S3 vs S4 13B engine...
#1
Right near Malloy
Thread Starter
iTrader: (28)
Join Date: Dec 1999
Location: Behind a workbench, repairing FC Electronics.
Posts: 7,840
Received 509 Likes
on
345 Posts
S3 vs S4 13B engine...
What are the diffs between the two.
Short block only, as manifolds, ignition systems and, etc are interchangable.
S3:
3mm Apex seal
Waterjacket o-ring location is on aluminium housings
S4:
2mm Apex seal
Waterjacket o-ring location is on iron housings
What else?
Are the 3mm apex's really better than the 2mm? Better handling of PSI for boosted applications, but more damage to the rotor housings.
Does the waterjacket o-ring location really matter? Does anyone even lap irons anymore? You lose the nitride coating when you do that.
Short block only, as manifolds, ignition systems and, etc are interchangable.
S3:
3mm Apex seal
Waterjacket o-ring location is on aluminium housings
S4:
2mm Apex seal
Waterjacket o-ring location is on iron housings
What else?
Are the 3mm apex's really better than the 2mm? Better handling of PSI for boosted applications, but more damage to the rotor housings.
Does the waterjacket o-ring location really matter? Does anyone even lap irons anymore? You lose the nitride coating when you do that.
#2
Moderator
iTrader: (3)
the manifolds are interchangable on engines, but the upper and lower bolt patterns are slightly different. the S3 used a distributor with its primitive EFI, the S4 used the crank angle sensor with it's improved EFI. much better in my opinion ...
2 mm vs. 3 mm - do you really want to start that argument here? i think it's a mtter of how far you want to go and how dedicated (pronounced "****") you are about getting there. i'll leave it there.
otherwise, as far as i know, the only major difference with the engine itself is what you mentioned - the water seal locations.
2 mm vs. 3 mm - do you really want to start that argument here? i think it's a mtter of how far you want to go and how dedicated (pronounced "****") you are about getting there. i'll leave it there.
otherwise, as far as i know, the only major difference with the engine itself is what you mentioned - the water seal locations.
#3
Super Moderator
iTrader: (3)
Also the S4 NA engines have diffusers in the exhaust ports. Quiets it down a bit, but will probably hurt flow. You can grind them out (lot of work) or replace with T2 exhaust sleeves.
The S4 also has lighter rotors and a lighter flywheel. The 3mm vs. 2mm seals doesn't really matter. The 2mm can hold plenty of boost . The 3mm isn't really an advantage.
The other main difference is the location of the coolant seals as already mentioned. I am not sure if there is an advantage to one way or the other. It does seem that the 2nd/3rd gens have more problems with coolant seals, but that may just be because there are more of them around and have to deal with higher engine bay temps. I do believe the RX-8 went back to having the seals in the rotor housings, so maybe that is the better design afterall.
The S4 engine would probably be easier to find and you probably could get one cheaper becuase there are so many more of them compared to the S3 13Bs.
The S4 also has lighter rotors and a lighter flywheel. The 3mm vs. 2mm seals doesn't really matter. The 2mm can hold plenty of boost . The 3mm isn't really an advantage.
The other main difference is the location of the coolant seals as already mentioned. I am not sure if there is an advantage to one way or the other. It does seem that the 2nd/3rd gens have more problems with coolant seals, but that may just be because there are more of them around and have to deal with higher engine bay temps. I do believe the RX-8 went back to having the seals in the rotor housings, so maybe that is the better design afterall.
The S4 engine would probably be easier to find and you probably could get one cheaper becuase there are so many more of them compared to the S3 13Bs.
#4
Moderator
iTrader: (3)
Originally Posted by gsl-se addict
Also the S4 NA engines have diffusers in the exhaust ports. Quiets it down a bit, but will probably hurt flow. You can grind them out (lot of work) or replace with T2 exhaust sleeves.
