Very upgraded LPG Scimitar MV6 build

[loz]

Finished the Exhaust Manifolds this afternoon

The rest of the system is loosly slid on and it sounds great one Very happy customer. Here's some piccies on the pair.







All the ports inside the manifold are now smoothed out with no rough bits to help things out further.


I took a video of the sound, but the b***dy thing is taking forever to upload, left it overnight and the battery ran out before it uploaded

I'll try again later

[Dropout]

Top work fella, they look great, keep up the good work!

[loz]

Thanks Dropout:)

Finally the video has worked, the picture is a bit dark, but the sound is quite resonable really, it sounds pretty close, just the volume that you can't really get an idea about (its pretty loud though, perhaps a little louder than I'd hoped).

Still, I'm really pleased, it sounds lovely, way nicer than open cylinder heads This is the first time I've been able to rev it right up, I can't believe how quickly it gets up to the limiter, that flywheel is ace!

Video here (click the image):


More to come

[Relentless Rob]

More to come

Supercharger?

[loz]

Its been more than just a passing thought, I really would like to, I think taking the bhp just over 300 would suit the rest of the car nicely, not much more though. I think the next project will be a 3.2 and supercharger, but not till I've had the opportunity to drive it a lot, track it a bit and sort out all the handling properly. Oh and make another brake upgrade for it.

Fingers crossed I might have smoe time on it this weekend, so watch this space.

[loz]

Right guys, a little advice needed, well opinions really. I'm upgrading the brakes again, I can't help myself, and I'm thinking that if its on track getting a full abusing, the current 282mm fronts might start to fade with this new engine so keen to get the car up to speed again (hopefully).... That and I like a project.

I'm getting pushed for time though so I might do the rears now, as I have to make a new caliper mount for the axle and leave the fronts till summer (the brake bias valve weakening the rears for the time being).

I'm thinking 280mm ish vented at the rear.

But before finalising the rear dimensions I need to know what is going on the front before sorting the back. So here are the option I've found that will (just) fit behind the 16" wheels.

Either mk1 Focus ST discs at 304mm

Or mk1 focus RS discs and 324mm

These are the biggest I can find with 4 stud Ford PCD (its ford PCD now for the wheels)

The smaller of the two option is only a slight increase in size from the current 282mm

The bigger ones will clearly be better and disopate heat better, but am I thinking too big. Is the benifit of awesome braking becoming outweighed (literally) by the aditional weight.

I'm still not sure which calipers to go for, bit what are folks opinions on the disc sizes.



Hopefully this thread will light up tomorrow, I'll be starting early and working all day on the car

[owelly]

I fear you may be over-egging the custard with such big brakes on the rear. IIRC 240mm discs are available vented or solid in 108pcd and will be way big enough for your car! After all, your fronts should be doing most of the work so to stop the rears from locking, you'll be 'detuning' them with a bias to the front.

ETA. If the Omega had 285mm (or later, 305mm) discs, why should your lighter car need bigger ones?

[Jaffa]

^^^^^^^^^^^^^

what he said

Size is not everything.

What is the weight distribution like on the car?

Before you change any thing, would it not be better to give it a go first. You may find the rears are already more than you need and you have saved yourself time and money that could be better used.

If during your track time, you fell the fronts aren't up to the job, look those first.

Just a thought

[loz]

Thanks for the suggestions guys,

I guess I feel like the car might warrent bigger brakes because it will be slightly more powerful, and while the brakes on the omega were great, they were not design with track days in mind.

At risk of opening a can of worns....... If you're considering one stopping event from a high speed, the weight of the car is everything. But when cnosidering repeated stopping events time after time after time, then the power of the engine is for more important than the weight of the car. If an engine is able to get a car to a high speed in a shorter time, means that the brakes have less time to cool and will get hotter each time you approuch a bend.

In this situation, the weight of the car isn't significant because you're only considering how much energy the car gathers in a certain distance (before the next braking event).

So the heavy omega might reach 100mph down a straight, lot of brake is needed.

But the same engine in a light car, might reach 120mph down the same straight, therefore the amount of engery (and heat generated) is the same regardless of weight. (with my physics hat on) KE = 1/2 m v^2

If you see what I mean.



The weight distribution of the car used to be 57:43, but I@ve put a much lighter engine in the front, and n LPG tank in the rear so I think it'll be appoaching 50:50. With that and you're comments in mind I think I'll go for the smaller 304mm up front and much larger at the rear (270mm ish).

The old disc conversion I did with 247mm discs was not providing enough force to increase the grip at the front so the fronts were locking very easily, without the car feeling like it was braking much and the rears were very difficult to lock.


