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Redline Increase on stock componets?


Guest Intrinsic
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Guest Intrinsic

Hello all. Is it safe to raise the redline on stock block/valve train componets? If not what is the limiting componet(s) that should be upgraded? Does the 2JZ-GTE powerband continue after 6800rpm or does it fall off?

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Guest Intrinsic

Thanks for the quick reply ;). I have a Turbonetics Super T-72. This turbo came on the car when I bought it. The powerband is so small at my current boost pressure (currently at 1.1 Bar[16.2psi]) due to turbo lag that I would be better off getting a smaller turbo with a sooner spool to increase my usable power band. Just thought that another option would be to increase the redline, therefore increasing my powerband on the high side vers the low side with a smaller turbo. I just dont know if this would be a viable option without having internal engine work or head work or which would be more exspensive. Alot of power potential with a big turbo but not worth it if I do not raise the boost I suppose.

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Do you have other cams ? if you do have 264´s or 272´s then it´s well worth it with a T72

 

i think that it was said that you shouldn´t go over 7500rpm on stock componments. Just upgrade your springs and retainers and get other cams(if you have stock ones)

 

i have the crower springs and retainers, HKS 264 cams and ARP headbolts and the rev limiter is set to 8200rpm

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Guest Intrinsic

So the answer to my first question is: Get better springs and retainers and install 264's or 272's. I sould have less of a power drop off after 6800rpm and will be able to raise my redline to about 8k. Sounds like I have a plan now :eyebrows: . Thank you for your input.

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That's a long way to wind the revs up on a stock bottom end. When your rod bolts let go it'll probably destroy the block.

 

I wouldn't go past 7200rpm purely as that's the VVTi rev limit and the bottom end didn't change to accomodate that. Anything beyond that and the stock rod bolts are the bit that has the reputation for letting go first.

 

-Ian

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That's a long way to wind the revs up on a stock bottom end. When your rod bolts let go it'll probably destroy the block.

 

I wouldn't go past 7200rpm purely as that's the VVTi rev limit and the bottom end didn't change to accomodate that. Anything beyond that and the stock rod bolts are the bit that has the reputation for letting go first.

 

-Ian

 

i don´t have the VVTi and i rev to 8k with the rev limiter set to 8200rpm, Many in the US rev to 8500rpm on stock bottom end and even 8800rpms on stock bottom end

 

for example on supraforums.com

onelove revs it to 8800rpm on the stock bottom end , and pushing 36psi about 1000 hp to the flywheel

 

Supragrl93 also reved for a while to 8800rpm on stock bottom end with 802rwhp, but see recently spun a rod bearing when roadracing and didn´t notice that she hit the rev limiter to much she hit it for 3+ seconds

 

but i´m not at all suggesting that he should rev it to 8800rpm. But if he upgrades the valve springs and retainers and gets HKS 272 cams. He should be safe to 7800rpm

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i don´t have the VVTi and i rev to 8k with the rev limiter set to 8200rpm, Many in the US rev to 8500rpm on stock bottom end and even 8800rpms on stock bottom end

 

for example on supraforums.com

onelove revs it to 8800rpm on the stock bottom end , and pushing 36psi about 1000 hp to the flywheel

 

Supragrl93 also reved for a while to 8800rpm on stock bottom end with 802rwhp, but see recently spun a rod bearing when roadracing and didn´t notice that she hit the rev limiter to much she hit it for 3+ seconds

 

but i´m not at all suggesting that he should rev it to 8800rpm. But if he upgrades the valve springs and retainers and gets HKS 272 cams. He should be safe to 7800rpm

 

I'm afraid I'm not as up on Supraforums as you. I still say that if you want your stock bottom end to last a few years, don't go past 7200rpm. It depends on your definition of "safe". We all know that these bottom ends can take more power than is useful on the street, which is great, but increasing the revs causes such higher loads that it's quite unpredictable when failure will occur. 7200rpm passed Toyota's massive durability tests and without a mahoosive turbo and wide cams you can't use anything beyond that anyway.

