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datssr

Cam selection for over 450rwhp

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Looking for some fresh opinions on Cam selection for SR20det to get over 450 rwhp.

 

Not a daily driver

 

Combination at the moment is

 

Forged pistons and rods

Upgraded valve springs

GT30 at 25 psi

External Gate

Crow Cams 272 deg 9.5mm Lift

 

Runs out of power at 390 rwhp

Edited by datssr

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GTX3076 .82 will make over 350kW

GTX3576 .82 will make close to 400kW with added lag

 

if you go to a twin scroll housing, with twin gates and a proper twin scroll manifold you can run a slightly larger rear housing and have the same spool/lag as a .82 housing but making more power..

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I didn't even realise you could get crow cams for an sr20 I thought they were a Holden/ford thing.

 

I don't really know anything about the crow cams but 9.5mm lift seems pretty small, are they a standard cam re-grind perhaps?

 

Personally I'm a fan of hks cams, unsure on selection though. What are you using this for? I presume since lag isn't an issue, drag? Most Jap cams will over around 12mm lift.

 

A heap of things could be giving you a bottleneck for more efficiency.

 

This on e85?

Edited by Brodie.Maher

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Yeah well spotted, the turbo on E85 should pull almost around 450 rwhp so the lift would be definitely letting you down. Go Jap cams for sure 272 degree at only 9.5mm lift? That's almost the stock lift in an SR cam :/.

 

If you want the best combination of power and response with high RPM then get the Tomei Procams with 260 12mm IN / 270 12.5mm EX then an adjustable cam sprocket on the exhaust side only while retaining VCT. You can try to keep lash / hydraulic lifter, but after 7000 RPM SR's don't like it as rocker arms tend to snap unless you go solid and remove VCT or risk having it fail at some stage.

 

Is it a dedicated track car or both for street and track?

 

If you were to change turbo, I wouldn't pass this one in twin scroll of course for a street and track car good for 650+ rwhp:

http://www.full-race.com/store/turbos/borgwarner-efr/borgwarner-efr-7163-turbo.html

 

If it was a competition time attack car, I'd push for the 8374. They can reach around 800 rwhp and still have reasonable response for a a higly modified 4 cylinder.

http://www.full-race.com/store/turbos/borgwarner-efr/borgwarner-efr-8374-turbo.html

 

You'd have to be also willing to change to a twin scroll T4 flange for either turbo.

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avoid going solid lifters, stick with the hydrolic and keep the revs under 8000rpm.

 

I used hks 264 in and 272 exhaust with a billet td06 from hypergear. On e85 I made a touch under 500rwhp with more in the setup.

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avoid going solid lifters, stick with the hydrolic and keep the revs under 8000rpm.

 

For a reliable setup I wouldn't recommend anything much over 7000 RPM. This is going based on both experience and my current tuner's advice. The DET valvetrain with hydraulic lifters is too fragile for a reliable setup anything above that. I've snapped a rocker arm at 6000 RPM on the dyno from a previous tuner also and redline was set to 7100 RPM.

 

I'm not saying it will break but for a reliable setup you need to draw the line somewhere between performance and reliability before adapting the build to to tolerate more reliable performance. Also iginition or fuel cut systems can tend to break arms so try to avoid them unless you have solids at least. Keep in mind solids would only be required on the exhaust side with the Tomei 260 / 270 setup - EDIT Unless you are revving over 7000 RPM then the intake lifters are at risk.

 

Nice setup btw @ 500 rwhp, are you still running VCT?

Edited by Xxx_Ruff_Ryda_xxX

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No VCT as it is an S13 Red top.

 

Did the cams and Turbo in 2004 this may explain the low cam lift some what.

Been running as is with 8000 rev limit with no problems just need to update the combination..

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No VCT as it is an S13 Red top.

 

Did the cams and Turbo in 2004 this may explain the low cam lift some what.

Been running as is with 8000 rev limit with no problems just need to update the combination..

