1971 Capri Trackcar - always check your pins!

[MaxN]

Jun 2, 2014 12:04:10 GMT PhoenixCapri said:

Have also cut out the rear of the bonnet bulge to try and help get hot air out of the engine bay. Not really critical, but since I'm planning a flat front floor at some point, it made sense to open it up now while I'm messing around with the bonnet anyway.

I may be completely wrong here, but I am reasonably sure that the area at the bottom of the windshield is a high pressure zone and as such this will mean that rather than allowing hot air to escape, it will push air in through that new hole. 

It might be different for Capri's, but my local mustang racers use similar holes to feed the carbs nice dense, high pressure air.....

[PhoenixCapri]

Jun 4, 2014 12:12:54 GMT MaxN said:

I may be completely wrong here, but I am reasonably sure that the area at the bottom of the windshield is a high pressure zone and as such this will mean that rather than allowing hot air to escape, it will push air in through that new hole. 

It might be different for Capri's, but my local mustang racers use similar holes to feed the carbs nice dense, high pressure air.....

You're quite right actually, and to get it to work to draw the hot air out will take quite a bit higher pressure on the engine bay side than you'd see normally, or I'll have to find a way to create some lower pressure at the base of the screen.

A pretty picture of the effect:

link

Sadly there doesn't seem to be a nice picture of the aero pressures of a Capri on Google (how odd?), but this is sort of similar, if you squint, a lot. It does have a budged bonnet, so sort of shows the effect there, kind of...

It's clear that at the front of the engine bay (radiator grill) the pressure is higher than at the base of the screen behind the bulge. A flat floor, and thus pretty sealed engine bay might thus deliver higher pressure on the engine bay side than the bottom of the screen. Then again forcing the air to navigate a radiator pack, fan and dressed engine will probably cause such high pressure losses that it might not...

It's something I'm going to have to play with if I'm honest. I suppose I could add a small flip up spoiler to the rear of the power bulge, this might help to direct the air up the screen, creating a lower pressure area around the opening at the back of the bonnet. Or I could create a nice cold air pickup from back there. To be honest just about every bit of this car is going to be pretty much a development vehicle, and I'm sure there'll be plenty wrong with it when I start to understand how different areas are working!

Time to buy some cakes for the aero team down the other end of the office perhaps!

[monkeep]

Man, this is coming together pretty flippin' fast...!!

Info from the car's past sounds like it could be pretty colourful, how long had it been racing for??

[PhoenixCapri]

Most of one race!.....

[monkeep]

I bet it feels good to finally be able to sit in it at last and get a feel for how it is coming along!!

From that photo I have to say - I never realized just how big those boxes were for the rear suspension arms - they are properly massive...!!

Otherwise, it looks like its coming along nicely, those fiddly brackets look, well, fiddly! But also very tidy, I bet you'll be glad once they're done...

[bstardchild]

Nice to see this bounce up in my bookmarks not sure why I missed it earlier... Clever and simple stuff in places and as usual always something to learn from your posts/threads

[PhoenixCapri]

Cheers guys and the boxes are pretty big aren't they - just standard Grp4 Escort boxes though. Might be because the seats are pretty small really (certainly can't start enjoying beer and pies too much!)

[rob0r]

Great stuff awesome workmanship

[PhoenixCapri]

Cheers dude

Last nights end of day chill with red wine also included knocking a wider grill together to account for the smaller and wider set headlights.

Take some plastic extrusion -



Grab the hot air gun and make thinks bendy enough to set them to a new shape



Attach to some L-section bits notched with the right spacing



Glue it all together, and eh voila



Now I just need to get it on the car and trim the ends to fit around the headlights nicely

[monkeep]

As far as I understand, going from rubber mounts to solid mounts shouldn't make your steering go from stable to "jittery", that sort of change would only be caused by changing the wheel alignment (more toe-in on the front e.g.).
It should make the steering feel less soft / more direct and therefore transmit more feedback. On the flipside, more feedback can mean more vibration (as I'm sure you know already ;-)) but hopefully it shouldn't be too bad on smooth racetracks... As a point of note, classic Mini's have solid mounted steering racks from the factory (u-bolts through the bulkhead...) and you know the steering feel is pretty direct on them :-)

Otherwise I think the ride height is pretty good for a first estimate, should give a decent amount of suspension travel. Are the springs brand new? because they will probably settle a little once the full weight of the car is on them... That is all adjustable anyway so if it does look a bit 4x4 you can just get the c-spanners out and slam it whenever you feel like it!!

With the suspension and steering all together it looks like this will be a rolling shell in no time at all, you will need that engine crane shortly by the looks of things!!

[mwggriffiths]

Jun 25, 2014 11:45:39 GMT PhoenixCapri said:

Also got the rear axle all built up - have a pointless piccy of the diff that my inability to control properly probably caused me to write off the poor old Escort!

This cannot possibly go wrong.....

[PhoenixCapri]

Exactly, it'll be fine ;D

[Alex1380]

The Zetec looks lost in that big engine bay, almost enough room for two!

[PhoenixCapri]

I may have noticed that myself.... clearly a V8 is needed at some point!

[monkeep]

looks like its coming along nicely, out of interest, where would you rather have put the strut brace? It looks a pretty good position already and if those brackets are welded to the body it will be flipping rigid anyway...!

Am I right in thinking that now the front struts are on and the rear brakes are fitted you could effectively have a rolling chassis (obviously if you didn't still need to fit the engine)? That's got to give plenty of "feel good factor" knowing that you could theoretically put it back on its wheels if you wanted to!!

Windows are overrated, you've got a full face haven't you?? :-P

[monkeep]

Jun 26, 2014 12:22:33 GMT PhoenixCapri said:

I may have noticed that myself.... clearly a V8 is needed at some point!

I thought this was part of the plan in the first place? Hence the chassis strengthening and so on...

[PhoenixCapri]

Jun 26, 2014 12:27:25 GMT monkeep said:

Windows are overrated, you've got a full face haven't you?? :-P

Now ^ this is a very good point! Plus it's got a windscreen so the rest is just dead weight really

Strut brace wise I'd have quite liked to have got it directly between the strut tops, but the bar would need to be shortened a bit, and the coolant pipe is also in the way.

And maybe not a V8, but definitely something with more power (300-350bhp) I think I'd envisioned a turbo 4 pot, but V8 would obviously be better!

[monkeep]

Looks good, I like the nice clean look to the front end with the hidden indicators :-)

I can't decide whether it is a smiley face or an angry face, I think once the bonnet is on it will definitely be the latter but I like to think the Capri is happy to be making such good progress and so is presently smiling :-)

You already have a lower air dam ready to go don't you? That will definitely make it look more aggressive...

[daftmonkey81]

love the running light/indicator idea. looks top notch!!

great build so far!

[The House]

Man I love this build.

Love the idea of a high power turbo 4 pot, like a throwback to the Wurth Zakspeed Capri. 1.4 4 pot turbo making 450bhp at 9200rpm. I can appreciate that this possibly wouldnt quite be so extreme, but I still think turbo 4 pot is the way forward!