I think my engine is beginning to drink coolant, so I'm trying to plan ahead. I'd like to do a new engine. Here is the breakdown:

I prefer n/a
I'd like to make around 200whp
I'd like to run an IDA style carb, to keep costs down. This isn't a daily driver anymore, so I don't need the drivability of EFI.
I don't want to have to spin more than 9,000rpm
I'd like to keep the budget around $1500-2k, if possible

Some questions. I've seen some people get as much as 230whp out of streetport engines, but I see this as unrealistic without a huge amount of time on the dyno for experimentation. Is 200rwhp achievable out of a moderate budget, n/a streetport 13b?

I obviously have the stock 6 port now, but it seems like the 4 port engines respond better to porting. So this points me in the direction of a Tii or REW long block. Opinions on these?

I can't recall at the moment if my 6 port header will fit a 4 port block, I'm inclined to say no. My header is also probably not ideal (racing beat collected) for peak power either, so I was thinking one of the more exotic headers (like defined autoworks or something) would go a long way towards power.

For 200whp, would that be more appropriate for a weber 48 or 51 IDA? I like the weber over the holley setups primarily because of quicker throttle response. And they look damn cool. Will my stock fuel pump be too powerful for a carb? I know the IDA configuration is more towards high-end power, but this I don't mind. This is to be a car for backroad-blasts and maybe even a bit of late night freeway fun.

If I do go with a turbo motor (either t2 or rew) will the rotating assembly be too low compression? Would it make more sense to do an S5 engine with T2 or REW irons?

At this point I'm not sure whether I want to actually build the engine myself or not. Leaning towards yes. I know I don't want to port it myself...that is an art form I haven't the years to learn.

To summarize.

200whp, N/A 13b: What block? What rotating assembly? What port? What fuel delivery? What intake? What exhaust? How much money?

If this post isn't convoluted enough, the final plan is to build this engine, temporarily, for my S3 car, but install it in an S1 car later (when I have time, money, and space for a second RX7), then restore the S3 car back to as-new stock. The SE is mostly original I think it deserves to stay that way. My S1 car (when I get it) will be the stripped out barnstormer. And don't worry S1 lovers, I'm not going to do this to a pristine example. Probably something like an ex IT-7 car.

 

Hmm, or you could pour a bottle of Alumaseal into the radiator and worry about it a few years from now. 25,000 miles now and still going strong...




.

 

Haha. Well other than the fact I might have to, this is something I also want to do.

 

Ah, the old upgrade excuse. I completely understand...

 

Well there are some dynosheets on this page with 180rwhp out of a 13b streetport and a Weber IDA. The 230rwhp you speak of is full blown budget, lots of R&D on the dyno and no compromises. The S5 n/a 9.7 compression ratio rotors are the way to go, Rx-8 e-shaft cheap, light and with the tapers & teardrops built in courteosy of MAZDA. Pic of said parts below.

You'll make more HP from a 4 port motor than a 6 port. S6 block can take a lot of porting. It'll be easier to reach your goal with a BRIDGEPORT.

The 51 IDA will make some more peak HP but move the powerband up 1000rpms since the larger throat = less velocity. I think your goal is very ambitious considering most used motors are just plain worn out and you're talking used on that budget.

Good luck!
Brad

 

its all budget dependent...

the easy part is your RB header/exhaust will bolt onto any 13B, so you can at least start with that, and upgrade later.

the IDA works, but its not cheap! plan on $700-900. you need the carb+ jets+manifold+fuel pressure regulator. EFI isn't more....

you should be able to use the -SE fuel pump, or i've been told that, but haven't myself

for the engine, are you going to rebuild the stock engine or start with something fresh?

the low budget way would be to just buy 12A end irons and just use the rest of the -SE block.

basically all you NEED is a 4 port block, with a street port. the higher oil pressure is good, baffle plate is good. the 9.7 rotors are nice, the FD/Rx8 stat gears are nice.

 

EFI (the way I would want to do it) would require a set of ITB's (as much as the carb itself) PLUS injectors, intake manifold, larger fuel pump, AND engine management. EFI would be far more expensive (i'd say at least $1500) for a roughly equal setup.

Here is what I'm thinking:

S5 N/A longblock (all stock assembly to keep costs down) with ported S6 irons, 48 weber IDA, racing beat header. Would that combo push more than 180whp you guys think? The S6 irons would go right in with the S5 housings, right? Then I would just use my SE front cover to mount the engine, correct?

 

I'm building a 4 port 13b right now with new ported -se housing, -se rotating assembly with all new seals, ported re-nitrided 12a end irons and am still trying to find an old tall port center but am getting tired and will probably just use a 12a ported center.

Putting a 48 ida and racing beat exhaust. 180 whp should be easy, shooting for 200

Total spend was roughly $2500 which was mostly the new housings, porting, and all new seals. Had fuel and exhaust.

Long story short your budget is awfully low.

 

Well that's not the limit, it's just the goal. If I allow myself 3,000, I'll end up spending $5,000!! lol

 

yeah that would work. you should look at the cost difference to do an REW with 9.7's.

brad's right a bridgeport would make it easier to do 200+, doesn't have to be a huge bridge either.

or just quit F-ing around an go P port, the only penalty is noise...

 

I want to do a p-port eventually. But if I go PPort it's gonna be the best of the best components. And three rotors

 

UPDATE:

Well I investigated my coolant problem a bit more. It isn't burning it, it's seeping it from between the front cover and first iron. Why is this happening? I recently installed a new water pump and it has only been seeping it in the last few weeks.

 

leaking between the water pump housing and the front iron?

 

Water pump housing? I suppose that's what it is. It's coming from between the front iron and whatever the next 'plate' forward is. The one the water pump bolts to.

Edit: I see now. The water pump housing bolts to the front cover, and then the water pump bolts to the housing. Yes, it's leaking between the water pump housing and front cover. Why is this happening?

 

anyone?

 

apparently the gasket between the housing and the front iron has failed, either that or the two bolts that go through the pump and the housing at the opening between the housing and the front iron are not tight. Fairly easy to take apart and reseal. Much better than building an engine, Rejoice!!!!!!!

 

I bet it's the bolts. I'll re-tighten and see if that fixes it. If not, I'll replace the seal.

edit: I've been reading about waterpump shims and the problem/symptoms seem to be pretty much in line with the shims. However, I don't remember there being any shims when I took the old pump off, and I'm not really sure where they go or what they are there for. Anyone have any info?

 

Read a bit more. It appears the shims go in between the WP housing and the engine block. I didn't take the housing off, so they will still be there. Could this be as simple as not having the nuts tight enough?

 

maybe. its also possible that when you did the water pump, the gasket got disturbed, and isn't happy anymore.

 

I tightened them up and drove it around for a bit. Couldn't find any seepage. Hopefully it stays that way.