[race_prep] Guernsey Hillclimb 205 Build

[Cameron 16]

That's a load of crap, you can bend any pipe through any angle you like (up to around 210 degrees)!

 

Boom is just what you imagine it is, a deep droning boom at some engine speeds. It's caused by resonances in the pipes, which are a function of pipe length and other factors, but most importantly pipe length. I'm not saying it will, but it definitely increases the chances.

[wardy18 33 1 Cars]

Must of been their capability restrictions then, thanks for clearing it up!

 

Must say though I would much rather boom resonance than that horrible tinny raspy wasp noise that alot race cars end up with, hate it, a nice deep throaty sound is what I want!

 

What causes raspy exhaust noise?

[Cameron 16]

To be perfectly honest, I wouldn't know. I've always assumed it was because of using small pipe diameters, but yeah I know the noise you mean and it sounds awful, like a really high pitched rattling sound. Tailpipe noise is an acoustics thing - i.e. extremely bloody complicated and affected by all sorts of little changes!

 

Using large diameter pipe will give a deeper sound, through some complex witchcraft involving the speed of sound at different temperatures. My 205 uses a 2.5" system and it sounds really nice and deep, but still has a nice little rasp over the top.

[Rippthrough 98]

What causes raspy exhaust noise?

 

Scrutineers with noise meters.

[Cameron 16]

Ah, is it down to people putting restrictors in to meet noise regs then?

[tri_longer 25]

Great job on the spolier, glad you managed to get it to fit ok especially as it was for a different boot lid type.

[wardy18 33 1 Cars]

Yeh it took some re-modelling but it's what the cars always needed so I'm chuffed with it

[wardy18 33 1 Cars]

Ah, is it down to people putting restrictors in to meet noise regs then?

 

I always thought it was due to cheap chav silencers or like on race cars a very straight through systems

 

Well let's pray mine sounds good, I think the 12.5:1 cr will give it some bark

[wardy18 33 1 Cars]

Just thinking forward to engine fitting with regards to mounts, I have seen glimpses of various adaptations that people have come up with and was wondering what's the best set up for a pure race use?

 

Currently I have all std apart froma solid lower engine mount but then there is still a smaller rubber bush in the arm joining the mount to the subframe?

 

Cambelt end mount I have seen 3 arms from the chasms mount location to 3 points on the front of the block and have also seen similar on the gearbox end. I'm a little dubious about completely solid mounting as I don't want to shake the car to bits or my ear drums for that matter.

 

What's the preferred option that people have used?

 

Thanks

 

Simon

[wardy18 33 1 Cars]

Found this info from Magnecor for anyone looking into Ford Coil Packs for an Electronic ignition conversion, has been very useful for me to identify the coil pack i have and also find which HT leads i need to run.

 

I have a 1st Generation coil pack and need Non sealing plug boot HT Leads so MAGNECOR KV85, Part No 45239, 8.5mm Competition Leads.

 

Ford_Coil_Pack_Details.pdf

Edited February 21, 2011 by wardy18

[wardy18 33 1 Cars]

Made myself some new Headlight blanks at the weekend, new improved version that box in the headlight area rather than just a sinle plate with a bracket. Dont worry about the fact the splitter stabiliser bars look pi$$ed, this is because they arnt bolted down in that pic, these are now bolted back in place and also matching mesh has been put in the grills on the splitter at the bottom, ill get some more updated pics asap.

 

[joe1joe 3]

I use uprated mounts and for the little one i used washers top and bottom then welded them so it is solid, but you could always get a peice of material turned down if you wanted to be fancy!

Edited February 28, 2011 by joe1joe

[wracing 19]

i solid mount my engine to the car and to behonest the vibration isnt that bad atall, not really loud you can easly talk to the person next to you.

 

James

[wardy18 33 1 Cars]

What's the advantages of solid mounting?

 

I run the solid lower mount but with the std rubber bush in the arm, the solid mount certainly stops the majority of engine rock as I assume that's the main goal, to allow immediate direct power through the transmission rather than rocking the engine first then moving!

 

How have you solid mounted? Pics if possible please?

