i KNEW that they ran on LOWER octane than normal. so this is how to get it. maybe this will help my S4, stock port NA run 14s easy.

Rob said that these were PP cars, so im not sure if it would work all that well on stock port NA's.

but, i AM running premix in addition to the stock OMP, so maybe im on my way to making my own "RACE GAS"

chris

 

no S4 N/A can run 14s w/o engine porting. Even with my S5 and mods (which include intake mani. porting), I can only hit low 15s....

 

I SOOOO beg to differ!

I guarantee that my car, without the street port, and minus the A/C, P/S, and stereo.. (so, well over 100lbs weight reduction) would easily be still running 14's....(high though)
I doubt my steet port is good for a over a full second in the 1/4...who knows...

Oops.. I just saw the "S4" condition... well, it still can be done.

Good engine with excellent compression
Intake ported, with a K/N, and TB mod.
6 port sleeves smoothed, cut 1/2, and locked into place.
No emmisions of any kind of course.
Header, full free flowing exhaust (dual or single).
Lightweight flywheel, and some 225's in back...
No PS, AC, maybe strip the sound deadening.
Definately an S-AFC, and bump timing up a few degrees.

For an S4, That should do 14's with pretty full interior.. if not- gut it, and it will.

The thing is, most s4's have a lot lower compression than when new.... all the ones I've driven have, and damn they're slow...

And oh... the whole octane thing is correct... however, it won't make your engine LOOSE power running at higher octane, EXCEPT at VERY high RPM's, where the combustion time is so small, that the slower combustion of the higher octane gas doesn't allow for full combustion!
At lower rpm's (probably under 8000) the higher octane has the same power potential, since it combusts to the same gas (air gas) volume.... pushing the rotor.. .it just takes longer to reach it's expansion maximum....

People that run 94 octane all the time in their FC's (NA, or TII under 15 psi) are nuts, and wasting money though... sometimes the higher octane stuff does contain a higher concentration of cleaners though, but it all depends....

 

By Rob, you mean Rob Golden, at Pineapple Racing. CJ

 

i think thats what i said when i said this:

guys, i had my car weighed, and its 2720 lb WITH the driver (about 200 lb driver) so put that in your pipe and smoke it. thats WITH a full 2+2 interior. if i had a better launch with NO wheel spin, i dont see why i cant run a 15 flat, if not a 14.9.

pile on top of a good launch, good shifting, good compression; Pineapple sleeves and a mazdatrix header, and possibly match ported Upper and lower intake. you dont think i can break 14s w/ that set up?!

i think i should do it, just to prove you nay-sayers wrong. if someone doesnt buy my car first.

chris

 

You can do anything with any kind of engine with minor mods you can get a good 40 hp out of an n/a with good exhaust! cold air intake no a/c better spark plugs and higher performance feul pump and better injectors and changing your pulleys to low weight pulley's and an electric fan! i am sure with those mods you could easily run high to mid 14's without porting!

 

Better spark plugs? What could be better than the recommended NGK's that were made for that engine. Every other plug I've ever tried lasted about 1/2 the milage if not less that the proper NGK's and there was no performance gain.

By better injectors do you mean larger? If so that combined with a "high performance fuel pump" will almost guarantee your car to run worse. Making your car run rich is a great way to get worse gas milage as well as worse performance.

40HP gain while retaining the factory AFM? Good luck. I'd like to see it.

 

Dude why don't you watch some racing. The richer you run the more hp you get. At least thats what the indy guys say. I will believe them before I believe someone on a forum. Thats why they run lean, To get better gas mileage and the last lap run full rich. It makes more hp for higher speeds. Just what they tell me anyways.
Charles

 

as long as you do not droun your engine with the gas.

 

so for stock, what octane do you use?

 

Hey peacekeeper you got it wrong man, an engine will always have more power if you run it lean, although you have a greater chance of blowing that way.

 

If running rich is the way to go then why do people get the S-AFC and lean there mixture out? To make more HP. What happens when someone installs larger TII injectors on their N/A? It runs worse because its running rich. What about a TII fuel pump on an N/A? Its a waste of time.

telus.net - Just run the 87 octane gas and you will be fine for an N/A engine.

