New 20b manifold
#6
the merge point between the two rear rotors, non equal length, non divided, wastegate dump runner position, etc......
On the plus side, it looks like the turbo is in a decent position and should provide enough clearance for a suitably large exhaust housing (although it's really hard to tell).
Essentially what you're getting is a log-style cast iron manifold made out of tubes instead :-)
On the plus side, it looks like the turbo is in a decent position and should provide enough clearance for a suitably large exhaust housing (although it's really hard to tell).
Essentially what you're getting is a log-style cast iron manifold made out of tubes instead :-)
#7
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i would hazard to say that this is even worse than a plain log manifold. at least w/ a log, all the runners merge into one spot. here the last runner merges directly into the second for whatever reason. to make things even worse the 3rd runner makes 2 count 'em 2, 90deg. turns, one right at the port exit and one where it merges w/ the second runner. and no, gases do not like to make sharp right hand turns. and of all the places to have a 90deg. turn, by god at least don't have it at the port exit, where the exhaust velocity will just slam the exhaust gases right into the wall of the header and right back into the exhaust port. on top of that the diameter of the second runner does not increase after the merge point to accomodate the extra volume of exhaust gas from the 3rd primary. after the merge that one pipe is being fed by two rotors, yet it's diameter stays the same. if you join 2 streams of exhaust, you need double the cross sectional area of the pipe after the junction, or else that'll be a major bottleneck. luckily in this case, there's so many other flaws that, that point shouldn't be too much of a restriction. w/ this design you're equally likely to stuff exhaust back into the motor as you are of evacuating it. i'm not even gonna get into pressure wave tuning.
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#8
Full Member
20B manifold
looks ok to me, looks like the ss hks or the other that I have. I am interested in it, please post contact and price and weight, and what is it made of, and is it coated right now with what?
#9
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I agree with FD racer. It does not appear that there is any benefit to doing it this way that would outweight the trade offs. Why give up easy horsepower. If you go through the trouble of putting a 20b in you might as well maxamize your return.
#11
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It looks like someone has taken a mould of a two rotor design (HKS Maybe?) and added the extra exhaust tubing.
Has anyone designed or made an equal length runner exhaust housing for the 20B for use with a single turbo? I'd love to see photos.
Adler
Has anyone designed or made an equal length runner exhaust housing for the 20B for use with a single turbo? I'd love to see photos.
Adler
#12
Senior Member
Ezio at City performance in Sydney is a master fabricator & has built the most serious 3-rotor exhaust manifold for a 20B conversion on this 92 RX-7. Although its pretty tight in the FD engine bay he has managed to make it a work of art & tuned length as well.
http://www.cityperformance.com.au
An example of his work can be found on that 92 RX-7 in this web site http://www.evil7.com
REgards
http://www.cityperformance.com.au
An example of his work can be found on that 92 RX-7 in this web site http://www.evil7.com
REgards
#14
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Hey guys you guys got me freeked I just bought one of those manifolds adam is working on my car as we speek what is so bad about it. I dont know much about these things is it a bad choice and why?
#15
Formally 20b 3rd gen
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Okay, guy check this website out, www.cityperformancecentre.com look under the fabrications tab..............now that's a manifold
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i hear ya'll.anyone that knows anything about turbos or manifolds would that manifold is purity kraap.and the ones that think it looks aight and fine.i got a webiste for ya.
howstuffworks.com,,check it out.i cant believe a professional shop actually designed that.
oh yes alamo rotary i believe made their own equal length manifold for a t66.
howstuffworks.com,,check it out.i cant believe a professional shop actually designed that.
oh yes alamo rotary i believe made their own equal length manifold for a t66.
#18
Rotor Head Extreme
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Originally posted by 20B 3rd Gen
Okay, guy check this website out, www.cityperformancecentre.com look under the fabrications tab..............now that's a manifold
Okay, guy check this website out, www.cityperformancecentre.com look under the fabrications tab..............now that's a manifold
Looks like intestins to me lol
Edit: I almost forgot! I talked to Adam today and he said that the turbo and manifold he sales is good for 720 rwhp
Last edited by t-von; 07-11-03 at 11:30 PM.
#21
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I respect the constructive critisism for a manifold which has been flowtested and overbuilt to overcome many of the negative concerns. This manifold has been sold to a variety crowd,2 x drag racers etc. The construction is stainless,ceramic coated,but most importantly,the design was to accomodate a T88H in a third gen car without having to sacrafice the a\c,plus,locates the turbo far enough back to account for a true cold air pipe that pulls fresh air from the front air dam.By overkill flow testing,we mean that the crosssectional area of the runners is large enough that the issue of exhaust gas reversion is not an issue.Why did a proffessional shop design a manifold that contradicts many of the obvious fundamentals of manifold design?answer:we are all open for solutions as to how to construct an equal length runner design that will bolt into a 3rd gen and provide room for a cold air pipe!If a customer would like a costom manifold built to highest std. specs,equal length runners etc....walk in the park!
p.s. 586h.p. rear wheels 16lbs.boost more than enough for our Greece customers street car...and $995
he and the 7 others with this piece seem to be real happy! concerns?Call me (Adam)@RX7 Specialties
403 246 6980
p.s. 586h.p. rear wheels 16lbs.boost more than enough for our Greece customers street car...and $995
he and the 7 others with this piece seem to be real happy! concerns?Call me (Adam)@RX7 Specialties
403 246 6980
#22
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wtf is overkill flow testing? this is a joke right? you do know that log style manifolds always flow the best. they evacuate the exhaust gases as quickly as possible through the shortest possible distance. you can't stop reversion w/ larger diameter runners, that's just plain stupid.
#24
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The above post was made by Adam @ RX-7 Specialties using my account.
Here's some pictures of the alamo manifold (very nice but can only fit a very small turbo)
like Adam stated, the shop can design like the alamo manifold. However, the pics i posted are of one made for a t88H in a 3rd gen and built to fit a cold air pipe setup, not a small filter bolted to the compressor.
I suggest calling the shop if you guys have any questions.
Here's some pictures of the alamo manifold (very nice but can only fit a very small turbo)
like Adam stated, the shop can design like the alamo manifold. However, the pics i posted are of one made for a t88H in a 3rd gen and built to fit a cold air pipe setup, not a small filter bolted to the compressor.
I suggest calling the shop if you guys have any questions.
Last edited by Astro; 07-18-03 at 05:56 PM.