 

I see, yes the lift will factor how it treats the valvetrain. Low duration and high lift cams tend to stress the valvetrain the most but without VCT I wouldn't see why you wouldn't go solids. It's cheap insurance to prevent a broken rocker arm and a potentially damaged cam or worse with the cost of solids, installation unless you DIY and setting the clearances.

 

If you want some form of reasonable response with meaty mid range and good top range at approx 450 rwhp then go the Tomei cams, if you want to slightly sacrifice some bottom and mid for more mid-top then the HKS cams TurbostyleR suggested would work well. Adjustable cam sprockets would give you some good results but it will take at least 2 hours on the dyno more than likely.

 

FYI you won't get much more power with anything after 23.5 PSI on the GT3071R, it runs off the map and surges with choke after that but it can reach 480 hp at the engine is the flow is there so you may still crack 430-440 rwhp on a non-happy dyno. I'd definitely consider a twin scroll setup though if you can.

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Looking around on all other sites as well the 260 in and 270 ex with 12mm lift seem to be the favoured combo..

 

What is the reason for shorter duration on the inlet cam?

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Looking around on all other sites as well the 260 in and 270 ex with 12mm lift seem to be the favoured combo..

 

What is the reason for shorter duration on the inlet cam?

 

 

With 12m lift I wouldn't be revving it to 8 without solid lifters and supporting mods. Another 3mm of movement on your rockers every rpm will create a heap more rocker speed at high revs.

 

I have HKS step 3 264/272 in my redtop, with a gtx3071 although I haven't got it together yet. But the main idea of 264/272 cams is to increase top and mid range while still keeping some response with the smaller inlet cam and also reducing back pressure.

 

Everyone has their own theory on what works and I suppose it all depends what you really want to use the car for.

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Just looking into the solid lifter conversion, do you need to get the rockers machined for the Tomei solid lifters and Camshafts?

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Just looking into the solid lifter conversion, do you need to get the rockers machined for the Tomei solid lifters and Camshafts?

 

I haven't heard of that being a requirement. When you go solids you have to set all your shims correctly and periodically check clearances, but apart from that it's business as usual.

 

Also, avoid getting Titanium retainers; stick with the oem steel ones.

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Anyone have any experience on the cheapest supplier of Tomei parts in Australia or online?

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http://jessestreeter.com/

 

Always gone through Jesse, top bloke and never any problems at all. Also does Yahoo Auctions in Japan if you need anything from there.

 

If you want to stay within Australia there are some dealers on here also but they are usually more expensive.

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Also, avoid getting Titanium retainers; stick with the oem steel ones.

 

Really, is that correct? I've always thought that the OEM ones can break with high pressure springs, especially with 120 lbs...

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Also, avoid getting Titanium retainers; stick with the oem steel ones.

 

Really, is that correct? I've always thought that the OEM ones can break with high pressure springs, especially with 120 lbs...

 

Haven't heard of that happening, but you could be right. The main reason I suggest to avoid them is that folks have had issues before, and the general consensus of the various places queried was that Titanium retainers are really only for low-kilometer race builds. The problem is that the Titanium used isn't as hard as the steel shims, so wear can occur. A sort-of-recent thread on this:

 

http://www.nissansil...owtopic=2444272

 

Steel is plenty strong too; the use of titanium is only to reduce the weight of the valvetrain. Not sure whether you can buy lightweight steel retainers for the SR20, but that would be a good option if they're available.

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Another thought or concern I have is about the valve springs.

I had dual valve sprigs put in when the motor was built in 2004, there is no part number on the invoice.

 

Is there any way of telling if these will bind with 12.5mm lift or should all upgrade springs be suitable.

 

Can I measure any thing while old 9.5mm lift cams are still in place...

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Also, avoid getting Titanium retainers; stick with the oem steel ones.

 

Really, is that correct? I've always thought that the OEM ones can break with high pressure springs, especially with 120 lbs...

