as the question in the subject matter states.

rack your rotary brains to produce a formula, prescription, list to get the result of 270hp out of an S5 n/a.

limits: no turbo, sc, or nos. nothing above streetporting

alright..................go.............

 

RWHP or FWHP? makes a big difference.


CJG

 

270 with only a street port and no form of forced induction? Hahahaha. Maybe you can get some 12:1 compression rotors and be very careful.

 

rotortuner- I thought it was a given, but the 270hp figure is to be considered as 270fwhp. Usually when car magazines are talking about hp and they put a figure, i.e. 270hp, they mean flywheel horsepower, unless specified otherwise.

c'mon yall, let's not all be ignorant (aka ignant). smile.

got the jokes haha. c'mon guys be a little more optimistic, and not even necessarily all the 270 fwhp, but just as close a formula you can put together to get there.

take this as a problemsolving challenge:

start with a 1990 n/a S5 = 160fwhp/ 140 tq.
add a little pineapple 6port sleeves,
w/ a smiggen of apex cone air filter,
a bored out throttle body,
extrude honed intake manifold,
streetported (portmatched to intake manifold) motor,
underdrive pullies,
electric fan,
header into 2 1/2" exhaust,
complete w/ your very own standalone computer (wolf).
(seriously) anything else to put in/ add to the mix to get to as close 270fwhp we can get????????
( yes, I do realize it's reaching and yes, it is an expensive setup, but help me out w/ the goal/project)

 

Your going to have to ditch the stock intake manifold and go with either a IDA or DOCE one with 50mm Throttles to get that kinda power, plus it will have to be a Bridge port, unless you get a HUGE street port.

 

https://www.rx7club.com/forum/showth...hreadid=211545

 

Either a very large, well done street port with custom intake manifold or a bridgeport.

 

I dont think its really possible. the 12a pp makes only about 10 hp more. I think you could mabe get in the 250 range with a IDA FI set up. The ports will have to be ground so far that you break into the water jacket and then even farther, then back fill the holes in with epoxy, while maintained just a """stock port""" location. The the exahaust port will have to be very large. Lightened/balenced rotors so you can get more rpm to make more hp. dry sump and electric water pump to take loads off the engine. Then go with the 3.1 lbs. AL quarter master flywheel and 5 inch borg & beck clutch. Guru racing 2 piece eccentric shaft with center bearing to really hold the RPM. Ceramic seals adda little too. under drive pulleys. This should get an engine to around 250 FWHP. What do you guys think? I am still kinda doubtful. ???

CJG

 

Huge port 13B w/ light rotors and well-tuned EFI and spin it up to about 11.5 on alcohol. Easy 270 to the wheels. Not gonna happen on a streetport, sorry.

Brandon
BR7 Racing

 

I think it's very possible...i used to have one of those engines and it kicked ***!!! I used to have a radical street port on it but now i find out some people also bridge them. With the street port i approximate i had around 240hp at the wheels at least. I'm actually thinking of getting that engine again. Just with the holley and good exhaust it can make close to 200 at the wheels.

 

Ddue, unless you have a dyno number, NOT G-tech, then I am going to say that your smoking crack. Unless it had a turbo or N20, or something of that nature.

 

Lets see no turbos, no nitrous, no supercharger, and nothing above a streetport. Hmmm. Well the logical thing to do if those are the limitations are to either add a couple more rotors or add a 2nd engine to the back of the car somewhere. You would think that if it was possible to accomplish what you ask then it would have taken less than 14 years since the S5 was intoduced for someone to do it. That haven't because it can't be done. Period. End of story. At least with currently available parts this is true. If you would like to custom fab up some 16:1 compression rotors, add a center bearing, balance and lighten up the entire rotating assembly by 50%+, run on nitromethane, rev the engine up to 14000 rpm, and custom fab up the absolute perfect intake and exhaust system to go with the crazy big "streetport" then you could probably hit it.

 

I got the numbers from assuming that stock it makes 160 rwhp, if it's 160 fwhp then my numbers could be off a little bit. But i'm sure whatever it is, after i had it ported and with a carb and exhaust and some other mods it was making over 200 at the wheels n/a.

Maybe i'm smoking crack but i believe this motor should be able to make maybe not 270 but somewhere around 250 fwhp. Dammit, don't destroy my hopes If i'm wrong feel free to correct me.

 

If your butt dyno is calibrated to think that a S5 N/A is 160 rear wheel horsepower, you have problems bud!

You would be HARD PRESSED to make 270 flywheel HP. You'd have to concentrate *everything* towards the upper RPM range. And then you'd still lose in acceleration to people who have more realistic engines setups because they have a useable powerband. (Not to mention that you will be rebuilding... frequently... because engine wear goes up exponentially with RPM)

Oh yeah, and your MPG will be pretty shitty too. WHy not just get a small peripheral port or a small bridge port and get a useable powerband?

 

12a big street port can be about 200 fwhp, so a 13b with higher compression rotors and a street port should be about 50 hp more. Plus balancing, light weight flywheel, msd boxes...etc..should bring it very close to 270 fwhp

All i know is if i had the same motor in my '84 as i used to have in my '91, i'd be hitting 13's all the time.

 

It only takes about 240hp to crack a 1st-gen into the 12's. Less if you have plenty traction (well under 2sec 60's)

 

240 hp is good for 13's MAYBE, not 12's. I dynoed 271 @ the wheels with my turbo 2 setup and ran 13.3@111mph with almost a 2.4 60 ft. I was spinning the tires until I hit 4th gear. Slicks would have got me deep into the 12's.

 

If you're hitting 111mph you should have been in the mid 12's.

271 wheel HP and 111mph in the quarter? Something doesn't add up, unless your car weighed around 3000lb with driver. Unless you were *really* spinning the tires (just sitting there) in which case you gotta learn to drive, man

 

No **** I should have been in the 12's. Didn't I say with a sticky tire (slicks) I would have been deep into the 12's? And thanks but I can drive I'd like to see you take 3 passes only and find the best technique with 205/50/15 street tires and 271@the wheels.

Have you ever driven a turbo 1st gen.

 

.. I've got a S5 NA , with the mazdatrix streetport port matched intakes and all the other little things that could possible help including a Super AFR.. if you COULD make 270 hp then i wouold say that you'd have ZERO TQ up till the 5500 range, becuse right now , the way mine sits.. off the line until it hits 2800 in fist gear it's slower then a chevette with 5 'all you can eat buffet' olympians in it. In fact on an uphill run I was killed by a new z24 cavi.!! as if!!

This car is getting a Votec centripital SC put on it very very soon.. i've had it with NEON's and Civic ricers having a go at this thing.

 

That's when mine used to kick in at around 5500k..really don't see how ricers could be giving you any trouble at all though, they never bothered me with that car.