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garethbowers

Type 9 Top Speed?

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Are you sure the torque is ftlb and not Nm? I just did a quick search on the tinterweb and found

BMW 4.6L V8 400 BHP 370 ftlb

Mercedes-Benz unveils new four-cylinder diesel lineup, 204hp 370 ftlb

EVO 8 370 BHP, 330 ftlb

 

If you do have 370 ftlb you are definately going to need a stronger diff!

 

370Nm equates to 272.86 ftlbs

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Most manufacturer speedometers are deliberately set at around 10% over to avoid litigation from speeding tickets. Whereas a good sat nav providing you stick to a speed and cover more than a quarter of a mile are very accurate (stick 2 in the same car and they always read the same. I'm sad enough to have had 2 standalone and 2 phone sat navs in the car at the same time and they always read the same. Whereas as positional accuracy may only be around 10 to 15 metres. relative change of position compared with time (speed!) is very accurate.

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Thanks for the advice I'll try my sat nav. Yeah it's lb ft not nm. So you recon the box will die? Any other options? I'm looking to low blow my lump soon too?

 

Gareth

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I was a bit surprised at the readings too. I now have a heavily modded XE, but I ran a standard one for a while in similar spec to yours, polised & reconned head & twin 45s. It pulled 174bhp at the flywheel, 144 at the wheels, about 200 ft lbs torque.

It looks like your reading was taken in 3rd gear, based on speed & max power & the blurb at the bottom of the sheet.

All the RR readings Ive been involved with (lots) were done in 4th.

Using 3rd will slightly increase BHP but massively increase torque.

I would expect your engine spec to give about 180 bhp max at the flywheel with a good custom built exhaust. You will lose about 30bhp in transmission losses, so 150 at the wheels would be a very good figure, & account for the top speed you have seen.

Did the RR guy do a run in 4th?

Bob

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Hi bob I'm not sure what gear to be honest. I know nothing about tuning. He did say that he was very shorted with the figures and asks if it was just a standard lump. It goes nuts at 4k which made him think it may have a cam?

 

I'm hoping to get her out again the weekend. I've just bought a pulse converter so I can wore my digi dash up and calbrate it proper.

 

So my box should be fine then?

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The standard xe really comes on cam at 4k anyway.

the heavy duty box i got from BGH takes 220 bhp & 240 ft lbs...even that wont take 370 for long.

 

Take a look at your graph...at the bottom it looks like it says 3rd gear?

I run a 3.9 diff....my standard xe 144/174 bhpp pulled 6k in 5th (120 mph) it does 20 mph per 1000k in 5th, 16 mph in 4th.

Makesure your tacho is working & use a sat nav to calculate revs per mph.

Peak power will be around 6.5 k.

HTH Bob

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HI there. How much was your diff bob? Yeah i agree it does look like it says second gear. What are the figures likely to be in 4th then? Cant wait to get the speedo working now.

 

HOw do the different sie diffs make a difference? sorry to be ignorant but im really not up on the gearing side of things.

 

Gareth

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Ahhhh, the black art of the dyno :)

 

You power/torque crossing looks wrong, and according to my fag-packet calcs you've got a ~525BHP engine with those torque figures........................

 

It appears you've been lied to matey, I'd be asking questions of your Dyno operator...........

 

Of course they are all honest individuals, I'm sure something has been overlooked (quite possibly by me!) :p

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Hi Gareth,

a standard XE in reasonable nick, ie good compressions on all 4 pots, decent size carbs, ie min 36mm chokes, preferably 38 mm chokes, and standard exhaust should put out between 165 and 175 bhp at the flywheel. You will lose about 30 BHP through the transmission, so 135 - 145 at the wheels will be a good figure. That will feel REALLY quick, especially from 4k upwards. But it will be pushing a standard type 9 box. Using a 3.6 diff will allow you to use first gear, but it is still very low, but will not get the best from the high power band of an XE in 5th. A 3.9 will be far better in 5th, but useless in 1st.

My diff was a present from a fellow club member who was having a clear out. Check Ebay for a recent price, but make sure your half shafts are the right size & type there are 2 types LOBRO & push in, and two sizes, small & large (LOL) I dont have the measurements.

Your car should be able to pull 6 - 6.5 k in 4th using a 3.6 diff. Depending on wheels that should be around 110 & it should get there rapidly.

Who did the RR session? Is it a well known one? Has anyone from the club used them before?

HTH Bob

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Hi once again thanks for the info's.. I used a b garage in deeside. They are well known around our way. As said the car pulls great in all gears, just seemed to run out of gear in 5th my engine wanted to keep Goin lol.

 

Really worried about my box now as the previous owner has boxed it in and will be a knightnare to get at.

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