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Max speed for IVA form quick question?
AdrianH - 27/8/09 at 07:20 AM

When calculating the max speed for the IVA form do you use the Max steady rpm figure of the engine or use the rpm at max bhp. Just wonder what others have used successfully.

I guess it is to calculate the safe tyre speed.

1.8 CVH Type 8 box and 3.92:1 diff gives me approx 112 at Max BHP and 124 at Max steady rpm.

Which do I use, 124 mph?

Adrian


Flamez - 27/8/09 at 07:29 AM

make sure you have tyres rated to your top speed.


adithorp - 27/8/09 at 07:32 AM

It's only used to check the tyres are rated high enough. 124 sounds OK for that setup. H rated tyres are good upto 130mph.

However if you put something silly like 70 they'll think your taking the piss.

adrian


nstrug - 27/8/09 at 09:11 AM

Use Max RPM.

Nick


Bluemoon - 27/8/09 at 09:42 AM

I put 118mph, tire as my tires where rated at about 120mph (can't remember exactly of the top of my head).. Same engine ect as you (and dooner wheels to get ratios/speedo correct as using serria clocks).

Originally the 1.8CVH serria max speed was 110mph..

Worked for my SVA... I did wonder if he would accept 118mph as this was only 2mph under the tire ratings. Some have had to put 130mph or so to keep SVA man happy (and tires to suite).

I set it at this as I have a new set of wheels and tires but they where in storage and I didn't want to shell out for yet more tires!

Dan

[Edited on 27/8/09 by Bluemoon]


AdrianH - 27/8/09 at 04:33 PM

Thanks for the replies chaps have gone for the 124 mph.

If the car ever gets to that speed is another matter.

Cheers

Adrian


Ninehigh - 28/8/09 at 03:49 AM

What's this all about? How are you supposed to know how fast a car goes that technically hasn't been driven yet?

Iirc my tintop tyres are rated for 150mph, but it doesn't touch that...


Bluemoon - 28/8/09 at 04:35 PM

^^^^

Just a number for SVA/IVA to ensure you have the correct tire ratings... That's it.. Nothing to do with actual speed obtainable, same for normal tin tops..

But inspector will want to tires suitable for vehicles, as you don't know it......... So you could use the gearing plus max RPM to give absolute worst case, then get tires to suite.

Dan


Ninehigh - 28/8/09 at 06:10 PM

Ah ok, so I could just say 130mph, and have tyres rated to more than that. I guess it doesn't even matter if it can go that fast then...