setup:
- gsr head w/ stock cams
- itr intake springs
- gsr intake spring on exhaust side
- skunk2 valves

... i was wondering if any of you all-motor gurus out there could help me figure something out... i need to know what is the highest rpm i can set my rev limit to without risking too much damage... i was told 9000 rpm since the stock cams do not generate enough lift to bind the itr springs... i talked to the guy later, but he didnt have spring rates or lift numbers... so i wanna confirm before i up my rev limit... thanks in advance...

 

i think 9000 is as high as you could go, but why? the cams arent going to make power that high so why risk it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Casey &raquo;</TD></TR><TR><TD CLASS="quote">i think 9000 is as high as you could go, but why? the cams arent going to make power that high so why risk it </TD></TR></TABLE>

... is this true for forced induction applications too?... i forgot to mention that this is on a turbo gsr... anyways, i came here to ask my question because you all-motor guys know your shiet when it comes to valvetrain setups, rev limits, and such... anyways, thanks for the info...

 

couldnt tell ya on that one, id guess it probably does. Id still set the rev limit a little lower than that, at like 8700-8800 just in case

 

The turbo is going to determine that more so then the cams. I mean a boosted GSR w/ stock cams can keep making power as high as the 9,500-10,000 range depending on the turbo. What turbo, trim/spec?

 

... i thought that the turbo would allow it to keep making power... but my concern is over-revving the head... so do you think is safe rpm to set as a rev limit with my head setup? 9500 or 10000...

btw, here is the specs of my turbo:
- garrett t3/t04s (t3/60-1)
- .70 a/r compressor housing
- 60 trim compressor wheel
- .63 a/r turbine housing
- 76 trim turbine wheel
- 360* thrust bearing

 

That's a nice size turbo and would make power pretty high. However judging by your current valvetrain set-up I would keep it at 8,500.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mr Milano &raquo;</TD></TR><TR><TD CLASS="quote">That's a nice size turbo and would make power pretty high. However judging by your current valvetrain set-up I would keep it at 8,500.</TD></TR></TABLE>

...8500 huh?... i was thinking that i could at least set the rev limit to the stock type-r rev limit... especially since the cams are less aggressive... hmmm... oh well... thanks for the advice...

 

ive read the ITR valvesprings are actually weaker than GSR, due to the fact that the ITR uses lighter valves, and that means the spring has less to handle. keep the revlimit ~8200, since u wont make power past 7800-8000

 

tell you the truth i wouldnt try to rev past maybe 8500 even though you have itr intake springs and gsr exhaust springs. if you upgraded your spring to some skunks then thats when i would go above 8500 rpm.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">ive read the ITR valvesprings are actually weaker than GSR, due to the fact that the ITR uses lighter valves, and that means the spring has less to handle. keep the revlimit ~8200, since u wont make power past 7800-8000</TD></TR></TABLE>

... sorry but sounds wrong to me... where did you read this?... i think you should check your sources... first off, the valvesprings do not (to my knowledge) support the weight of the valves so the weight should be of little concern... second, spring rate (or stiffness) of the valvesprings is a result of the lift of the cams... and since the itr has more lift than a gsr, the springs are stiffer... it was my understanding that if the itr valvesprings were weaker than the gsr valvesprings, the result would be valve float (at high rpms)... that is why you never use stock valvesprings with aftermarket cams... lastly, with a forced induction application, i think i make power past 8000 rpm... (sorry if this sounds like i am flaming you, i dont mean to, i just hate to see misinformation spread. and if i am wrong, i stand corrected )

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">tell you the truth i wouldnt try to rev past maybe 8500 even though you have itr intake springs and gsr exhaust springs. if you upgraded your spring to some skunks then thats when i would go above 8500 rpm. </TD></TR></TABLE>

... thanks for your input...

... so i've got 9000, 8800, and 2 8500... anyone else (and why)?... i'd like to hear from experience if possible... thanks...

 

the highest i would bring it is to 8800rpm...but no higher then that i know for all motor theres no point cuz those cams wont make power after that...they might not even make power up to 8800rpm...but i dont know about turbo cars

 

You can go the cheaper route, adding only the intake cam. Keeping your stock springs and valves. One reason this works is because the Type-R intake springs are actually slightly *softer* than factory dual intake springs. The reason is Type-R intake valves are lighter than regular intake valves, thus you don't really need additional stiffness from the springs since there is less mass for the springs to control. Type-R intake springs has oval sections which allow about .050"more lift at the valves before coil bind. But yet people who run stock intake springs on R intake cam don't have any problems... why? The problem maybe hidden. 1. with stock springs the valve springs are probably near coil bind, but not quite... so the springs will likely just fatigue a little faster... I would think that if there's coil bind there should be some obvious signs like cam wear or rocker arm wear or something. 2. the valve timing, it is pretty hard to tag the intake valves with the piston because it closes ABDC (after bottom dead center), even if you float a little your chance of valve tag is very little...


this is pulled from a very old site G-speed.net
the actual link is
http://www.g-speed.com/pbh/b16a/#camshafts

enjoy

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8T_EG &raquo;</TD></TR><TR><TD CLASS="quote">

...8500 huh?... i was thinking that i could at least set the rev limit to the stock type-r rev limit... especially since the cams are less aggressive... hmmm... oh well... thanks for the advice...</TD></TR></TABLE>

Hmm. Well the stock ITR redline is 8400 and 8500 is fuel cut I believe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1.8T_EG &raquo;</TD></TR><TR><TD CLASS="quote">

... sorry but sounds wrong to me... where did you read this?... i think you should check your sources... first off, the valvesprings do not (to my knowledge) support the weight of the valves so the weight should be of little concern... second, spring rate (or stiffness) of the valvesprings is a result of the lift of the cams... and since the itr has more lift than a gsr, the springs are stiffer... it was my understanding that if the itr valvesprings were weaker than the gsr valvesprings, the result would be valve float (at high rpms)... that is why you never use stock valvesprings with aftermarket cams... lastly, with a forced induction application, i think i make power past 8000 rpm... (sorry if this sounds like i am flaming you, i dont mean to, i just hate to see misinformation spread. and if i am wrong, i stand corrected )

[QUOTE=1.8T_EG]

... thanks for your input...

... so i've got 9000, 8800, and 2 8500... anyone else (and why)?... i'd like to hear from experience if possible... thanks...
</TD></TR></TABLE>
i was just saying to be on the safe side............