I think I've decided against the ssautochrome stainless jobbie, since some people have had issues with them. I've found the HKS FD mani, but not for the FC. Anybody?

HKS doesn't make an SS manifold for the fc. It only makes a cast one. The one from ssautochrome is new. The one everyone has had problems with was meant for the 3rd gen.

I'm fine with a cast one. I heard it can take the heat better than stainless.



Nevertheless...

Anybody have something good to say about the ssautochrome one for the FC?

you can always try asking one of the members in japan to pick a used one up

Does it matter that the ssautochrome mani is not divided? Is the HKS cast mani divided? I'm guessing not?



What are the benefits of divided vs. undivided?

Does anybody have a picture of this HKS mani?



17141-121188 MAZDA RX-7 1987-1991 Turbo ; Engine Code: 13BT TO4 Internal $340.00

Now for my third attempt at this(keep getting interupted). Divided manifolds flow better producing faster spool and have less restrictions than cast manifolds. The HKS cast manifold isn't divided. I believe the ssautochrome manifold is divided but I don't thinkit is equal length.

just wait til 9base3 gets done fabricating a manifold

HKS manifoldssautochrome manifold

Niether manifold is divided, but the ssautochrome offers the ability to use an external wastegate for better boost control and is cheaper. I found the HKS one at the "evil store".net and the ssautochrome one on ebaymotors.

What's the diff. between "standard" wastegate and "external" wastegate? I'm presuming "internal" means it's built into the mani, because the price is so much higher. If the cast HKS mani has no provision for an external wastegate, and doesn't include one, how is boost controlled? With a wastegate built into the turbo like the TII stocker? https://www.nopistons.com/forums/pub...1047683561.gif

Internal wastegate is exactly what is on the stock TII turbo and is built into the turbo(not the manifold). An external wastegate is one that is separate from the turbo that you'll have to buy yourself and connects to the manifold on it's own separate pipe. An external wastegate offers more control and doesn't have too many problems with spiking like an internal wastegate. An internal wastegate is basically inferior to an external wastegate.

Man, you guys got it all wrong.



HKS sells BOTH a non-divided and a divided cast manifold thats universal to both the FC and FD. Both are available in external and standard wastegate configuration. HKS also sells stainless tubular manifolds (fully divided) for BOTH the FC and FD. wether there the same part I don't know. The most common ones you'll see in the states are the stainless tubular for the FD and the cast non divided. You will have to special order any of the other ones from Japan (fully divided cast, and tubular for FC).



Divided is always the way to go, you gain spool speed and have better top end. (assuming your running a divided turbine housing also). The HKS cast non divided is a "log" style and will not flow as much and will spool your turbo slower, but this system still works fairly well (with a non divided turbine housing). The SSAutoChrome FC manifold is modeled after the HKS cast, its horrible for flow dynamics, but again, will work and is dirt cheap like the HKS cast. The SSAutoChrome FD manifold (or the OBX, same dimensions / design) will NOT fit the FC unless you mod it or use the less flowing on-center type turbine housing. (the FD manifold is fully divided). Theres some fitment issues even on the FD if running larger sized turbos. The section were the tubing goes from round to square for the T4 ports section is a HORRIBLE merge.



I have YET to see a truly equal length manifold from ANY of the big manufactures (HKS, GReedy, A'pexi, Panspeed etc). All of them are near equal length or really diffrernt, but not totally equal. Even though there not totally equal, there benefit over the log style or merged manifolds are still well worth it. your gonna have to build your own, or have one custom made for a equal length jobby.



"standard wastegate" (aka internal) refers to the wastegate being built into the turbo's turbine housing (flapper type). NOT THE MANIFOLD. External wategates are waste gates that bolt to the manifold. The hp levels that single turbos on rx-7's require a external wastegate. the only kit I'm aware of for any rx-7 that uses the internal gate is the older FC HKS T04E sport turbo kit. Most of the more modern turbo's use external gates now.



~Mike................

Mike thanks for helping me. I was just trying to explain it the best I could. I'm not the most knowledgable person in this area. Coulsd you please post some pics of the hks tubular manifold for the FC 86-88 and 89-91? I'm very interested in seeing these. I've only seen the cast divided and non divided manifolds(forgot about this one when searching).

I'm going to take a stab at this...



How do people even notice (or do they?) the difference?



9 out of 10 people running single turbos don't even use the turbo in it's efficiency range, let alone get anywhere near needing to worry about what manifold flows better no?



