Dom_C

ok well i just picked up my first FB. It's sweet! anyhow. i've owned a few FC's and for the most part know what i am doing. anyhow i have a few questions. Can i swap over my s4 or s5 intake manifolds on to the s3? i know they should bolt up but i don't beleive the s3 has secondary injectors? and also, does the s3 have a throttle position sensor. if it does will it bolt up to the s4 or s5 tb, or will an s4 tps work? thanks i have searched but didn't find much. all i find is s4 engine swaps. any help would be great. thanks
Dom

Dom_C

bump

speckamp

There are some minor fitment issues w/ the s4+s5 manifolds vs the s3 block. The EGR ports are differently placed, ect....but for the most part they should line up. The ports on the later model manifolds are much larger than the s3 engine, so you can decide what to do there, either fill and smooth the manifold runners, try and portmatch the motor or do nothing.

No, the s3 does not have staged injection, it only has 1 pair of injectors located in the center housing. You can get plugs from Mazdatrix/racingbeat to fill the auxillary injector holes if you like.

The s3 does have a short-range tps, much like the short range tps on the later intake manifolds, a wiring adapter should be all that is needed to adapt the s3 ecu to the s4 or s5 tps (make sure you use the short range tps not the full range tps, the ecu expects wot early and relys mostly on the AFM for load sensing)

Linky:
This is a link to a page showing various 2nd gen intake manifolds vs eachother and a gsl-se gasket

http://www.winisp.net/gsl%2Dse/intake_manifolds.htm

I'm actually in the process of getting the parts together to put the s5 VDI manifolds on my s3....I think it'll be quite amusing to see how the s3 reacts to the vdi manifold...take pics and post them if you beat me to it!

--matt

Dom_C

thanks for all the info. I think i will end up putting s5 stuff on there so that i can have the vdi. i have already converted my s4 to s5 mani's. i think the s3 will like it. . but this wont happen till after i rebuild and port the motor, it's nice to know that i can use those mani's and stuff though. any more info would be great. thanks
Dom

speckamp

Well, it'll be a few months at least since the car's in storage at the moment. I'm going to be controlling the VDI and 6-ports via a MegaSquirt ECU, so I'm not to worried about engagement of them, you might have to get a MSD (or similar) RPM swtich to activate the ports. The S3 uses exhaust backpressure to engage the 6-port system so it's incompatible with the S5 triggering. You will need to retain your air pump if you want the VDI and 6-port system to work as pressure from the air pump actually opens the ports/vdi valve.

Other than that, you'll probably need at least an EGR block off plate (which isn't really an issue as only California models of the S1-3 had EGR systems (iirc)), you might need to eliminate the ACV as well unless you're running a cat which needs the fresh air supply, but you might be able to rig something with some heater hose to bypass the ACV and supply the cat.

From what I can tell from the pictures, the S5 manifold should bolt up and cover all the nessicary ports (including the squareport in the S3 center iron) with little modification.

Also, welcome to the world of the FB's, they're wonderful little cars -- quite capable and full of personality. Personally I find the FB the most desirable RX-7 of the bunch, trailed only slightly by the FD -- tho in my opinion the FB is the most purist Sports/Grand Touring car of the RX-7's. I think you'll love it compared to the FC -- if a pure sports/gt car is what you're looking for.

(I subscribe to the old school definitions of sports / grand touring cars, just for clarification)

--matt

Dom_C

yea right now on my fc i havve the VDI opening with an electric airpump hooked to a toggle switch until i get an rpm switch. And i have removed my aux port system due to the streetport style that i have. (secondaries and auxilories combined into one large port) I already love this little car. i can tell it's going to be alot of fun. Any more help would be great. thanks
Dom

Manntis

Welcome to the SE club