 

Wow..lots of misconceptions on here..People like bambam and PPnos have dynoed thier car with S-AFC , timing exc...Thiers proof.

Lol...My car is juuuuust about a 14s car already with minor mods...89GXL 180 lbs weight reduction and bunch of cheap little stuff.

I beat this 3000GTSL with intake exaust running 15.3 Its a 94 224 stock hp. I beat him by 3 cars on his bad launch and 1.5 cars on his good launch. That night I new I ran a 14.9 or 15.1 at least. Engine stock rebuild 20,000 miles ago with perfect compression and some top end mods.

 

cheap gas ansd N/As DO mix well... ; )

now if we could only find some of that olde' leaded gas ... yummmm

 

Leaded gas is the equivalent of really high octane gas. Thats how the old musclecars got away with running 12.5:1 compression.

 

To clog your cat or protect your soft valve seats?

 

no for my lawn mower .. ; P

i didn't mean that as a technical comment, it was merely a reference to the era of nasty leaded / low octane gases of the 70s and early 80s before all this fancy clean high octane stuff was avalble....

sheesh..

 

Well guys it may cause the rotary to run bad but the crew cheif I talked to for this indy racer said the more lean they run the better gas mileage but lower hp, and the richer they ran the morehp and shity gas mileage. He said going from way lean most of the race to ful rich adds like 50-60mph for the last and fastest lap. If they aren't on a caution the last lap. Thats how the guy at the indy 500 won this year. he went ful lean and dumped as much fuel as he could into the engine with out flooding it. then the caution came out on a back turn and he coasted in for the win on .04 gallons on gas. He didn't make it to the winners circle thing. the car died on the victory lap. Thats what I was told.
Charles

 

I think he was pulling your leg.

 

richer does not mean faster. it means slower.

see, you run FASTER when you lean it out. when you lean it out, the flame gets hotter, and since its hotter, it expands more, pushing more against the piston. the problem is that when you lean it out too much, it gets too hot.

you can enrichen things to get rid of knock and cool your EGT's down.

for instance, when tuning a DSM, say, your EGT's are 900*c at the top of 3rd gear and you have a knock count of 40. you need more fuel.

add more fuel via AFC, your egts will go down 50-100*C, your knock will go down to 20, maybe lower. you have more fuel.

the way this makes you faster, is that you can run more advance, since the knock is subdued due to the lower cylinder temperatures, so you dont have hotspots which will auto-ignite the mixture in remote places in the cylinder.

adding fuel to an unchanged set up makes you slower, it slows the burn cuz there is more fuel to burn. if it doesnt all get burned, then you have black exhaust. more soot in the tail pipe.

but the problem w/ Rotaries is that you can really have any benefit from advancing timing. especially since that these engines should be tuned for zero knock anyhow. the instant you have knock or detonation, is the instant you need a rebuild. so you cant really have any gains from tuning out knock.

and FYI, the lead in gas, isnt really a dissolved pipe...its called Tetra-ethyl lead TEL.

but seriously tho, if dumping extra gas into your rotary was so great, then how come we dont ALLLL run 550 injectors on our NA's as Basic performance upgrades???

chris

 

sorry about that...i need to read a little close at times.

 

wooohooo flybyux2.... thank you for straightening people out.. (good s#it, man )

 

Interesting statement there "bambam7", what was it, "The thing is, most s4's have a lot lower compression than when new.... all the ones I've driven have, and damn they're slow... "? Well only thing I can figure is that you have driven the worst s4's on the planet OR those million dollars worth of mods on you rex have jaded you! I say this because the s5 are basically the same as the s4's, with age brings lower compression. And "damn there slow.."? That sounds like something I you would hear from the owners of the FD's when they talk about the s4 OR the s5! I have a 88 TII w/ 95K on it and the owner of that last Mustang I took out a few weeks back would certainly disagree with you here!

 

I am almost 100% sure that he was talking anout NA's.

 

<-- S4 N/A... 14.601 ET stock ports.. slow?... not for an N/A