Running a stang in mexico

[cucho]

Hi, Im from Mexico, i live nearly to the USA border aprox. 3 hrs. I have a 84 Mustang, I have a pure street car Ill drive the car all days to work, with the AC, power steearing, here is a hot place in sumer the normal temps are around 120 F, is hot , well this the thing my car runs 12.90 with a 1.68 60 ft. , we are on 700 ft. from sea level, i got a manual trany 5 speed, slicks on it an more stuff that im gone a mention to you guys, nobody here like the fords, all the people wants chevys im talking about a 98% like chevy. Well Ill be thinking and reading and cars with my same 60 ft. runs more i dont feel the car realy fast pasing the 200 meters, ill be thinking that i need other gears in the trany, cause i have a 4.10 on the rear end. what do you guys think. I really want some mustang friends. About my engine and my suspension im gone a talking, with you guys in the next time.Thanks for your attencion.
Sorry about my english.

[bigred90gt]

If you tell us what you have done to your stang, we could give you a better idea. What kind of mods do you have? What rpm are you shifting at?

[cucho]

Ok. Lets start with engine, 306ci, 9.6 compresion, Roush 180 cylinder heads with 1.94 and 1.60 ported(with the ported work this cylinder heads flow att 550 lift 265 cfm intake and 192 cfm exahust), hydraulic roller cam duration @50 224-232, 556-565 lift, 112 lobe center(competition cams), single plane intake manifold, 750 holley carb front jet 73 rear jet 77, MSD 6AL, MSD distribuitor,MSD launcher control, 1 5/8 Hooker headers, race cluth, T5 trany with a Hurst shifter, 8.8 rear end with posi unit and 4.10 gear ratio. M/T slicks 26*10, Lakewood lift bars, and I have a couple of Air bags the ones that you put into the springs. I shfit at 5600 rpms. and i croos the 400 meters at 5300in the four gear.

[LX5liter]

I think with that cam you should be shifting a little higher in the rpm range (6200 Approximately, if you have a decent bottom end). Also what kind of single plane intake do you have? Is it matched (powerband wise) to the cam? Does it feel like its losing power after half track? Or do you just think it should be quicker?

[cucho]

Ill already tried to sfhit at 6000 rpms, but if i do this i shift the fourt gear nearly the 400 meters. The single plane manifold its a holley and it have a match port, Ill be thinking to change but all the single plane manifolds are the same, i can use a victor jr. cause its to much for street, and the air gap well i lived the line at 5500 rpms the air gap would be great with a automatic trany, what do you think. It doesnt feel loosing power in the engine Ill think is someting with the trany or rear end. And i just felt that it most be quiker

[erl2589]

What is your trap speed at the end of the 1/4 mile. That can give you some idea of your engines power.

[cucho]

at the end the speed its around 96 milles

[LX5liter]

Wow. 12.90 @96 mph? If that It sounds like you're definitly losing power in the top end somewhere. I think you are either running out of air, fuel or spark. My guess would be fuel. What do the plugs look like after a blast? Do you hear any misfiring?. Your definitly making power by your 60ft's,but your losing power at the top end. What kind/size of air cleaner are you using?
I don't think the problem lies with the tranny or rear end. If it was an automatic then maybe, but not a standard. And with your 60ft times I think your clutch is holding just fine.

[cucho]

I dont think its fuel the plugs look great like little red and white, it most be air cause I have the normal hood, and when I race the car I take out the air filter, a cowl induction hood would help what you think, And also Ill be thinking in the flywheel myne its a 11 inches this one help at the start and maybe its not good at the end what you think, you guys use the 10.5 flywheel . Thanks .

[erl2589]

Hmm...

Your photo looks great, front wheels up, nice 60 ft time, not a bad 1/4 mile time either. But 96mph in the quarter is really slow, that's about what a stock 5.0 will run.

Did you run that time in the 120 degree heat? That may account for the low top speed. I've watched a lot of dyno pulls and with those heads you may not be putting out more than 265/285 hp at sea level in cool air.

Do you have access to a chasis dyno down there? That should give you a good idea how your engine is performing, then you'll know if you should be looking at clutch trans etc. or engine.

Also compare speeds going down the track to others running a little faster than you. Maybe you can pinpoint where where your speed is dropping off.

By the way, I've seen charts which use the engine displacement and the RPM to calculate the CFM required for the engine. I think 750 cfm is way to much for 5.0 at 5300 rpm

[Shaggy]

Is your Holley a mechanical or vacumn secondary? if it is a vacumn secondary then I suggest replacing the spring in the vacumn pot to about the third from lightest and shifting out of first around 62 to 65 and then 6000 for second and if you find yourself getting close to the 4th gear shift after the 300 meter mark then try holding it in 3rd as long as you are not going to carry it past about 6500 in 3rd. If the carb is mechanical make sure the linkage to the secondaries is working properly. To run high 12's with a trap speed under 160Km sounds like fuel or air as stated before. From what others have said and your responses my guess is you are running primarialy on 2 of the 4 barrels of the carb.

[cucho]

My holley is mechanical, and definetly its not running in two barbel, i guess is air what my car need. Ill tried to put a video in here just that you guys saw the car ok. Thnaks