#5
Right near Malloy
Thread Starter
iTrader: (28)
Join Date: Dec 1999
Location: Behind a workbench, repairing FC Electronics.
Posts: 7,840
Received 509 Likes
on
345 Posts
Well, add to the oppourtunities of engines I can get, an S5 N/A... Just pulled in a wrecker... Front end damage crushed the coils and battery, but engine looks good. Once I get a little SawzAll action going on, I'll check out the engine.
S5's were similar to S4's except they have electric OMP (Which I do not like.) Lighter rotors/higher compression... What else?
S3 engine is free, High mileage core (Close to 200K, still running.). Inexchange for helping someone install a MegaSquirt.
S4 engine is a recent rebuild of unknown quality. As such, it's being sold at a core price, if I chose to buy it.
Ditto with above mentioned S5...
All three are long blocks with the exception of the S3 13B which is missing oil pan and front cover...
I also have my stock 12A that I have yet to pull.
So.. I have a HUGE pile of parts available, and I'm trying to build something.
My goals:
Street ported, possible forced induction at a later date.
EFI, MegaSquirt. Preferably 2 stage injection, FC primary, GSL-SE secondaries.
FC Ignition controled by MS (Trailing works now. )
I'm still trying to figure out which set of housings to use. The N/A diffusers will be removed.
S5's were similar to S4's except they have electric OMP (Which I do not like.) Lighter rotors/higher compression... What else?
S3 engine is free, High mileage core (Close to 200K, still running.). Inexchange for helping someone install a MegaSquirt.
S4 engine is a recent rebuild of unknown quality. As such, it's being sold at a core price, if I chose to buy it.
Ditto with above mentioned S5...
All three are long blocks with the exception of the S3 13B which is missing oil pan and front cover...
I also have my stock 12A that I have yet to pull.
So.. I have a HUGE pile of parts available, and I'm trying to build something.
My goals:
Street ported, possible forced induction at a later date.
EFI, MegaSquirt. Preferably 2 stage injection, FC primary, GSL-SE secondaries.
FC Ignition controled by MS (Trailing works now. )
I'm still trying to figure out which set of housings to use. The N/A diffusers will be removed.
#6
Zoom Zoom Boom!
Join Date: Mar 2003
Location: San Francisco, CA
Posts: 2,312
Likes: 0
Received 0 Likes
on
0 Posts
I think it was mentioned that the S4 engines have less chrome flaking than S3 rotor housings.
Also, having opened up an S3 engine and a bunch of S4's, the exhaust ports on the S3 13B's are much smaller.
Also, having opened up an S3 engine and a bunch of S4's, the exhaust ports on the S3 13B's are much smaller.
#7
Rotary Enthusiast
Join Date: Dec 2001
Location: not in winterpeg anymore
Posts: 1,350
Likes: 0
Received 0 Likes
on
0 Posts
the primary runners are smaller on the se 13b's. IMO the se block is better just for the fact it has the grooves on the housings. Why, because that way you can lap the plates without sacrificing groove space, also stronger for boost. Just port the **** outta the se block. If you are really worried about chrome flaking get them cermet coated
JHBperformance.com does the cermet
JHBperformance.com does the cermet
Trending Topics
#9
wtf's a piston
Join Date: Mar 2004
Location: Englewood, FL
Posts: 1,717
Likes: 0
Received 0 Likes
on
0 Posts
If you are going to streetport and all that stuff do the s5, high compression is better in all applications. If you thought about going forced induction it would also be better, spool quicker, more horsepower with lower boost. You would just have to step up the intake cooling a little bit (as I'm sure you know), maybe throw a singlestage water/alcohol injection piece of mind.
#12
Moderator
iTrader: (3)
it all comes down to different schools of thought. you'll hear some say it's for a larger error margin and you'll hear some say that it's required for big power.
i'm of the opinion that you'll make the same power, just as reliably as you've tuned the thing, on either apex seal. i, personally, like the newer 2 mm seals - though i have nothing against the older 3 mm ones.
i'm of the opinion that you'll make the same power, just as reliably as you've tuned the thing, on either apex seal. i, personally, like the newer 2 mm seals - though i have nothing against the older 3 mm ones.
