GPX - Top Speed

[Hercules Q. Einstein]

I've got a standard '95 GPX, 60k miles, just derestricted and fully serviced (except for back 3 plugs).
The car can get up to 120MPH very quickly but after that not much happens.
I might get 125MPH out of it but my '99 406 HDi can do 130MPH for god's sake.
Is this all I can expect to get or is something wrong somewhere.
I'm gonna change the back 3 plugs to see what happens.
I also get a really rough vibration going through the car between 65MPH-75MPH and it's definitely not an issue with the wheels.

Any thoughts?

[DirtyLopez]

Your delimiter may not working properly if you can`t go more than 125MPH... My GR is not derestricted (yet) and can do the same (speedo needle about 10KPH over 180KPH)
According to my knowledge a derestricted GPX can do about 150-160MPH

[Muad_dib77]

Yeah doesn't sound like the derestrictor is doing it's thing..

[CJ]

Any thoughts?

You obviosuly have a private track at your disposal - as I'm sure you're aware, FTO-Ireland does not condone excessive speeding on a public road.

IIRC, lads have got 140mph out of GPXs. You will know very quickly if the limiter is working or not - once you hit 121mph, engine revs will drop and you'll be dragged right back to 112mph.

I wouldn't get hung up about top speed, at least you have the 406 to fall back on

CJ

[mcgon1979]

"I wouldn;t get hung up on top speed"

Exactly CJ. Sure how often do you get to the track to use it? Acceleration is better.

[Myfeckin FTO]

....I wouldn't get hung up about top speed.......
CJ

Its for this very reason I never derestricted my FTO - Performance is exactly the same up to 121MPH (as proved on a rolling road in my GPX) - why would you ever need to go quicker than that unless you're racing on a track (& it would need quite a long straight).

The usable performance i.e. 0-60 / 30-50 / 50-70 is far superior in the FTO than the vast majority of cars on the road. A top speed means little when it comes to a quick car - WRC rally cars frequently top out at 110mph due to gearing.

[Muad_dib77]

I amazed that you didn't derestrict your baby - seeing as you have a big long private track right out your door.

[Myfeckin FTO]

I amazed that you didn't derestrict your baby - seeing as you have a big long private track right out your door.

I'm not exactly the right person to preach road safety but you'd be nuts to do more than 120mph (in the context of the limiter - I'm not saying its safe to do 120mph) on a public or private road or race track without a safety roll cage and a helmet. Any mistake would mean certain death especially in an older design like an FTO - I wouldn't do it in the Zed either and it has 8 airbags and a much improved crash structure over the FTO.

Derestricting your FTO is a pointless exercise unless you're going to be spending time on track and also provided your FTO is properly prepared for these speeds - spend the money on better brakes or suspension and you'll have a faster and safer car.

[Muad_dib77]

MyFeckin' you're the safest driver I know - less time spent on the road = less likely hood of being rammed by some nutter..

Agreed 120mph is nuts without the proper precautions..

And of course we don't encourage speeding.. it's just not clever.

[Hercules Q. Einstein]

The derestricter works in the sense that you don't hit a certain speed and the revs bounce down like they used to.
Do you think it's possible that the derestricter is causing the car to display the wrong speed or could the delimiter actually be preventing the to speed being reached.
I'm testing on a private track and can get up tp 120MPH very fast,
after that I start running out of track but the acceleration after 120 does seem very slow.
Should it take a long time to get from 120MPH-140MPH?

Any suggestions why the great acceleration to 120 and then deadness?

[mcgon1979]

it does really sound likes its still restricted. should blast by 120mph no hassles.

[Hercules Q. Einstein]

No, before derestricting I'd hit a certain speed (112MPH) I think and all of a sudden the revs would temporarily and then pick up again.

This no longer happens since I derestricted but the very max that
I can now get is slightly over 130MPH.

I'm also still getting that rattle throughout the car between 65MPH - 75MPH.

[miss-enzo]

mine got to 120 on the rolling road......wouldnt dream of drivin that fast n the road...... but mine is still limited! ur man doin the car said if she wasnt there was still alot more in her!


ps why would u care what the top speed is u can only do 100km/h on the raods (unless a motorway obv!)


i dont see the whole "oh my car can do 150mph" sh*t who cares!! i mean are u proud of urself???? image what u would do to someone if u hit them at that speed!! *shudders*


enjoy being the big hero that u are drivin at stupid speeds!! try not to kill neone while ur doin it!

[mcgon1979]

mine got to 120 on the rolling road......wouldnt dream of drivin that fast n the road...... but mine is still limited! ur man doin the car said if she wasnt there was still alot more in her!


ps why would u care what the top speed is u can only do 100km/h on the raods (unless a motorway obv!)


i dont see the whole "oh my car can do 150mph" sh*t who cares!! i mean are u proud of urself???? image what u would do to someone if u hit them at that speed!! *shudders*


enjoy being the big hero that u are drivin at stupid speeds!! try not to kill neone while ur doin it!

I have to agree with this post. Fair play for posting it Miss Enzo. Unless your "private track" has a at least a 2 mile straight (which I seriously doubt it has to be honest) you shouldn't consider doing top speed runs. Doesn't prove much and the stopping distance and reaction times at this speed are beyond thinking. If you hit anything your car will fold up like an empty coke can. Whatever about discussin 0-60 times and drag racing etc, closed track high speed runs are a different ball game.

