The Sr20/Sr22vet thread

[jr_ss]

Originally Posted by livelovesole

Thank you alot for the information. I do plan on running a twin scroll setup, sorry for not metioning earlier and I'll deffitnitly look into/ consider the gtx35. First time building something to this caliber, want to be safe. Do you think springs are necessary on a P12 head for my power goals? Assuming their supertech det springs that you use.

I think the P12 head is just an expensive piece of hardware that doesn't benefit you in anyway shape or form over a P11 head with the same cams. I have yet to see flow numbers for a P12 head. The only thing that supports this claim are the components in the head and slight changes in the casting. They have weaker valve stems(smaller diameter), require custom spring retainers and are more expensive to acquire. The only benefit are the cams are much better than the P11's but that doesn't matter if you're swapping them anyway.

You will need to upgrade your valve springs. You can run the factory P12 springs with the P11 inners for a cheap upgrade. They experience valve float in the higher Roma without an upgrade.

[hanzbrady]

Originally Posted by jr_ss

I think the P12 head is just an expensive piece of hardware that doesn't benefit you in anyway shape or form over a P11 head with the same cams. I have yet to see flow numbers for a P12 head. The only thing that supports this claim are the components in the head and slight changes in the casting. They have weaker valve stems(smaller diameter), require custom spring retainers and are more expensive to acquire. The only benefit are the cams are much better than the P11's but that doesn't matter if you're swapping them anyway.

You will need to upgrade your valve springs. You can run the factory P12 springs with the P11 inners for a cheap upgrade. They experience valve float in the higher Roma without an upgrade.

This is 100% on point, I never recommend the P12 cylinder head due to the aftermarket available for it. A P11 head can easily out perform the P12 especially with our CNC porting that we offer.

[candyred_240sx]

Originally Posted by brndck

thats excellent. i'd love to see a dyno run! is your engine just sleeved and bored out or stroked also?

Thanks man.

I will post up the dyno sheet tonight. The block is sleeved, 87mm bore with 91mm stroker crank.

At this power before with a non sleeved block the cylinders ovaled

[RalliartRsX]

Originally Posted by jr_ss

I think the P12 head is just an expensive piece of hardware that doesn't benefit you in anyway shape or form over a P11 head with the same cams. I have yet to see flow numbers for a P12 head. The only thing that supports this claim are the components in the head and slight changes in the casting. They have weaker valve stems(smaller diameter), require custom spring retainers and are more expensive to acquire. The only benefit are the cams are much better than the P11's but that doesn't matter if you're swapping them anyway.

You will need to upgrade your valve springs. You can run the factory P12 springs with the P11 inners for a cheap upgrade. They experience valve float in the higher Roma without an upgrade.

Agreed for the most part. For example; P12 head has the 5.5mm exhaust valves vs the 6mm valve. Also, the casting for the P12 head seems to shroud the valves a bit more (it seems the P11 head is better in this regard, but it may still be hit or miss as sometimes the cast would shift during manufacturing).

However, all depends on what the owner wants to run.
P12 head comes with the CAS, coil packs and the valve cover (about $600 in value by themselves). So once you sell everything else off associated with the 6spd FWD and internals (pistons/rods, etc), if one wanted to keep it simple, all you would have to do is go Nismotronic and done. John with the Camo S14 made well over 1000WHP and ran deep into the 8s, used Nismotronic until this year, when he switch to Haltech.


Also, a gentleman did do a flow bench test of a P12 vs a P11 head as recently as of last week (I have the images and flow numbers somewhere). However, he switched out the 5.5mm exhaust valves for the 6mm (which anyone turbocharging this setup will do). As it turns out, the P11 did better up top but fell short a few cfm below .250. The gentleman mentioned the valve shrouding being an issue (and ofcourse, the thicker valves as a good amount of flow is gained from going to a skinnier valve).

Either way, you can't go wrong with either livelovesole. Just make sure you lay out your plan of action, as that can be a $500-$1000 different in prep work (I think the machine shop quoted me $125 + parts for new valve guides (it didn't matter if it was 5.5 or 6 as the work is the same) and redoing the seats). In addition, the P11s do have problems with exhaust valve guide leakage in particular, so I would address those if at the machine shop as cheap insurance.

EDIT 1: Inlet manifold should be the same cost throughout and you can run the P11 dual valve springs (from Supertech) and be just fine if you end up with a cheap P12 head.

EDIT 2: P12 has better cams than the P11.

EDIT 3: With the P12 swap, you will need the P11 oil pimp spacer (P12 is two piece, P11 is correct one piece shorter spacer)

In all honesty, if I was to do it again, I would buy a P12 full swap, sell everything not related to the RWD swap, drop in P11 supertech spring and 6mm exhaust valves, slight deshroud and run nismotronic.

[brndck]

Originally Posted by candyred_240sx

Thanks man.

