Rb25Det Valve Springs?

[ricardo.benin]

Hi I have a series 1 rb25det cylinder head and I was wondering if just upgrading springs and cam and reusing stock retainers will be ok for 500hp as a street car. I am new to these engines so any info would be great.

Thanks

Richard

[Ben C34]

Stock cam and springs are ok for that power.

Have a look at the rb25 dyno results thread to compare results.

Depends also on what cams you buy. The Tomei Poncams don't require upgraded springs for example.

Edited October 16, 2014 by Ben C34

[GTSBoy]

Also....500HP as measured by what method? Engine? Chassis dyno? US? Australia? UK? EU?

Reason I ask, is that changing cams is not necessary for 500 engine HP, and most of the off the shelf cams that people usually look at are not the bst choices if you are going to change cams. There have been recent threads on here where this has been thrashed through a lot. I suggest that you read.

[GH05T]

not a bad idea if you already have a head which is off the engine though if the cam selection suits the rest of the build

[ricardo.benin]

Hi the head is pulled off as I am rebuilding the engine. But I want to have 500rwhp U.S. measurement. But the only reason that I was even going to replace the springs is I was told that I could get a floating valve spring which I do not want. Btw should I keep the hydraulic lifters or upgrade them to solid lifters basically can I get away without them. Anyways I will do some more reading.

Thanks

[skylinecouple]

When I put my Poncams in I also replaced the springs with the recommended Tomei springs. I can't say what performance difference they made as the cams would account for the extra power but the car revs clean to reline. really, if you think about it, most standard springs have been working pretty hard for quite a few years. If the head is off why not replace the springs for a few hundred dollars and know you have done things right.

My power is up and torque is coming in much lower so definitely add the cams. Springs are insurance to maximize cams.

[ricardo.benin]

Hi Skylinecouple did you replace retainers.

Thanks

[GH05T]

also interested as the main question was not to replace the spring or not but to keep the stock retainers or not.