top end numbers for V 8 sho

[KILLA]

My Speedometer Cant Read Any Speed Past 115, It Just Drops All The Way Back To Zero Or Jumps Around Between 20 And 50. Im Guessing The Only Way To Fix It Is To Buy A New Sensor...
Thoughts Anyone.

 

[JSIL1]

I used to hit 137 fairly easily when I first got the car, now I am lucky to get past 115. I kinda wonder if it aint the tranny. I remember reading that someone dynoed higher after they got a tranny rebuild.

 

[1stSHO]

When i added my APC stickers, mine hit 155MPH!!!

Add sticker and you will go faster!!

 

[hoboprodigy-]

my BOEING sticker added 30000hp

 

[venom]

My Speedometer Cant Read Any Speed Past 115, It Just Drops All The Way Back To Zero Or Jumps Around Between 20 And 50. Im Guessing The Only Way To Fix It Is To Buy A New Sensor...
Thoughts Anyone.

Only proven way to fix that is to buy a Gen 3 that is not a 98. That top end speedo problem only affects the 98's. The actual source of the problem has never been pinpointed AFAIK. 98 and 99 use the same ABS module (per Ford P/N), the ABS module reports wheel speed to the PCM. The PCM displays speed on the speedo. So it is in either of three places. ABS, PCM, or speedo itself (or possibly a combination of any of them). I believe the speedo alone has been proven to not be the case as I think Paul Nimz has a 98 speedo in his 96.

 

[KILLA]

That sucks... i can still go faster than that though right? i meen who needs a speedo anyways?

 

[venom]

That sucks... i can still go faster than that though right? i meen who needs a speedo anyways?

Yes the car shoud continue to accelerate until it hits the top computer limited speed of about 140 unless something else is going on.

 

[KILLA]

governer stops me at 4 grand. or about 115mph.

 

[stangeater]

I still don't see a vic pulling on a sho past 100.........that's when the sho shines. Also, you said that a 4.6 mustang had a hard time pulling on you past 100?? My brother has a 97 4.6 and I walk away from him in my 92 sho "like a freight train" anything after 3rd gear. The vic runs low 15's........most sho's in stock condition can do this easily, and with a few "light" mods they'll be well into the 14's. I'm not trying to hammer on you or anything, I've just never had that experience.

 

[sho_sc]

Take it from someone that has done more top end runs than anyone here. You can't depend on the speedometer, tach, rev limiter, or what someone else says about top speed mph. Most speedometers are so far off at high speeds they are laughable. Even speedometers that are "calibrated" don't give accurate top speed results. With the most accurate speedo or tach or rev limiter, once you are above 100 mph or so, minute variances in tire size/expansion make huge differences in speeds. At 150 mph, tire temperature alone can make a difference of 6-8 mph. The only way that an accurate mph can be obtained is by means of external stationary radar/laser, or GPS (+/- 2 mph).

 

[stephen newberg]

governer stops me at 4 grand. or about 115mph.

The Gen III should not have that happen. Sure you are not having a problem with your IRMC?

pax, smn

 

[SHOoff_NYC]

I did 125mph on the highway while racing a Lexus SC400. I think I coulda taken him but he was scared to pull any faster.

 

[venom]

I did 125mph on the highway while racing a Lexus SC400. I think I coulda taken him but he was scared to pull any faster.

You realize that makes you extra k3wl right? :corn:

 

[SHOZ123]

I did 125mph on the highway while racing a Lexus SC400. I think I coulda taken him but he was scared to pull any faster.

So you never left third gear eh?

 

[SHOoff_NYC]

You realize that makes you extra k3wl right? :corn:

a tid bit.

 

[KILLA]

The Gen III should not have that happen. Sure you are not having a problem with your IRMC?

pax, smn

Whats a IRMC? I know a fair amount about cars, but im still not familiar with alot of the abreviations you use. all i know is that something is stopping me from maxing out in my final gear.

I have taller tires on the rear, by accident, but is there a sensor in the back that is telling my computer that i am going alot faster than i am?

 

[Mr. SHO]

IMRC = Intake Manifold Runner Control. It moves the assembly of secondary butterflies to the open position at ~3350 rpms.

Factoids:
1. IMRC failures are very common if you don't tear the intake apart and clean the butterflies every 50K or less. The butterflies get gunked up and then the IMRC cable and/or wheel mechanism breaks under the strain. Replacing or repairing the cable and/or wheel is only a very temporary fix if you don't eliminate the binding of the butterflies.

2. The car performs just as well if you remove the IMRC and mechanically wire the butterflies so that they are always open. There is no tradeoff in performance or fuel economy. The only negative side effect is that on very cold mornings, you MAY get a rough idle and stumble for the first 30 seconds or so. After thoroughly cleaning the intake tract, I have eliminated this behavior. It's possible that the adaptive programming of the stock PCM has also helped mitigate the rough idle and stumbling.

3. The reason for #2 is that the V8 motor does not have true secondary runners like the V6 SHO. The V8 secondary butterflies merely allow the air to flow through the secondary intake valve on each cylinder.

4. 4th gear is useless for top-speed runs. Keep it in 3rd (O/D off) if you want to reach 144mph in any reasonable amount of time.

 

[ArkanSHO]

Yeah, I know, stupid thing to do in an enclosed space while on a Dyno but the owner said he had a Z-06 pull 175 and wondered if I could match it. I almost did but the noise was incredible and I chickened out even though I had another 2,000 RPM left. By the way, the speed limiter was eliminated by Doug Lewis on the X-Cal.
Speed Dyno run

 

[smokin joe]

my cousins 1993 ATX we had crusing at 140 with 5 people in it!

 

[smokin joe]

We had my cousins 1993 ATX pined at 140 with 5 people in it!