got a d16 boosted at about 14psi! it has stock valvetrain and stock rev limit at the moment just wondered is it worth upgrading the valves, springs or retainers? I dont even know if i can raise the rev limit or if its even worth it! any help would be appreciated! been searching but it doesnt seem to work properly!

 

What rods are you using?

I've found out that it's not only horsepower that makes rods give out, but excessive rpms too.

I've been planning on doing a fully built turbo Z6 myself. Just a little poor at the moment.

 

using eagle rods at the moment!

 

If you have a cam that will make power at higher rpms it would be worth it. It also it might help at the track if you need to launch higher or shift higher (I know it would help my 60fts and ETs if I had an extra 1,000 rpms to play with).

 

so do you think they are worth upgrading with stock cam? or say maybe just buy some better retainers?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Everyones Hero &raquo;</TD></TR><TR><TD CLASS="quote">I've found out that it's not only horsepower that makes rods give out, but excessive rpms too.</TD></TR></TABLE>

Power (torque) is compressive load. RPMs are tensile. Different things.

D16 rods with the lightweight D16 slugs rev to 8500 with reliability, they can handle those tensile loads.

Now, if you select the correct camshaft/valvetrain to move your target powerband up high enough to use that, you can make the same or better power than you do now with less compressive loading. The rod doesn't get as much of a load every engine cycle, but it makes lots more cycles per minute.

You also up your knock limit doing this, since you aren't stuffing as much air charge into the chamber, every cycle, to make the same power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integracivic94 &raquo;</TD></TR><TR><TD CLASS="quote">so do you think they are worth upgrading with stock cam? or say maybe just buy some better retainers?</TD></TR></TABLE>

I don't see a need to upgrade if your keeping the stock cam.

 

IMO if you want to raise the redline and keep the stock cam, go for it. You will be able to redline higher but more safe. And later if you need to upgrade the cam. Just giving you more room to play with.

 

the stock cam runs out of rpm quick. if you going to upgrade your springs and retainers, get a cam that can utilize the new rev limit.

also make sure you turbo still produces power at the added rpm limit.

platinum.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by platinum00 &raquo;</TD></TR><TR><TD CLASS="quote">. if you going to upgrade your springs and retainers, get a cam that can utilize the new rev limit.

also make sure you turbo still produces power at the added rpm limit.

platinum.</TD></TR></TABLE>


very solid advice.

 

im running 16spi on my y8 and i did a full rebuild and just put in stock valves and valve seals... does fine... i got lower compression wiseco pistons and eagle i-beams.... no problems...

oh yeah, im still running the stock cam though.

 

so if i keep the valvetrain stock! could i raise the rpm limit at all? even if its only a little! i gotta a lightened flywheel in there and i removed the p/s and its revving so quick and its got me thinking i could do with a raised rpm limiit!

 

Revving so quick != making power at a higher rpm.

Most of the autocross boys run 500 rpms over stock redline, for the same reason Hyundaidata raises the revlimit of the EP3 with their stock reflash... they can't claim any more (peak) horsepower, it even starts dropping off a bit, but it gives a broader area under the power curve between shifts and drops a full second off 0-60 times. If *you* think this is the case, you can give it a try and see what it does to your real world performance... if it does nothing, then don't do it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">Revving so quick != making power at a higher rpm.

Most of the autocross boys run 500 rpms over stock redline, for the same reason Hyundaidata raises the revlimit of the EP3 with their stock reflash... they can't claim any more (peak) horsepower, it even starts dropping off a bit, but it gives a broader area under the power curve between shifts and drops a full second off 0-60 times. If *you* think this is the case, you can give it a try and see what it does to your real world performance... if it does nothing, then don't do it.</TD></TR></TABLE>

Is that what they say raising the limit does or is that personal experience or something you've heard from another member?

Companies say things all the time, but it doesn't make it true. I'd believe it if it were from your personal experience or another member's personal experience.

 

well i hope to get hondata s300 soon so im guessing i can raise it and try it if not i can just set it back stock and carry on as normal til i can afford the other bits like cams and valvetrain etc

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Everyones Hero &raquo;</TD></TR><TR><TD CLASS="quote">Is that what they say raising the limit does or is that personal experience or something you've heard from another member?</TD></TR></TABLE>

I know a couple of 84-87 CRX guys with Webers, and that is what they do. I can not remember off the top of my head if they have mild cams or not in their class - I'm 85% sure they do - but the rationale is that the OEM designs things for an extra margin of safety, which the auto-x guys cut into. It is my understanding that a number of other guys with other makes of cars do the same.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Everyones Hero &raquo;</TD></TR><TR><TD CLASS="quote">Companies say things all the time, but it doesn't make it true. I'd believe it if it were from your personal experience or another member's personal experience.</TD></TR></TABLE>

Much as I mock Hondata by calling them Hyundaidata - little bit of pgmfi.org rivalry there - having met Doug, who parades around these parts as "Hondata," and his #1 employee and front man Matt aka "Spunkster," I would stake my reputation that it's the truth. I've picked a few little errors out of Doug's logic in my time - not being meticulous enough in re the nature of Honduh MAP sensors (admittedly a cosmetic difference), or neglecting to mention (or, possibly at that time be aware of, or maybe not interested in cluing me in) the fact that OEM RSX intank FPRs are puling piles of substandard **** when combined with Walbro 255 + large injectors - when he tells you that he actually measured 0-60 time increases, provides one of several thousand dyno charts that he's generated on Shawn Church's DynaPack with cutesy little lines drawn @ the rpm you fall back to when you shift gears vs where rpms fall to with stock revlimit, and that gearing easily doublechecked... well, yeah, I'm pretty sure he's correct. Dougie is a pretty smart guy, and doesn't intentionally lie or make up claims, even if he doesn't goddamn swear enough to be trusted. Those Kiwis and their sins of omission...

 

Thanks J Davis. I wasn't doubting you at all, just making sure it wasn't more of that all-too-often advice you find on HT.

Guy A tells Guy B that putting underwear across the front of his bumper will give him a better top speed because there's less air going through the bumper making it more aerodynamic.

Guy B then runs around HT telling everyone and their brother that underwear across the front of the bumper will make your car go to 200mph in under 10 seconds becuase it's aerodynamic.

Next thing you know you have guys asking "What's better? The JDM carbon fiber underwear from jdmshit.com or ebay?"

Once I have an opportunity to do some serious datalogging and tuning I may raise my rev limit to see what it does. As of right now I'm running a lower than stock fuel cut because I'm boosted and don't have a great tune.

 

Nah, I understood where you were coming from completely. Thank you for actually wanting to KNOW. Most people just want an answer that sounds good.