I will post up the dyno sheet tonight. The block is sleeved, 87mm bore with 91mm stroker crank.

At this power before with a non sleeved block the cylinders ovaled

dang. i'll have to be careful. I'm running 87mm pistons (CP VE pistons), no sleeves, but I'm only aiming for just over 500whp on pump gas.

[jr_ss]

Originally Posted by brndck

dang. i'll have to be careful. I'm running 87mm pistons (CP VE pistons), no sleeves, but I'm only aiming for just over 500whp on pump gas.

There are plenty of people deep into the 600's on factory sleeves, albeit I'm unsure of their bore size. You should be fine.

[candyred_240sx]

Originally Posted by jr_ss

There are plenty of people deep into the 600's on factory sleeves, albeit I'm unsure of their bore size. You should be fine.

When this happened to me Mazworx informed us that they have seen this happen with factory sleeves before.

I would assume stock bore or .5mm over is safer but with a 87mm bore the chance of failure is there.

Like you said he should be fine at that power level but if you plan to crank it up you may run into issues.

[LuckyX2]

P12 swap wound up being cheaper than doing a P11. Comes with the CAS so you don't have to buy that or do hall effect and then I sold the cams out of it for more than I could have gotten for P11 cams. Winds up being even more cost effective over a P11 if you want to stay with the P12 cams unlike the N1s I switched to.

Then I used Manley DET single springs and valve seals from a GA16DE. It was cheap.

[brndck]

Originally Posted by jr_ss

There are plenty of people deep into the 600's on factory sleeves, albeit I'm unsure of their bore size. You should be fine.

Originally Posted by candyred_240sx

When this happened to me Mazworx informed us that they have seen this happen with factory sleeves before.

I would assume stock bore or .5mm over is safer but with a 87mm bore the chance of failure is there.

Like you said he should be fine at that power level but if you plan to crank it up you may run into issues.

yeah I have a top-tier engine builder and a very reputable machine shop so I should be good! gonna run 110 octane any time a really crank up the boost too (track/drift use)

[1gr8bar10der]

Originally Posted by 600supersport

With torque being the issue for the clutch, I opted for the Comp twin disc and it's great on track, but I'd seriously consider the spec stage 5+ next time for the likelihood of a much smoother and more streetable feel with a significant torque capacity, but I haven't tried one yet and I don't street or track the car THAT often. It'd be nice if the car was a bit gentler on the stop & go stuff. I guess I'd expect that single to have a higher chance of overheating after some hot laps than the twin would, but that's pure speculation and I'm not out slipping the clutch a lot or kicking it like crazy either so it's a tough call.

Stiff coilovers, stiff mounts and a twin disc clutch are more physically demanding on me after cruising around for a bit, but they're amazing once you're out on track.

Nice job btw candyred. What transmission and cams are you using?

Thanks for the info. My power goal right now is around 500, which is very minimal compared to most people on here lol.

[600supersport]

Seems like a bunch of us in here have relatively similar setups. Anyone ever share timing maps?

[mewantkouki]

Originally Posted by LuckyX2

P12 swap wound up being cheaper than doing a P11. Comes with the CAS so you don't have to buy that or do hall effect and then I sold the cams out of it for more than I could have gotten for P11 cams. Winds up being even more cost effective over a P11 if you want to stay with the P12 cams unlike the N1s I switched to.

Then I used Manley DET single springs and valve seals from a GA16DE. It was cheap.

What are the open and closed pressures for those springs? I've got a set of supertech singles I'm planning on using with my p12 head.

[RalliartRsX]

Originally Posted by mewantkouki

What are the open and closed pressures for those springs? I've got a set of supertech singles I'm planning on using with my p12 head.

I think something like 50 and ???. They are lower than the P11.

The link I posted above, take a look through it. It has all those details at the bottom

[LuckyX2]

Originally Posted by mewantkouki

What are the open and closed pressures for those springs? I've got a set of supertech singles I'm planning on using with my p12 head.

Originally Posted by RalliartRsX

I think something like 50 and ???. They are lower than the P11.

The link I posted above, take a look through it. It has all those details at the bottom

Where are you getting 50 from? Closed is 90lbs, open is 185-225lbs. 248lbs/inch.
http://www.manleyperformance.com/sc/...r20_kits.shtml

[RalliartRsX]

I was referring to stock spring pressures

[livelovesole]

Thank you so much for the great info guys. I just happened to run into a P12 head first so I jumped on it. Brndck: I planned in running the mazworx intake plenum And E85. I was thinking that it would of been better insurance to upgrade the valvetrain but wasn't too sure yet. Ralliart: do you think keeping the 5.5mm intake valves is best then?

[jr_ss]

Originally Posted by livelovesole

Thank you so much for the great info guys. I just happened to run into a P12 head first so I jumped on it. Brndck: I planned in running the mazworx intake plenum And E85. I was thinking that it would of been better insurance to upgrade the valvetrain but wasn't too sure yet. Ralliart: do you think keeping the 5.5mm intake valves is best then?