 

Cheers

 

Simon

[wracing 19]

I find the gear change is more precise, engine doesn't flap around at all allowing you to be a little lazy on the clearances side of things. as you've said direct application of power rather than the engine rocking. Personally in my opinion I think that its better to solidly mount engines and the only reason road cars are have these sort of arrangements is for ultimate comfort and to make the chassis last 200,000+ miles.

 

You don't see power sources in other high torque applications getting mounted on crappy rubber. Just remember to get your engine balanced well

 

James

[Cameron 16]

You do if it vibrates.

[wracing 19]

lol, I work work with a 630kw machine which is inherently imbalanced you dont mess about you bolt it down and get on with the job

[Cameron 16]

 

Yeah car companies mainly use rubber engine mounts to cut down on interior noise and vibration, if you don't care about either of those things then there's no reason why you can't solid mount an engine.

[wardy18 33 1 Cars]

So it definietly looks like solid mounting is the way forward then, even though im a little dubious over a solid on the gearbox because all you have is a large bolt coming up from the gearbox through a mount, surely this bolt rocks front to back with the engine and so solid mounting this would put alot of stress on the mounts bolts, the mount itself ie opening up the fitment hole, the bolt from the gearbox and more importantly the gearbox casing where the bolt fits in?!

 

Whats the "off the shelf" options for solid mounting???

 

I have seen a few homemade version with bars to various mounting points but i dont have a good machinist on the island so off the shelf or a kind person to copy their version is my only option.

 

Many thanks

 

Simon

[Cameron 16]

You'd have to have a pretty beefy mount for the top of the gearbox, as you mentioned there's going to be a pretty high torque wanting to twist that mount so it'd have to be pretty damn strong. Maybe if you could get a 2nd lower torque mount to tie the bottom of the gearbox in to the subframe it would help things.

[wardy18 33 1 Cars]

So what do people generally do to "solid mount" the engine, is it mainly the rear lower mount (even though the bush in the arm is still rubber and not many seem to solid mount this) and the top mount and leave the gearbox mount as is?

 

Im thinking for the top mount i might retain the std big spherical mount that screws into the chassis the mount it sits on and bolts to and solid mount the bumps stops which bolts front and back holding it in place, so it cant rock but still sits on rubber......

 

Cheers

 

Simon

[edbar 6]

I have a solid alloy large lower mount, nylon small mount (onr that has bolt going through into subframe) and it has snapped the lower fork on my car, granted after probably 1000 miles. It does transmit all vibration into the cabin and this is with my balanced engine assembly. Really need ear plugs aswell as the resonance can be dreadfull! I have also shimmed my top 2 rubbber blocks so it is holding the top arm mount with no room for movement.

[wardy18 33 1 Cars]

Thats exactly how i have run my 205's so far and yes i snapped the arms on the lower mount too, i have now reinforced the new one as to be honest the arm is a little inferior in my view for race application especially. And yes i also packed out the top mount with some hefty spacings.

 

I need a new bush for the lower arm and have a found a company that sells loads of bushes/bearings/mounts etc that look really good, worth a look:

 

www.gmt.gb.com

 

The bush is 30mm OD and 28mm Height so ill phone them and see what they can do, still cant decide whether to go for a rubber bush as std or just solid mount this too so the lower mount will be made up on the large ally mount attached to the engine plus the little ally mount in the arm.

 

This company also seems to sell what looks similar to the 205 gearbox mounts so will have a chat with them.

 

Simon

[Rich_p 23]

Have a read through this thread. It discusses gearbosx mounts and has some pictures

 

http://forum.205gtidrivers.com/index.php?showtopic=117537&hl=richard brent&st=0

[wardy18 33 1 Cars]

Ah ok cheers ill have a read tonight, at the moment i'm having a solid lower arm subframe mount made plus 2 solid bushes to replace the rubber bushes either side of the top mount but will retain the std rubber mount it sits on, will also look into the gearbox mount with either cutting the rubber off and welding in a steel tube but will look into this one, i think as Cameron said for my own piece of mind i would have make up an extra stabilser bar fitted from the underside of the gearbox to the subframe to distribute some of the torque this end of the motor away from the top gearbox mount.

 

Simon