 

Haven't heard of that happening, but you could be right. The main reason I suggest to avoid them is that folks have had issues before, and the general consensus of the various places queried was that Titanium retainers are really only for low-kilometer race builds. The problem is that the Titanium used isn't as hard as the steel shims, so wear can occur. A sort-of-recent thread on this:

 

http://www.nissansil...owtopic=2444272

 

Steel is plenty strong too; the use of titanium is only to reduce the weight of the valvetrain. Not sure whether you can buy lightweight steel retainers for the SR20, but that would be a good option if they're available.

 

That's interesting, I would have thought with such spring rates they would be a requirement but if they aren't as strong then it's useless but what's to say bad fitment isn't the issue also.

 

It would vary between manufacturers I'd imagine also.

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Another thought or concern I have is about the valve springs.

I had dual valve sprigs put in when the motor was built in 2004, there is no part number on the invoice.

 

Is there any way of telling if these will bind with 12.5mm lift or should all upgrade springs be suitable.

 

Can I measure any thing while old 9.5mm lift cams are still in place...

 

Well they are dual spring so if one was to bind or break at least you would know and a vavle wouldn't drop but it's still a risk not knowing what they are. Having said that, 12 - 12.5mm is a large lift so if you were to upgrade check out BC or Supertech springs.

 

Dual valve springs for only 9.5mm lift on a high duration cam of 272 :wtf1: ...I don't know who advised your build but you could have kept stock springs on 9.5mm lift. You would have noticed it would have had fairly average power and torque until past 5000 RPM. That would have killed spool times too.

 

I'm still running stock springs on 10.5mm. I would like to update my springs but I'll be changing my setup soon anyway. :teehee:

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Well yes I have said it is not a very good cam option in the engine at the moment.....

I think this is the result of an engine builder paranoid about breaking rockers.... it was 11 years ago and a very light car that has been at 390 rwhp with zero problems mind you.

 

I was more looking for Fully compressed heights of springs

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Well yes I have said it is not a very good cam option in the engine at the moment.....

I think this is the result of an engine builder paranoid about breaking rockers.... it was 11 years ago and a very light car that has been at 390 rwhp with zero problems mind you.

 

I was more looking for Fully compressed heights of springs

 

Of course, don't get me wrong I wasn't emphasising the cam profile deliberately to insult you or your setup but merely astounded at how the builder decided that is an ideal combination and identifying the causes of such cams. It has been reliable which is a good point.

 

Normally SR20DET dual springs will offer a higher spring pressure of 90lb+ but back in 2004 I'unaware of the springs were available then. Exactly what lift it will tolerate reliablly at a given RPM is beyond anyone but the dual spring BC 90lb can take BC 264 12mm cams reliably before the cams run out of puff without bind but perhaps we can get better information from those with first hand experience since mine is based on forums.

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That's interesting, I would have thought with such spring rates they would be a requirement but if they aren't as strong then it's useless but what's to say bad fitment isn't the issue also.

 

It would vary between manufacturers I'd imagine also.

 

I'm far from being an authority on the subject, but in all my research on titanium retainers versus steel (prompted by that thread), I couldn't find any reputable comments to the effect that steel retainers should be replaced with titanium because they lack the strength required. In fact, I don't think I even saw one from a disreputable source lol. I did however find numerous statements to the effect that titanium retainers can wear over time, so the conclusion of that thread seems to be on point.

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Titanium has a higher strength to weight ratio, but steel wins hands down at absolute strength. Specially the high tensile steel engine parts are made from. Titanium also tends to be more brittle than steel. Titanium is not recommend where a part needs to be strong and durable.

 

However for a race engine you where you want to remove mass from the valve train to get a higher redline, it's useful.

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Hmm makes sense, a denser steel retainer should tolerate more than a lighter titanium equivalent.

 

I would much prefer just not stroking a motor but rather boring it out and allowing the high flowing head to rev harder and longer with less hassles about a lower redline instead of worrying about titanium valvesprings in that case.

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Cheers RUFF for putting me onto Jesse Streeter..

 

Got all my parts through him at a great price

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Cheers RUFF for putting me onto Jesse Streeter..

 

Got all my parts through him at a great price

 

No problems mate and all the best with the next build ;)

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