Thanks for you suggestions guys.

More to come

[loz]

The exhausts are all done. The angle gridner gave up on me today, so that took a chunk out of the day. Its lasted 5 and its really done well, so I went and bought exactly the same one again (well the new version).

So here are the pipes now conplete with bends in them



Here is how they look on the car





And the whole system layed out. Actually its not quite finished, I still need to just weld the Lambda bosses in, but I'm still waiting for suitable SS versions to turn up.




More to come tomorrow, not sure what yet, but something.

[Buddy]

just read this thread for the first time, a real labour of love, congrats on the results so far, and im really looking forward to the finished car, nice to see the problems as well as the results, makes a nice change

[loz]

Thanks Buddy, its still a way off yet, but I can't wait either

Done some more today, spent a long time tidying up all the welding mess from the exhausts. Its nice to be back onto a list of smaller jobs that needn't take 3 week. After tidying I thought long and hard about how to get the wipers how I wnat them.

The problem is they're slow and the wiper motor is ugly in the engine bay. The two birds one stone answer is to move it into the cab. I bought some more wiper wheel boxes a while ago so these are now fitted, but I've binned the long outer that goes into the engine bay and fitted a smaller section from what was the rear wiper mechanism (now redundent). The idea is that without the bend the wiper motor will not have to overcome the friction in the bend, and will be closer. Ontop of this its all tighter, regreased and the motor has been stripped and cleaned too. It all works a treat.

Here's the new shorter mechanism.


Looking up at the motor in its new home.


The old hole is now filled, but still needs painting.


And the results. In the past if I accidently hit the wipers on a dry day, I'd have to get out and help them accross the windscreen. But now, with dry windscreen and on a pretty flat battery (engine not running too) they're happy to go for it at a resonable pace


More to come, soon hopefully.

[loz]

All painted up now, and the large fuse holder that powers everything accpet the starter motor is now mounted where the old wiper motor would have been.





Just the washer bottle to go back in now.

More to come

[loz]

Its a car day today

All work is done till tomorrow, so I've spent this morning doing lots of research and deciding exactly what brake set up I need for the car. I remember that the upgrade set up I had before was a little weak on the rear. So the fronts would lock up a long before the rears. Now this means that the full baking potential wasn't reached, although they were amazing at not fading. If the rears could have done more work then fronts would have had more grip available so could apply a great slowing force before locking up. Brake ballance is really important so I've done a kind of case study of a selection of cars comparing their weight distribution with their brake power distribution.

Some of the cars on the list are ones I've owned and driven them, and some were picked because they are known to be awesome driving machines, oh and my bro's capri is on there too to check the new set up he's making.

There are a lot of columns for breaking down the calculations, but the first and last two columns are the important ones. You can see that the old Scim set up has a very front strong system at 65:35, and this is why the brakes might not have performed well when really applying the load.



Dam it, the image doesn't seem to fit!, the link is here if anyone wants to look
http://i97.photobucket.com/albums/l217/ ... rCalcs.jpg

The new system will use the Cosworth RS 4x4 273mm rear discs with their original calipers, the front will use the Focus ST 170 300mm discs and Omega Calipers. This combination comes out at a 59:41 front rear bias, which is really close the that of the E36 M3. The other obvious importnat facter is the weight distribution of the car, with the lighter engine up front and the added weight of the LPG tank, battery, Fuel pumps, heavy diff (very heavy), and larger brakes, I would imagine the car is approaching 50:50 weight distribution as with the M3, I'll be checking this asap.

If anyone is interested in doing something like this for an ugrade the info on piston size and everything else was from this website:
http://www.brakepartssuperstore.org.uk/ ... uk/d2.html

So the necessary parts will be in their way soon

Now to the garage to do some real work.

[majic79]

Just thought I might be able to add some info on brakes - rallying and you're not really braking from speed, but you do tend to work them continuously.

Size the brake discs according to the amount of traction you have - if you're running big tyres with big footprints and you can effectively use the traction, then run a big disc - the diameter of the disc affects braking torque.

Size the brake pads according to how hot they get - the heat generated is adsorbed by both pad and disc, but the disc is much better at dissipating heat than the pad. So if you find you have problems with fade (ie, pads overheating and producing excess gasses), the solution is usually to upgrade ventilation and then to try and find a bigger pad, which will in turn return more heat to the disc and reduce fade. This is before looking at tricks like grooved discs which will act to remove gasses and also act like a scour to remove glazing on pads in some cases