option.

4. Would the HKS step 1 stroker kit be a better option for me?

5. I already have a hks twin plate (forgot to mention it) would this be sufficient for 600-650bhp?

6. P.S my budget is about 22k

Suggestion follows;

1. OK

2. Yep

3. Not necessary, the Power FC will run 800 cc injectors perfectly

4. Why are you looking at a stroker kit anyway, the standard crank will do just fine.

5. Should be OK

6. That'll do it, with some change if you are frugal

cheers

[DJGTR]

I don't really see why a stroker kit is one of your main priorities you can make 600-650 bhp easily enough with the standard displacement.

If you want to rev the arse out of it your going to need valve springs, retainers, some major head work and a big set of cams. You'd probably want a surge tank and duel pumps if you were going to be doing a bit of drag racing as well with a big strong clutch.

Have you been and spoken with any workshops about your goals and budget?

I really want a stroker kit for better response. I dont want a stupidly high rev limit maybe just 500-750rpm above stock. Also i have an early r32 so the crank has the dud oil pump drive and i dont like the idea of a crank collar so my only options are aftermarked crank or r33 crank which i heard are $1000 and hard to come by. The HKS step 1 kit is $6466 delivered. If you add up the price of a r33 crank, forged rods/pistons/rings for a few thousand more i can have a stroker with better response, better off boost power and a better balanced bottom end.

what you guys think? am i going for overkill?