[kevnsue]

I have a 1991 mustang LX 5.0 and I can not get it to rev past 5500 RPM.
I have changed the computer and that did not help. Right now I have full aftermarket exhaust with 3:73 65mm edelbrock throttle body. Cold air intake, and underdrive pullies. The car acts like it is hitting a rev limiter or maybe floating the valves. The car does have 158000 miles and is an ex California police car. I have had alot of these cars and I have always been able to pull to 5800 with no problem. I put a shift light in it to make sure the factory tach was not off and it was actually hitting 5800 but that was not the case. It flat is not pulling to 5800, HELP!!!!!

[DanTheMan]

why would you want to rev a car with 158k miles past 5500 in the first place?

[kevnsue]

Becouse it is a mustang and I know it should rev that high.

[DanTheMan]

it could be the fact that it was a police car and they might have a custom rev limit...

[1BADSTANG]

valve springs, replace them.

[1slo5.0]

Originally Posted by kevnsue I have a 1991 mustang LX 5.0 and I can not get it to rev past 5500 RPM. I have changed the computer and that did not help. Right now I have full aftermarket exhaust with 3:73 65mm edelbrock throttle body. Cold air intake, and underdrive pullies. The car acts like it is hitting a rev limiter or maybe floating the valves. The car does have 158000 miles and is an ex California police car. I have had alot of these cars and I have always been able to pull to 5800 with no problem. I put a shift light in it to make sure the factory tach was not off and it was actually hitting 5800 but that was not the case. It flat is not pulling to 5800, HELP!!!!!

For one thing it is not making any power at 5800 rpm. That engine is done at 4500 rpm without a head and/or cam change. Shifting at 5800 is making you slower. Secondly at 158,000 miles your valve springs are probably pretty worn out. Replacing them will probably allow the engine to rev to 5800 again but as I previously mentioned, reving a stock 5 liter that high is only going to slow you down.

[flattusmaximus78]

Prob is the rev limiter... but like darrel said your not making any power their with the stock end, so stop trying cause your just slowing it down the longer you hold that gear off.

[1slo5.0]

Originally Posted by flattusmaximus78 Prob is the rev limiter... but like darrel said your not making any power their with the stock end, so stop trying cause your just slowing it down the longer you hold that gear off.

The rev limiter cuts fuel off at 6250.

[trueblue01]

At 158,000 and 5500 - 5800 rpm I'd probably have myself a back-up ready on an engine stand. Not a question of if, just when.

[kevnsue]

You guy's must have miss read my thread! I said I have a 5.0 mustang not a 5.9 cummins in it! I wish I lived around where you guy's live becouse I would sure win alot of biscuts and gravy from ya!! I will be taking this thing back to the track and I will do a 4500 shift in each gear and a 5000 and a 5500 and we will see which one runs faster. I say the 5500 will take the win light. I would bet you biscut's and gravy but I am sure you all must live in the midwest some where.

[HMUSN]

I'm willing to bet most of there guys know how to drive.
trueblue01
1989 Mustang LX
10.98@126.7 NA

darrell
1990 Mustang LX
9.36@143 mph

[trueblue01]

I happen to like biscuts and gravy, my grannie's from Charleston. I launch at 5000 and shift at 7000 but my engine doesn't have 158,000 mi. We have a stock short block that we run to 6500 in the traps but we keep it "fresh". Our small block Fords embarrass the bow tie crowd regularly and they all have us by at least 75ci. No doubt these 5.0s will live to 200,000 but they get a little sloppy and to think one will live for long at over 5000 is a little optimistic is all. We go by "S&M Motorsports" and our motto is "beat on it 'till it breaks!"

[1slo5.0]

Originally Posted by kevnsue You guy's must have miss read my thread! I said I have a 5.0 mustang not a 5.9 cummins in it! I wish I lived around where you guy's live becouse I would sure win alot of biscuts and gravy from ya!! I will be taking this thing back to the track and I will do a 4500 shift in each gear and a 5000 and a 5500 and we will see which one runs faster. I say the 5500 will take the win light. I would bet you biscut's and gravy but I am sure you all must live in the midwest some where.

I didn't miss anything. Obviously you did. Why don't you tell me where your engine makes peak horsepower.


I sure do live in the midwest. Why don't you drive that turd up here and try to take my biscuits and gravy. I'll race you with my Lincoln LS. Everyone knows how slow they are, especially one that belongs to me. I know it will beat a stock Mustang that Johnny Racecardriver over revs.