#13
Right near Malloy
Thread Starter
iTrader: (28)
Join Date: Dec 1999
Location: Behind a workbench, repairing FC Electronics.
Posts: 7,840
Received 509 Likes
on
345 Posts
Well, I tend to look at things from a Pro and Con standpoint...
Logic would dictate that given the same material, the 3mm would be stronger, but would cause more housing wear...
But there's probably more to it than that, as I don't know if it is the same material and such.
Logic would dictate that given the same material, the 3mm would be stronger, but would cause more housing wear...
But there's probably more to it than that, as I don't know if it is the same material and such.
#17
FD > FB > FC
The main problem with haveing that water seal grove on the cast iron pieces is the grooves themselves become prone to cracking.
Ive never seen the grooves on a rotor housing crack
Ive never seen the grooves on a rotor housing crack
#18
Right near Malloy
Thread Starter
iTrader: (28)
Join Date: Dec 1999
Location: Behind a workbench, repairing FC Electronics.
Posts: 7,840
Received 509 Likes
on
345 Posts
So here's what I'm thinking:
Rotor housings, Irons, and E-Shaft: S3
Rotors, If I can find some good ones: S5 N/A (After prying off the hood, I found out the N/A Engine that was swapped into the wrecked TII is an S4. Drivetrain is still TII though )
Oil pump, OMP: S4
Water pump and housing: S4
Manifolds: S5
Keep the 2mm Apex seals. Street ported. Remove exhaust sleeves in rotor housings. FD Corner seal springs, and if I can find R5 cast iron housings, use em.
Frankenstein engine. The best parts I can find offa anything else.
I might go Forced induction later on, low boost.
I remember there was a chart of Years, rotor weights, and compression ratios. I thought it was at Mazdatrix's site, but I can't find it. Anyone know about it?
Rotor housings, Irons, and E-Shaft: S3
Rotors, If I can find some good ones: S5 N/A (After prying off the hood, I found out the N/A Engine that was swapped into the wrecked TII is an S4. Drivetrain is still TII though )
Oil pump, OMP: S4
Water pump and housing: S4
Manifolds: S5
Keep the 2mm Apex seals. Street ported. Remove exhaust sleeves in rotor housings. FD Corner seal springs, and if I can find R5 cast iron housings, use em.
Frankenstein engine. The best parts I can find offa anything else.
I might go Forced induction later on, low boost.
I remember there was a chart of Years, rotor weights, and compression ratios. I thought it was at Mazdatrix's site, but I can't find it. Anyone know about it?
#19
Senior Member
Join Date: Jul 2003
Location: North Texas
Posts: 648
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Pele
I might go Forced induction later on, low boost.
#20
the s3 rotor housings have different spark plug location vs. the s4 rotor housings. Make sure you match the ignition system to the rotor housings. The s4's were the only odd *****, s3 and earlier along with the s5 and s6 all have the same spark plug locations.
#21
Right near Malloy
Thread Starter
iTrader: (28)
Join Date: Dec 1999
Location: Behind a workbench, repairing FC Electronics.
Posts: 7,840
Received 509 Likes
on
345 Posts
Originally Posted by couturemarc
the s3 rotor housings have different spark plug location vs. the s4 rotor housings. Make sure you match the ignition system to the rotor housings. The s4's were the only odd *****, s3 and earlier along with the s5 and s6 all have the same spark plug locations.
I was planning on using whatever the platinum plug is for the FC. My standalone controls ignition, leading and trailing based off the FC CAS.
#23
Thread
Thread Starter
Forum
Replies
Last Post
LongDuck
1st Generation Specific (1979-1985)
12
10-07-15 08:12 PM