 

Why would upgrading the valve springs and retainers make the bottom end safe to 7800rpm? That's top end...

 

-Ian

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I'm afraid I'm not as up on Supraforums as you. I still say that if you want your stock bottom end to last a few years, don't go past 7200rpm. It depends on your definition of "safe". We all know that these bottom ends can take more power than is useful on the street, which is great, but increasing the revs causes such higher loads that it's quite unpredictable when failure will occur. 7200rpm passed Toyota's massive durability tests and without a mahoosive turbo and wide cams you can't use anything beyond that anyway.

 

Why would upgrading the valve springs and retainers make the bottom end safe to 7800rpm? That's top end...

 

-Ian

 

 

i wasn´t sayin that valve springs and retainers would make the bottom end safe to 7800rpm. I was saying it is already safe to 7800rpm. I said he should upgrade his valve springs and retainers before reving to 7800rpm and that he should get HKS 272 cams to get power at the high end of the revs.

 

Ragnar

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Guest Intrinsic
Dosnt the stock engine HP/Torque curve cross at 6kish any way making that the best time to change gear for max hp and tourque? Or am I being a numpty?

 

Yes, on my car once i get aroun 6kish I can feel a decrease in the acceleration (less hp). The reason for this is simple. The duration and height that the cam opens the intake and exhaust valves is to small therefore at these rpm's the lifters are opening and shutting the valves to quickly and doesnt allow the engine to breathe as good. Therefore, a larger cam height and duration will allow the engine to breath better allowing a larger amount of time for the air to enter and exit the cylinders therefore this would shift the powerband further to the right and HP would not drop off until later on in the RPM range. My turbo spools fully to late, at about 5.2k ish or so. At higher gears (ie 3-6th) if I shift at the optimal time it puts me below the turbos fully spooled point. The only way to solve this that I see is to raise my rev limit to extend my band further to the right vs the costly option of getting a smaller turbo. Although at my boost levels I believe I might be better off going with a smaller turbo. As for changing the rev limit, I do not have a rev limiter on my engine currently which is dangerous so I installed an adjustable shift light.

 

Thanks to everyone for giving there inputs. It is very useful. :D

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It sounds to me like you aren't happy with how long your turbo takes to spool, perhaps you should, as you say, consider a smaller one before raising the rev limit? That turbo sounds awful to drive with :( You'll find the car a lot more fun to drive if it's on boost by 4000rpm, which a suprisingly large (T67) turbo can achieve.

 

Also, putting in cams as big as 272s will damage your power when off-boost and low down even further, making the car feel possibly worse to drive under 5200rpm!

 

Consider the cost of the springs, retainers, and a pair of camshafts against a simple turbo swap (if your manifold is a standard T4 flange). You can sell the T72 on ebay to get some money back, but you can't shift stock cams for peanuts :)

 

Having said that, putting in a 256in 264ex or a 264/264 pair will improve the breathing sooooo much above about 5500rpm where the stockers really choke up. But at stock rev limits this setup doesn't need any changes to the springs or retainers. And your low down power is affected so little it's unnoticeable when driving.

 

As to the stock motor being safe at 7800rpm, mmmm. I have my doubts. If ever there was a move that was "asking for trouble" with the extremely tough 2JZ, it's upping the rev limit. Your mileage may vary, I know someone running to 7500rpm merrily and the engine has been singled-up for over 5 years now. But each 100rpm increment increases the chance of something letting go and the wear factors by an exponential amount.

 

Oh and with a 256/264 setup and a T67 I still found a power falloff above 6800rpm when I upped my limit to 7200. So I put it back to 6800 seeing as it was pointless putting the extra stress on the engine.

 

-Ian

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Sorry to sound dense, but how do you increase the redline? I'm sure you don't simply tippex over the red line on the revcounter do you?

 

No, you use a rubber :)

 

To raise the rev limit, you need any one of these:

A blank fully mappable aftermarket ECU

A ferkled stock ECU like a Blitz unit

An E-Manage Ultimate and someone with a clue

 

-Ian

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