are there any real advantages of an s3 13b over the newer model 13b's or not? i know the only have 2 fuel injectors wich is a disadvantage but i was wonderin what else

 

they seem to last a lot longer, but the s5/4's have bigger ports, lighter rotors, flywheel, higher compression etc etc.

 

here are some of the differences and "my opinions" on if they are better or not ...



S3 has 3 mm apex seals - honestly, i don't care about 2 vs. 3. both have been more than strong enough for the engines i've built.



S5 has 9.7:1 compression vs the 9.4:1 of S3 and S4 - that's an advantage as long as you stay normally aspirated, but it's not something that i would lose sleep over for all but the most extreme racing purposes.



S5 has lighter rotating assembly - advantage again, but again, i wouldn't lose sleep over it.



S4 and S5 have better intakes and 4 injectors - that's an advantage and i think it is worth getting the best one you can find if (and only if you have no intentions) of going with a custom setup like i'm building.



all 3 13B models lend themselves to relatively easy conversion to 4-port motors. you'll just need a decent 12A or 13B-T block to do so.



of course, there is the water seal placement and i've read that the S4/S5 placement in the side housings is an advantage, but i don't really have an opinion.



that's about all i can think of readily.



hope it helps a little.

 

Are they s5/s5 plates really an advantage. I thought that the water seal placement on the s4/s5 was a disadvantage because the water seals are on the plates instead of the rotor housing. Therefore making the lapping procedure an issue because you can only lap s4/s5 plates so many times before they water seal dosn't seal anymore because the grove isn't deep enough?

 

the s4/5 plates have larger ports stock, and are lighter casting, but i like the water seal in the rotor housing....

 

i apologize. i didn't thoroughly proofread what i typed the last time. that was actually supposed to read "disadvantage" for the same reason you pointed out. as i said, i don't really have an opinion on it. i guess it stems from the fact that the motors i build are usually pre-1986 and also i've never had to have an '86+ housing lapped that much.



an interesting thing that i've read about is using the 86+ side housings with pre-86 rotor housings and doubling up on the water seals. it may be worth some research for those of you that want bigger numbers for bragging rights. personally, i don't go for stuff like that simply because the motors i've built up to this point were mainly for the street and i was not willing to try some things just for the possibility of a few more HP.