Jump to content
SAU Community

Recommended Posts

The answer is a bit rubbery, will depend a little on how big/small spec your turbine and exhaust system is.  The original springs aren't that heavy, and if they've seen a bit of work it's probably time to replace/upgrade. 

Setups will vary, and some will experience float earlier than others if the springs in that car are on the softer end of production tolerances or otherwise tired.

If I was looking to run up over 20psi, springs would be on the shopping list.

  • Like 1

Might be irrelevant but with stock cams and a Hypergear SS2 EWG I was able to squeeze about 25psi into the motor without any valve float on the stock springs. Motor lasted about 1 year of track abuse before it went bang lol.

  • Like 1

It really is a how long is a piece of string questions, basically it all comes down to a lot of things including cams, how far you want to rev it, wear on the springs or even the old was it built on a Wednesday or is it a Friday afternoon special 

  • Like 2

OK, thank you ...

I'm usually not revving the engine highly , it rarely sees 6500 rpm. The limiter is set to 7000 rpm.

The engine has 70k km on the odo, and poncams installed.

I'll take your advice and will run 20PSI for the time being, other than on a dyno how can you tell you get into valve float territory?

 

 

So you are getting float, or don't know and are just chasing info?

 

Probably a bit hard to contemplate playing with the tune without at least giving it a squirt on the rollers to validate what's going on.  You can achieve plenty with road tuning, but an hour of dyno time isn't that expensive and will tell you heaps.

  • Like 1

I was trying to get some information since got a new turbo capable of 24PSI@ 6500rpm which is a big step from the 15PSI of the old turbo.

While being on a roller I found that the power curve went through some strange 'ditches' and I was wondering if that might be due to valve float.

Valve float was not of any concern to me before simply because my old turbo was running less boost.

I'll dial in 20PSI and run more timing to get a good baseline, from there I can work it up should I feel the need.

 

 

 

 

On a serious note however http://www.hypergearturbos.com/index.php?route=product/product&product_id=57
Scroll down. Click dyno results, scroll down and read special consideration for rb25 and it has some info on this for you

Good stuff. Sorry for hi-jacking the thread a bit but can you guys recommend valve springs? Heard supertech are good, are singles enough or should you get dual springs while at it? Retainers aswell or are springs enough?

 

In my case running rb30 (not forged) so revving only 6800 atm. Looking for ~500-550 hp, now at 440hp and 23psi (holset he351) with suspected leaking standard bov

 

 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Brooooo Please send ABS control unit schematic Please! R33 gts25t ABS (Its two plug ecu, black and white) wire colors possible? [email protected]
    • Don't even try to run it on the stock ECU if you're going to have the boost controller bring boost above ~10 psi. I've already told you that. If you use the Nistune ECU, you will need to CAREFULLY read the available documentation for Neo tuning, and read some threads on the Nistune forums, to discover the various things you have to do to prevent the ECU from going bananas when the boost is too high. The is a table associated with th boost sensor that must be modified to prevent it from shitting the bed. This is just one of the things that you will need to do to the tune in Nistune, because the Neo turbo ECU will be expecting to see a number of things (such as the TCS) that are not there, and you have to block the DTCs on those. It is totally not surprising to me that you are having the problems that you are, but the solutions to these problems have been known for >15 years. So just get it done.
    • Hi. Sry iam not a mechanic and iam not at the car atm so i dont know 100% but they told they measure those and even try to change those. AFM they have two. Coils are new a they have my old one too. Plugs too. ECU...we have 25 NEO stock and Nistune 25 NEO.   But i dont know if any one those could be the problem and why/if/what can cause this, Only thing they did not check is fuel...but that walbro 255 is new(like 1,5 years)... That fuel pressure gauge idk...but i let them know Any suggestions?   EDIT: how can they know if it is like you say he ECU pull power when it reaches a specific boost level that is too high? Tha car has boost controler
    • Can you clarify what you mean by boost cut, do you mean it misfires both when under load (driving) and when stationary and out of gear? Or does the ECU pull power when it reaches a specific boost level that is too high (boost control issue)? Does it occur at idle with no throttle? When you say "the ECU is OK", what ECU is it and why do you think it is OK? Have you used the NEO ECU, and if so do you have a MAP sensor attached? Same for the AFM, why do you think it is OK? Do you have any way to put a fuel pressure gauge on it (even just a mechanical one between the fuel filter and fuel rail)?
×
×
  • Create New...