The stem of the valve isn't the concern with the P12 heads, it's the neck of the valve(4.5mm) which can stretch with the added heat of a turbocharged engine.

Inconel or SS valves are the best when it comes to heat management. Sodium filed play a role in longevity, typically used in OEM applications but do have a limit to heat tolerance, usually 1600*F.

[RalliartRsX]

Originally Posted by jr_ss

The stem of the valve isn't the concern with the P12 heads, it's the neck of the valve(4.5mm) which can stretch with the added heat of a turbocharged engine.

Inconel or SS valves are the best when it comes to heat management. Sodium filed play a role in longevity, typically used in OEM applications but do have a limit to heat tolerance, usually 1600*F.

Jr has it spot on! The neck is actually 4.5mm. This is all to aid in flow and valvetrain weight which ends up being a downfall when dealing with heat.

[s13silvia123]

I assume some of you guys are using aftermarket throttle bodies. Are any of you guys using the one Mazworx provides or a different brand?

[brndck]

Originally Posted by s13silvia123

I assume some of you guys are using aftermarket throttle bodies. Are any of you guys using the one Mazworx provides or a different brand?

I have a q45 90mm one, but I'd love to have a ross or something that was cleaner and shinier.

[rbs14kouki]

Originally Posted by livelovesole

Thank you so much for the great info guys. I just happened to run into a P12 head first so I jumped on it. Brndck: I planned in running the mazworx intake plenum And E85. I was thinking that it would of been better insurance to upgrade the valvetrain but wasn't too sure yet. Ralliart: do you think keeping the 5.5mm intake valves is best then?

Fyi last time i checked . Mazworx only make a manifold for the p11 head not p12 !

[rbs14kouki]

Double post

[hanzbrady]

Originally Posted by rbs14kouki

Fyi last time i checked . Mazworx only make a manifold for the p11 head not p12 !

No, we make them for both the P11 and the P12/20V.

[rbs14kouki]

Originally Posted by hanzbrady

No, we make them for both the P11 and the P12/20V.

my bad !!! Good stuff Hanz

[Yellow4g63]

Originally Posted by hanzbrady

No, we make them for both the P11 and the P12/20V.

Maybe you can help me with this question. What valve springs do you run with the P11 head for turbo? 115? or 138? I remember a few years ago Mazworxs warned about using the 138's because they were showing abnormal wear on the cams? I just don't want to spit a shim out if I bounce off the limiter @9k with N1 cams.

[jr_ss]

Originally Posted by Yellow4g63

Maybe you can help me with this question. What valve springs do you run with the P11 head for turbo? 115? or 138? I remember a few years ago Mazworxs warned about using the 138's because they were showing abnormal wear on the cams? I just don't want to spit a shim out if I bounce off the limiter @9k with N1 cams.

A lot of people run the 9Xlbs springs. Anything over the 12Xlbs cause abnormal wear and really aren't needed.

The Factory P11 springs are actually stiffer than the P12 springs. Cam profiles, particularly ramp profiles play a large role in what spring rates are necessary too.

This page has a list of valve spring seat pressures. http://pulsar.org.au/forums/showthre...l-advise/page3

[1988montecarloss]

kind of off topic but i figure this is where the guys with the most power hang out so would be the best place to ask

is the comp clutch white bunny 6 puck good for 400ish whp? or is there anything better out there in the same price range?

[jr_ss]

Originally Posted by 1988montecarloss

kind of off topic but i figure this is where the guys with the most power hang out so would be the best place to ask

is the comp clutch white bunny 6 puck good for 400ish whp? or is there anything better out there in the same price range?

I preferred the RPS Max Street clutch. You can get it in a 6puck, I ran it with a full face disk at 360whp. Multiple passes at the drag strip, 30k miles of daily abuse. Sold it with plenty of life left on it.

[rbs14kouki]

Originally Posted by jr_ss

A lot of people run the 9Xlbs springs. Anything over the 12Xlbs cause abnormal wear and really aren't needed.

The Factory P11 springs are actually stiffer than the P12 springs. Cam profiles, particularly ramp profiles play a large role in what spring rates are necessary too.

This page has a list of valve spring seat pressures. http://pulsar.org.au/forums/showthre...l-advise/page3

I have 120psi supertech spring in my head

I built my engin with most of the parts that are in my friend sr24vet from mazworx

We took the engin appart lots of time for inspection and no damage to the cams what so ever after 3+ years in fd usa

Oil : redline 20w50 fyi

[Yellow4g63]

Originally Posted by rbs14kouki

I have 120psi supertech spring in my head

I built my engin with most of the parts that are in my friend sr24vet from mazworx

We took the engin appart lots of time for inspection and no damage to the cams what so ever after 3+ years in fd usa

Oil : redline 20w50 fyi

Has he ever spit a shim out?