Maybe I'm WAY off, but my guess is that most of these setups are going to be VERY similar at the street driven levels regardless of the divided/undivided, equal legnth/non-equal legnth design. I seriously doubt that spool time degradation between a cast, log style manifold and a SS tubular manifold would even be an issue with most street cars. PLEASE correct me if I am wrong, this is in NO WAY an argument.



I mean, honestly.. Is the pull different? Is the lag difference REALLY noticable? Or is this just nit-picking? I've rode in so many powerful single cars, I just can't imagine there really being a benefit to either..I didn't feel it.. Most drivers compensate for a cars different driving characteristics anyway correct?



Has anyone ever done testing? ONE CAR. 2 different setups. Are the differences logged? What ARE the differences? Has someone run a single setup with the following and RECORDED data differences?:



Divided TO4S/Stock motor/tubular, divided manifold/14 PSI

Undivided TO4S/Stock Motor/Tubular, divided manifold/14 PSI

Undivided TO4S/Stock Motor/Log, cast manifold/14 PSI



I'd be VERY interested to see that. I always hear the scientific explanation from all the physics gurus on which ones are better, but am confused as to why (if they are better) they even sell the different designs if one is so superior.. other than price of course..



Post ANY data if available. I'd really like to reference it from time to time. https://www.nopistons.com/forums/pub...IR#>/smile.png.

yes, my ss manifold is equal length I don't see how they couldn't make it equal..unless they were monkies here is a pic of an hks ss manifold https://www.nopistons.com/forums/index.php?...topic=29747&hl=

Unless you are **** like me or running the thing on a track where every hp and split second count 5% or 10% better flow really don't matter..

I can get you either the internal or the external TO4 manifold from HKS, PM me for a price on either one. I've never seen the SS tubular ones for a '86+ FC ...but I don't live in Japan either, so that may be the problem.





Also, yes..divided does show a difference, especially in very large hotside turbos..I have no data to post up, but I have graphs/datalogs of undivided T88 and divided T88 turbines spooling, and the divided was 400RPM quicker...this is important for a dragster...





and you can always spray a shot of N2O if you REALLY want to spool quick https://www.nopistons.com/forums/pub...#>/biggrin.png

I don't have any pics of the manifolds, do a search on the evil forum and your bound to find some.



All the HKS tubular manifolds I have seen are NOT 100% equal length. The rear runner tends to be slightly longer. I'm nit picking here, the small difference is not going to be felt nor seen on a dyno.



As far as the LOG manifold compaired to a well designed divided manifold, the results are huge. A 300 rpm difference can be seen just with the non equal cast divided verses the log. I have no absolute dyno proof of the same exact set up with two different style manifolds, but others dyno's speak for them selves. A perfect example is CARx7, hes running a BIG damn compressor and a medium turbine A/R and hes seeing full boost before 4k. I can almost guarentee if he switch to a logger and open valute turbine you'd see near 900 rpm differance. There is some hardcore proof of the split pulse verses collected in the evil forum (early F1 developement with BMW experimenting with split pulse, car was a dog with merged maqnifold)... do a search there. Also, all the big boys that drag race run the split pulse manifolds and turbines to spool the massive compressors. Lisa Kubo's drag civic (3 years ago) ran a split pulse and without it, she wasn't able to spool the turbo early enough to be competitive. Must work, she was the worlds fastest unibody Honda at the time (2000-2001?). the AEBS Focus ran a split pulse on there T61. I can go on and on..... the jist of it is its not a myth or hype, theres a noticable difference. Its up to the car owner wether or not 400-900 rpm quicker spool is worth the extra money or not.





~Mike....................

Mike,



Thanks for the input. I understand completely where the difference is noticable in race applications... I was just curious as to why street guys make such a big deal about the differences in the setups when hardly any of them even go outside the levels of the stock map sensor.. I'd think the benefits of the highher flowing setups would be minimal in streetcars.. I could be wrong though.



My TO4R is .96 and undivided. The manni is SS tubular, not quite equal legnth but is divided. I'm running 7psi and can hardly control the car. I can't even imagine improving on it. Maybe I'll start swapping parts and see if I notice the differences..



Thanks again for the input. https://www.nopistons.com/forums/pub...IR#>/bigok.gif

I agree somewhat. For the street and one who is budget minded the cast logger and .96 works great. But thos not neccesarily looking for huge top end gains, but better response, the divided is the way to go. Its double fold, not only to you gain top end, but you gain spool. Use it either way you wish.... take advantage of the better top end by going larger A/R, or gain response over the non divided without loosing top end, its just a better way to do it period. If you have the money.





~Mike..............