[Mustang]

i dont see the whole "oh my car can do 150mph" sh*t who cares!! i mean are u proud of urself???? image what u would do to someone if u hit them at that speed!! *shudders*


enjoy being the big hero that u are drivin at stupid speeds!! try not to kill neone while ur doin it!

He merely asked a simple question regarding top speed. Which should command a simple straight forward answer. I do not detect any hint of bragging or sense of pride. I've seen this bofore on motoring forums where somebody asks a question about top speed, which is then followed by a stampeed for the moral high ground. Let he who is without sin cast the first stone, people in glass houses, etc.
I am not saying I condone or defend travelling at such speeds, but the thread was started with what is essentially a technical question.

[Myfeckin FTO]

........ I've seen this bofore on motoring forums where somebody asks a question about top speed, which is then followed by a stampeed for the moral high ground...... .

Agreed - One of the reasons I dislike many of the mainstream forums.
FWIW - Its not speed that kills - Its stupidity that kills!

The guy has a problem with the top end of his car - whether this problem happened on a rolling road, a track or a straight empty stretch of motorway is none of my business.

[mcgon1979]

Well for what its worth guys, I thought I would just back up miss enzos comment. I know that anytime speeding is mentioned on here, CJ is quick to interject that its not condoned here, so I think miss enzos comment is 100% OK on this board. It's her opinion and I don't think she meant it to seem like she was attacking the guy. This is a thread about trying to top 120mph in a car, so lets not persecute anyone because of 'their own' personal viewpoint on it (whether they take the moral high ground, or the not). Forums are about viewpoints. Personally I find it hard to believe that anyone has a 2 mile straight private track which they are using as an FTO proving ground. Thats just me though. and yup Im not without sin

edited...
Just to add "Its not speed that kills - Its stupidity that kills!". I think we could debate that one. Many an excellent driver has been killed because speed robs you of reaction time. It takes away options. Your also more likely to suffer a mechanical failure at speed. It can be argued that stupidity kills, and speeding = stupidity because it adds so much extra risk.

I could also ask the original poster if he is wearing a 4 point harness, has a roll cage, and a helmet, and everything else neccessary for the high speed runs? etc etc. No point arguing guys. bottom line. speed increases eisk. no matter how good a pilot you are, or whether your on an a public road or a private track.

[Muad_dib77]

I've got a standard '95 GPX, 60k miles, just derestricted and fully serviced (except for back 3 plugs).
The car can get up to 120MPH very quickly but after that not much happens.
I might get 125MPH out of it but my '99 406 HDi can do 130MPH for god's sake.
Is this all I can expect to get or is something wrong somewhere.
I'm gonna change the back 3 plugs to see what happens.
I also get a really rough vibration going through the car between 65MPH-75MPH and it's definitely not an issue with the wheels.

Any thoughts?

All points taken - now lads & ladies.. any thoughts on this here technical problem?

[mcgon1979]

All points taken - now lads & ladies.. any thoughts on this here technical problem?

Could be a timing issue? Was the belt changed recently? The vibration at 65 - 75mph seems like it could be a factor here. You say its not an issue with the wheels? but it only occurs at 65-75mph not at a certain engine RPM. thats strange alright. It would be good if you could do a compression test and check timing.

[Hercules Q. Einstein]

Now we're getting somewhere.
I was thinking about the timing belt.
If I'm acccelerating between 65-75MPH and let my foot off the pedal,
i.e. just let the car cruise in gear at 65-75MPH then the vibrations stop.

God knows how long ago the belt was changed, it doesn't look too old though.

A bad compression reading would explain the power loss, might get that done.

How would I get the timing checked, this interests me more at this point.

I still haven't changed the back 3 plug, gonna do that before doing anything else.

-Thanks for you help...

[Muad_dib77]

If you haven't done a big service on the car since you took overship I'd strongly recommend doing so..

Fuel Filter
Plugs
Oil & Filter
All Belts
Airfilter

Basically anything cleanable needs cleaning and anything replaceable needs replacing..once it's done you know it's done and that those parts are all parts that will be less likely to cause trouble in the near future..

Once you're through those I'd recommend looking at bushes,brakes and any other wearables and moving parts that may or may not have been changed in the lifetime of the car.

[Hercules Q. Einstein]

OK...
I've just given her new
Oil Filter
Air Filter
Fuel Filter
6 plugs
4 front brake pads.

Now I can get 120MPH no problem in 3rd, when I bang it into 4th feck all happens, just a really slow climb to 130MPH.

Is it possible it's the gearbox?

The car drives perfect in 4th but a bang from 3rd to 4th at 120MPH feels as if you haven't changed gear at all.

....And I should add for legal reasons that I have a security guard friend that reluctantly lets me mess around on a private airfield after their employers have gone home and the place is shut down for the night...

[mcgon1979]

its a very strange one alright. Car should do 140mph+ easily....

[Hercules Q. Einstein]

Is there anyone else out there with a Tip GPX that can't really get over 130MPH?

Perhaps the delimiter chip isn't converting to MPH correctly.

I'll have a go with Sat-Nav tonight and see what speed that gives me.

[ftolam13]

0-60 in 6.8 0r 7.4 seconds (depends on which model and who you talk to or what you read !!) Theoretical top speed of around 155mph-160mph (De-restricted GPX MIVEC Manual - 113mph otherwise)