[kevnsue]

Well this is what I am trying to do. I bought this car from a food donation program where people donate all sorts of things and then the food center sale's the donation and feeds hungry people with the money. Well some guy donated this car it is a 1993 LX Notch back that was in service as a highway patrol car. The car is in great shape except it does have 158000 miles, and being an old cop car I am sure they are not easy miles either. I put some bolton parts headers,H-pipe,mac mufflers, underdrive pullies,65mm throttle body, BBK cold air intake, 373 with auburn possi. I lowered it and put SN95 spindles, with after market five lug axles, and silver bullets on it all the way around on her. I took it to the track and every pass was in the 14.20 to 14.10
Problem is I lost the clutch. So I brought it home and put a Centerforce clutch set up in it. Now I want to take it back and see what improvements that made. I also put on a set of MT ET Streets for this round of passe's. I think the car should run mid to low 13.00 on this set up. My sixty foots were all in the 2.2 range and we know that 1=3 at the top end. That is what I am doing. I have a brand new D&D 347 that is going in this car but I just wanted to play for a while with this set up.

[kevnsue]

WOW Darell you need a chill pill buddy. I never said I would race you and win biscuts and gravy. I said I would bet you biscuts and gravy that this car will run faster shifting at 5500 then at 4500! And that bet still goes and I am going to prove it. Like I said I will run this car at 4500,5000,and 5500 and see which pass makes the better time. So chill my brother and turn down the stestosterone level's a bit.

[1slo5.0]

Originally Posted by kevnsue Well this is what I am trying to do. I bought this car from a food donation program where people donate all sorts of things and then the food center sale's the donation and feeds hungry people with the money. Well some guy donated this car it is a 1993 LX Notch back that was in service as a highway patrol car. The car is in great shape except it does have 158000 miles, and being an old cop car I am sure they are not easy miles either. I put some bolton parts headers,H-pipe,mac mufflers, underdrive pullies,65mm throttle body, BBK cold air intake, 373 with auburn possi. I lowered it and put SN95 spindles, with after market five lug axles, and silver bullets on it all the way around on her. I took it to the track and every pass was in the 14.20 to 14.10 Problem is I lost the clutch. So I brought it home and put a Centerforce clutch set up in it. Now I want to take it back and see what improvements that made. I also put on a set of MT ET Streets for this round of passe's. I think the car should run mid to low 13.00 on this set up. My sixty foots were all in the 2.2 range and we know that 1=3 at the top end. That is what I am doing. I have a brand new D&D 347 that is going in this car but I just wanted to play for a while with this set up.

With ET Streets and the minor bolt ons that are done to the car will run low 13s with a 60 foot in the 1.7 area. Either way I'll still race you with my LS. Just let me know when you want to take my "biscuits and gravy" or at least make an attempt at it....

[superman5.0]

Originally Posted by kevnsue WOW Darell you need a chill pill buddy. I never said I would race you and win biscuts and gravy. I said I would bet you biscuts and gravy that this car will run faster shifting at 5500 then at 4500! And that bet still goes and I am going to prove it. Like I said I will run this car at 4500,5000,and 5500 and see which pass makes the better time. So chill my brother and turn down the stestosterone level's a bit.

i bet you wont, with just bolt on power you are shifting too far out of the powerband, thus slowing down as you drive down the track, making for a slower ET. your car only makes power from certain rpms and you obviously do not know your powerband.

[1slo5.0]

Originally Posted by kevnsue WOW Darell you need a chill pill buddy. I never said I would race you and win biscuts and gravy. I said I would bet you biscuts and gravy that this car will run faster shifting at 5500 then at 4500! And that bet still goes and I am going to prove it. Like I said I will run this car at 4500,5000,and 5500 and see which pass makes the better time. So chill my brother and turn down the stestosterone level's a bit.

I am perfectly chilled. So where does your engine make peak horsepower anyway?

I've been racing Mustangs for the last 15+ years. 4800-5000 rpm has consistently proven to be the best shift point for every stock Mustang I've raced. The engine peaks at 4500. The heads and cam don't support much rpm after that.

[1slo5.0]

Originally Posted by superman5.0 i bet you wont, with just bolt on power you are shifting too far out of the powerband, thus slowing down as you drive down the track, making for a slower ET. your car only makes power from certain rpms and you obviously do not know your powerband.

Exactly which is why he is only running 14.2 with it now. That car should be easily running 13.70s-13.80s. Even my stock clunker 88 GT ran 13.90s with a shifter, K&N, a Dynomax catback and stock gearing and stock tires. But I didn't shift it at 5500 or 5800 or whatever.

[superman5.0]

i have an auto with hci and i only have my shifts set at 5500 which i still think is a bit high but my dad said otherwise