EZ76's car
Evolving Member
Joined: Jul 2003
Posts: 343
Likes: 0
From: San Diego
With the upgraded valve spring kit, what's the safest max RPM to see on a daily basis? 8K? Quantum says 10K rpm on the head with those, but what's safest on the stock bottom end? I'm assuming you can shift much higher up to take advantage of a long gear with those cams while road racing or autox'ing.
We did not do an apples-to-apples comparison with the HKS and that is unfortunate, because although I'd like to give the Pipers credit, I think the headwork might have been equally or more responsible (stage 5++ from Quantum Racing i.e. stage 4 from BJ's).
Put another way, with headwork, I am not sure the cams matter as much, at least on the stock or TME turbos, but this is just theory.
In this cam gear configuration (Piper rally cams, cam gears @ -2/-2) I see about 7 inches of vacuum at idle and it wants to stall a little more but not so much that I'm upset.
Have not mapped 91 octane yet.
As far as redline, yeah the valvetrain might be in a position to handle 9 grand but my understanding is the rod bolts are the more limiting factor so we didn't push it (and of course there's only so much power to be had there anyway with this set-up). It does tick a little more as is, no biggie.
Put another way, with headwork, I am not sure the cams matter as much, at least on the stock or TME turbos, but this is just theory.
In this cam gear configuration (Piper rally cams, cam gears @ -2/-2) I see about 7 inches of vacuum at idle and it wants to stall a little more but not so much that I'm upset.
Have not mapped 91 octane yet.
As far as redline, yeah the valvetrain might be in a position to handle 9 grand but my understanding is the rod bolts are the more limiting factor so we didn't push it (and of course there's only so much power to be had there anyway with this set-up). It does tick a little more as is, no biggie.
Originally Posted by DrMerl
With the upgraded valve spring kit, what's the safest max RPM to see on a daily basis? 8K? Quantum says 10K rpm on the head with those, but what's safest on the stock bottom end? I'm assuming you can shift much higher up to take advantage of a long gear with those cams while road racing or autox'ing.
I still have my rev-limiter still intact, so I don't have to worry about it.
Originally Posted by Smogrunner
Driving impressions?
The spring we're using in the Forge DV is so stiff that there's some minor flutter coming off part throttle in 4th and 5th gear but I think this is a reasonable trade-off of keeping 26psi in the system. The JDM MR diverter valve did not hold more than 24psi consistently.
Originally Posted by ez76
As smooth as the dyno would indicate with one exception - torque comes on so strong now that I consistently lose traction in 1st gear in a straight line. That takes a little getting used to.
Evolved Member
Joined: Aug 2003
Posts: 763
Likes: 0
From: bay area, ca
hmm just look at both ez's and smoggie's graphs shows a pretty gain with the differnet cams. just in case anyone wants to do a lil comparo:
https://www.evolutionm.net/forums/at...chmentid=49685 <- ethans, on pg1 of this thread
https://www.evolutionm.net/forums/at...chmentid=49612 <- toms.
esentially you pay 2gs for the headwork, and about 400 more for the cams to get instant tq and the same hp #s on 100 octane. at least i think thats wut it breaks down to at the simplest way of looking at it, right?
https://www.evolutionm.net/forums/at...chmentid=49685 <- ethans, on pg1 of this thread
https://www.evolutionm.net/forums/at...chmentid=49612 <- toms.
esentially you pay 2gs for the headwork, and about 400 more for the cams to get instant tq and the same hp #s on 100 octane. at least i think thats wut it breaks down to at the simplest way of looking at it, right?
The head and cams were definitely not the biggest bang for the buck mod I've done but given that I'm pretty committed to stock-like spool up and a cat, it was something else to try and I felt better about doing those than an intake manifold upgrade though that could be fun too.
I am kind of curious how a set-up like mine would do on 116 octane and catless but that's not what I drive on daily so if we tried it it would just be for dyno queeny ****s and giggles.
Of course there's other odds and ends to try like the WORKS throttle body, more porting/port matching, and putting the DNP manifold back on (had to take it off and put back the stocker because of leaks - NOT due to a DNP manufacturing defect but rather other stupid problems that were probably my fault).
Also we'll do a proper 91 octane map at some point - real curious how much of that 320lb-ft of torque we'll be able to keep on the crap gas!
Yup, like I said if I could do it again I'd have put off the Pipers until I saw what the ported head did with the HKS cams. With the TME turbo, I have a funny feeling it wouldn't have been substantially different, but now that's for the next guy to try.
I am kind of curious how a set-up like mine would do on 116 octane and catless but that's not what I drive on daily so if we tried it it would just be for dyno queeny ****s and giggles.
Of course there's other odds and ends to try like the WORKS throttle body, more porting/port matching, and putting the DNP manifold back on (had to take it off and put back the stocker because of leaks - NOT due to a DNP manufacturing defect but rather other stupid problems that were probably my fault).
Also we'll do a proper 91 octane map at some point - real curious how much of that 320lb-ft of torque we'll be able to keep on the crap gas!
Originally Posted by leif
esentially you pay 2gs for the headwork, and about 400 more for the cams to get instant tq and the same hp #s on 100 octane. at least i think thats wut it breaks down to at the simplest way of looking at it, right?