FMAX manifold, comments/better than revhard?
 

i'm in the process of putting together a kit and i ran across a good deal on a Fmax manifold. a friend of mine recommend me not to go for it cuz he says its too restrictive and i guess on another guy's car he has seen it on, doesnt exactly fit rite and the bolts keep coming loose. he tells me revhard is better. i dunno if he meant restrictive cuz the downpipe i know is only like 2.25" and has that recirculation of wastegate gas, but this person has the downpipe w/o the recirculation, but that is no concern cuz i am going with a different downpipe anyhow. and yet another friend tells me Fmax is the best manifold. i had thought Fmax was prolly the best manifold out of Fmax/drag/revhard. anyone want to share their comments on this? i plan to run 15-20psi on track only, 8psi at street if it does see street. this is temporary until i go tubular and build the motor. all comments are welcome, still tryin to learn http://images.zeroforum.com/smile/emsmile.gif

also, anyone know if i get this, will either arturbo's 3" DP or max rev's DP work on this manifold? thanks!!

leo

Re: FMAX manifold, comments/better than revhard? (ITRinEJ)
 

Fmax manfiold isnt that great. I had one on my car and it kept on breaking the studs. The screws kept on coming off. I would go with a revhard mani. As far as restrictive. Most cast iron non-tubular are strictive. Spend about the same amt of money and get yourself a TRR tubular manifold. It cost around 450 or so. A revhard or fmax will cost around the same, last time i checked

Re: FMAX manifold, comments/better than revhard? (ekb18c)
 

Why dont you take a look at the max-rev manifold, a little cheaper than fmax or revhard and much stronger and durable.

Re: FMAX manifold, comments/better than revhard? (ekb18c)
 

where can find some pics of the trr manifold??

Re: FMAX manifold, comments/better than revhard? (98hx99b18c)
 

i have been looking into max rev before, but having known a friend of mine who has used theirs before and seeing that one crack constantly i was not so sure about them, hence i was looking into a cast iron one that will not crack such as revhard. but i may take a shot at max rev after all since geoff does stand behind his product so much, mite as well give it a shot huh? http://images.zeroforum.com/smile/emhammer.gif

Re: FMAX manifold, comments/better than revhard? (ITRinEJ)
 

I love my Fmax manifold.

Re: FMAX manifold, comments/better than revhard? (Reverend)
 

I've seen several f-max's work well... there's a 12.6@120-something crx here in town that uses an f-max with a z-dyne and 60 trim 4/3 hybrid.

Car's alot faster than that, but has major traction issues and the driver lacks "testicular fortitude" as far as I can tell. CRX is being parted out, BTW. Built LS/VTEC. Small intercooler... etc. He's taking almost nothing for the parts, let me knowand I'll ask if anyone needs anything.

Also a full weight SOHC LX Accord with 8 PSI running WAY wrong went 14.60 as well. Had a decent sized t3 take him to that number. Car ran better with the check engine light on. WTF? http://images.zeroforum.com/smile/emsmile.gif Needed MORE FUEL! http://images.zeroforum.com/smile/emwink.gif


[Modified by SiR Kid, 12:49 PM 11/26/2001]

Re: FMAX manifold, comments/better than revhard? (ekb18c)
 

How can the manifold break studs?

Re: FMAX manifold, comments/better than revhard? (Davep)
 

i heard that on the revhard manifold u have to like bend the oil dip stick. is that true?

Re: FMAX manifold, comments/better than revhard? (ITRinEJ)
 

a RevHard manifold will crack....mine has

Re: FMAX manifold, comments/better than revhard? (TurboTypeR98)
 

i heard that before too.

Re: FMAX manifold, comments/better than revhard? (TurboTypeR98)
 

I dont know whether u have the old one or the new one but Arturbo has the old one and his cracked in the top middle.. Although my manifold is the new one and you can see that they strengthened the center section so i guess the new ones are stronger..

Re: FMAX manifold, comments/better than revhard? (TurboTypeR98)
 

DIRep972 is correct. The older rev hards came didnt have extra cast iron to support it, but the newer ones do. I have the old style and mine cracked.

art

Re: FMAX manifold, comments/better than revhard? (Arturbo)
 

after your crack a manifold do you go and get it rewelded or you have to buy a brand new one? Also does the new Rev Hard manifold have the same turbo and down pipe position as the older ones? Since I have the older one and mine cracked and wanted to get the newer one would I need to do any modifications to my down pipe or te compressor position?


[Modified by Mikex25, 7:29 AM 11/27/2001]

Re: FMAX manifold, comments/better than revhard? (Mikex25)
 

the new manifold is the same with the exception of the extra strengthening.. The downpipe will fit fine.

answer to "why can the manifold break studs"
 

I am in no way an expert on this subject, but I have read Corky Bell's "Maximum Boost" (a must read for anyone serious about going turbo, about $25 online) and he says that the thermal expansion of the mounting flange of the manifold is greater then the thermal expansion of the head, and if the outer holes are not enlarged to accomodate the difference, the studs will get sheared right off. This is because the manifold is much hotter (> 1300 F), whereas the head is relatively cool (prolly around 250-300 F on the exhaust side, remember, the head has water in it to carry all that heat away), so you have a rather large difference. And thermal expansion forces are very, very strong; so a 8mm stud is no match.

One way to alleviate the breakage is to enlarge the outer bolt holes, or cut the large mounting flange into 4 (for a 4 cylinder), individual flanges.

Again, I am no expert, but it does seem to make sense to me.

Out and I hope it helped.

Adrian R
'93 del Sol w/ '95 GS-R swap. Awaiting finances to push 15 psi on forged rods and pistons...

Re: answer to "why can the manifold break studs" (dohcsideracer)
 

The F-Max has individual ports for the manifold, which are cut and separated. Also, the bolt holes are cut and it allows for expansion in all angles. F-Max for the street would be my choice. Period.

It's a LOG, and flows like ass, but just turn up the boost 2 more PSI to accommodate it http://images.zeroforum.com/smile/emwink.gif

Re: answer to "why can the manifold break studs" (dohcsideracer)
 

Oh, that way. Yeah, I don't think you see that happen with the fmax manifolds. They have expansion slots cut into them and the mounting holes are liberally sized.