Valve Bounce

[r32gtst sedan]

first off is this true i got told that only pushrod motors have valve bounce.

secondly that 7m gte engines are shit cuz they blow head gaskets and corrode out the head

thirdly what sort of limiter do rb25s use ( are all rbs the same) and are neos and r33 rb25 both limited at 7000 or thereabouts

and lastly will a stock rb25 turbo make 300rwhp

Thanks for your help

[FineLine]

first off is this true i got told that only pushrod motors have valve bounce.

secondly that 7m gte engines are shit cuz they blow head gaskets and corrode out the head

thirdly what sort of limiter do rb25s use ( are all rbs the same) and are neos and r33 rb25 both limited at 7000 or thereabouts

and lastly will a stock rb25 turbo make 300rwhp

Thanks for your help

A. No. overhead cam engines can float valves with the best of them

B. No they are not shit, Yes they do have an inherint problem with head gaskets. A set of head studs and a decent gasket and you have a motor as good as the 2j

C.Mine came speed limited, Not rev limited

D.yes

[Fat_Tony]

A. No. overhead cam engines can float valves with the best of them

B. No they are not shit, Yes they do have an inherint problem with head gaskets. A set of head studs and a decent gasket and you have a motor as good as the 2j

C.Mine came speed limited, Not rev limited

D.yes

220rwkw from stock turbo, no way. Suprised about the amount of people who think they can get over 200rwkw on the stocker.

[zebra]

7M's are a much under rated engine....I rate them better than RBs

Any engine can have valve bounce...i get it about 7500 in my car....but it has had a hard life so the springs are soft.

[old mate]

7ms were not torqued correctly from factory. at least thats what i have been told.

[mad082]

220rwkw from stock turbo, no way. Suprised about the amount of people who think they can get over 200rwkw on the stocker.

it can be done. it probably won't last very long but it can be done. most people will tell you that the stock turbo stops making power at about 13psi (because they read it on the internet so it must be true), but i can tell you that is wrong. i have seen it with my own eyes. stock turbo running 16psi made about 20kw more at 16psi than it did at 13psi in back to back runs. so even if you say that the dyno was reading high and ignore the total power figure it made, back to back runs with just enough time between runs to wind the boost up showed a 20kw gain where most people will say that it won't make any extra power or will lose power.

also my tuner has a rb25 in his cerfiro and he is making between 210 and 215kw @12psi on the stock turbo. the reason why i say "between" is because he has had it on his dyno and another workshops dyno (before he got his dyno) and they were both within a few kw of each other.

[PM-R33]

Are you saying 20rwkw? That's a big jump from 13psi to 16psi on the stock turbo man. Your talking around 30-35HP at the engine on something that is allready pushing at its limit. Must have been a freak of an engine/turbo or something.

[FineLine]

220rwkw from stock turbo, no way. Suprised about the amount of people who think they can get over 200rwkw on the stocker.

I didnt say it would last, But yes, you can get it.

[mad082]

Are you saying 20rwkw? That's a big jump from 13psi to 16psi on the stock turbo man. Your talking around 30-35HP at the engine on something that is allready pushing at its limit. Must have been a freak of an engine/turbo or something.

pretty sure it was about 20kw at the wheels. (was over a year ago now, so memory is getting a bit dodgy). but it was certainly up around there somewhere.

[Zardos]

(1) that 7m gte engines are shit cuz they blow head gaskets and corrode out the head

Thanks for your help

The 7m- GTE dose not like big boost on standard motor.

Also they do tend to leak oil a lot more then RB's do.

The main problem is that toyota did not torque down the head enough. Which is why a lot of guys go the metal gasket route and new bolts all round.

7M's are a much under rated engine....I rate them better than RBs

I would not go as far as saying the 7m-GTE is a better engine then the RB

If you have ever pulled apart an old 7m-GTE and seen the oil pump setup on these then you will see why. These engines were designed before the RB25/26.

If you are talking about 1jz-GTE or 2jz-GTE then yes you are correct.

If i had to decided to either buy a 7m-GTE or RB i'll choose the RB , mainly because parts, standard or after market are so easy to get for RB.

[r33_racer]

My road r33 when running with the standard turbo on 12psi had 210rwkws for a couple of years with no problems until i went stupid with the mods....i just cant help myself.

But yes it can be done or close enough.

[StealthX]

RB20DET < 7M-GTE < RB25DET < 1JZ-GTE < RB26DETT < 2JZ-GTE

[RBceffy25]

220rwkw from stock turbo, no way. Suprised about the amount of people who think they can get over 200rwkw on the stocker.

What makes you say that?

Have you tried?

I havnt done this personally but I know a guy who has. form memory He made 302rwhp on S1 RB25DET maxing the shit out of the injectors and running 16-17psi.

I'm not saying its a good thing but yes as it has been stated multiple time, it can be done.

Edited April 30, 2010 by RBceffy25

[RBceffy25]

C.Mine came speed limited, Not rev limited

Very interesting as my ceffy came from japan rev limited not speed limited.

Can anyone shed some light on this?

[Duncan]

they are both rev and speed limited from the factory. 7000rpm and 192klm/h

[r32gtst sedan]

cool thanks for all ur help.

i am doin work exp at honda and thts wat a mechanic there said

[Nee-san]

RB20DET < 7M-GTE < RB25DET < 1JZ-GTE < RB26DETT < 2JZ-GTE

Lol.. that really depends on what series 26 your talking about.

[mad082]

not really. as far as the actual engine goes the 2-jz is a much better/stronger engine than the rb26, and anyone who knows about engines, no matter how much of a nissan fan they are, will say the same. most of the toyota engines are better built than their nissan counterpart.

[Fat_Tony]

Stock does about 130rwkw, I find it hard to belive that Nissan left 90rwkw in the bag for us to unlock.

I had a HKS 2530 that did 220rwkw @ 17psi. Its a bigger turbo than the stocker.

I don't count time-bomb setups as being legitimate power figures. If it isn't bullet-proof its a waste of time.

What makes you say that?

Have you tried?

I havnt done this personally but I know a guy who has. form memory He made 302rwhp on S1 RB25DET maxing the shit out of the injectors and running 16-17psi.

I'm not saying its a good thing but yes as it has been stated multiple time, it can be done.

[RBceffy25]

Stock does about 130rwkw, I find it hard to belive that Nissan left 90rwkw in the bag for us to unlock.

I had a HKS 2530 that did 220rwkw @ 17psi. Its a bigger turbo than the stocker.

I don't count time-bomb setups as being legitimate power figures. If it isn't bullet-proof its a waste of time.

Regardless, he did it and we all saw it.

Of course this wasnt the actual tune he finished with. It was to see what the limits were of the stock gear and as i said everything was at there absolute limit. Yes, there are many variables but on that particular day, on that dyno blah blah blah thats what that particular enging achieved.