The Car Thread

[MadManMike]

That looks nuts - is yours 1zz or have you swapped a 2zz in?

What does it weigh in current form?

[Mark W]

3 hours ago, Adam@TartyBikes said:

I wanted to leave it body-less, but then checked some more TDO's T&Cs more carefully and I think it'll be borderline, and not worth the hassle.

The hassle/looks the OG Munter used to get were bad enough! Can imagine there'd be some sourpusses at a lot of places you'd take it in too in Mad Max mode... Good to see it coming along in any case

[AdamR28]

2 hours ago, MadManMike said:

That looks nuts - is yours 1zz or have you swapped a 2zz in?

What does it weigh in current form?

1ZZ and staying that way. Put waaaayyy too much time and effort into that manifold to swap now

At the moment I'm not sure, perhaps 730kg ish, then likely 750+ once I've added aero bits n bobs.

[SamKidney]

Anyone on here with a motor traders policy? Any recommendations re who to use. 

[MadManMike]

3 hours ago, Adam@TartyBikes said:

1ZZ and staying that way. Put waaaayyy too much time and effort into that manifold to swap now

At the moment I'm not sure, perhaps 730kg ish, then likely 750+ once I've added aero bits n bobs.

Decent power to weight still!

I tell myself I'll keep mine standard if I get one, other than a nicer sounding exhaust and perhaps a little lower, but no doubt I'll end up tearing it apart and sticking a 2ZZ in at some point - The Eunos gave me the confidence to get stuck in to these kind of projects now 

[Luke Rainbird]

8 hours ago, Adam@TartyBikes said:

I wanted to leave it body-less, but then checked some more TDO's T&Cs more carefully and I think it'll be borderline, and not worth the hassle. So the regular bodywork is back on and I've spent the last few days in a YouTube 'race car aerodynamics' black hole, mostly in the hands of Kyle.Engineers, who used to be at Merc F1 apparently: https://www.youtube.com/channel/UCh3tzzP6n5b1EWcMUpiEhXg. Aero is something I've never really bothered with before so it's nice to learn something new! I figure even though the car will be heavier, it will still be ugly as hell and overall faster than no bodywork.

How much left to do on the TT Luke? What sort of spec is that engine that's going in? Looks like it'll be fun for some road blasting!

Good call on the tyres Sam, far too many people stick 888s or similar on kit cars for the road, then wonder why their cars are scary in the cold and damp

 

And because this thread still needs things to look at (this is obviously pre bodywork fitting)...

That looks quick off the mark! Paired with a healthy dose of competent driver that's going to surprise some folk around a track or two for sure!

I like Kyle's vids, they're all pretty well done and he comes across well. He only started them again recently after stopping while at Merc. Clearly knows his stuff, and he was chatting about offering a proper course recently (though I expect it'd be at "F1 aerodynamicist teaches you aero" cost, which rules me out to be honest!)

TT is still a way off yet, which won't be helped by another lockdown which has made work mental. Engine is hung off its own mounts, but the subframe isn't back in yet plus I need to make up a downpipe and a few other bits before I think about turning the key at all. I'm in two minds at the mo - part of me wants to get those bits done, throw the subframe and factory suspension/brakes back on to run the engine in, then work through tidying it all up bit by bit. The other side of me thinks I should do it once and do it right, even if a little slower. Need to get rid of the Leon first really - may pinch the nice bits off it first but not sure (pulled the standalone ECU out the other night, it's got a set of Corbeau seats, and Brembos as standard which the TT didn't etc).

[CC12345678910]

8 hours ago, Adam@TartyBikes said:

I wanted to leave it body-less, but then checked some more TDO's T&Cs more carefully and I think it'll be borderline, and not worth the hassle. So the regular bodywork is back on and I've spent the last few days in a YouTube 'race car aerodynamics' black hole, mostly in the hands of Kyle.Engineers, who used to be at Merc F1 apparently: https://www.youtube.com/channel/UCh3tzzP6n5b1EWcMUpiEhXg. Aero is something I've never really bothered with before so it's nice to learn something new! I figure even though the car will be heavier, it will still be ugly as hell and overall faster than no bodywork.

 

If you're watching kyle engineers then I guess you'll have seen this come up in your feed, and no doubt watched it, but nevertheless;

MOTIVE VIDEO working man's/layman's aero "course"/feature. Featuring yer man's SR22VET S14 weapon.

part one

 

Part the second

 

[Wrayvon]

On 11/17/2020 at 11:53 AM, Adam@TartyBikes said:

Good call on the tyres Sam, far too many people stick 888s or similar on kit cars for the road, then wonder why their cars are scary in the cold and damp

Absolutely! Rainsports have been great for my normal wheels. Of course I have a set of slicks for track use... 

Mr Poo looks fun also!!

[AdamR28]

16 hours ago, CC12345678910 said:

If you're watching kyle engineers then I guess you'll have seen this come up in your feed, and no doubt watched it, but nevertheless;

MOTIVE VIDEO working man's/layman's aero "course"/feature. Featuring yer man's SR22VET S14 weapon

Hadn't seen these - but I have now - thanks dude!

What's 'comforting' is that the theories all the YouTube Experts™ talk about align, hopefully meaning they're not bullshit, ha.

[manuel]

What’s the most efficient upgrade going to be? Seal up/flat the floor and add some diffuser? 

[AdamR28]

Thanks for liking Rowan's post Dave, thats a good clue!

From what I can tell, pretty much in this order... I'm more thinking about drag than lift / downforce, for now anyway.

- Block off excess holes in the front bumper. 

- Vent out of the bonnet.

- Flat floor.

- Diffuser makes a small difference, better if the air gets to it in good 'condition', I won't bother for now.

- Vent out from wheel arches.

- Deflect air away from the front lower faces of the tyres.

- May even add some streamlining (bits of plastic gaffer taped into an aerofoil shape) to the roll bar. The MSA rule book specifically states you're not allowed to do this for competition, so that means it must do something if you do! There's a reasonable amount of CdA going on there (not far off 10% of the total drag of the car, from my maths!) so if I can halve it that'll be a nice easy gain.

But who knows what I'll end up doing 

 

[monkeyseemonkeydo]

1 hour ago, Adam@TartyBikes said:

- Block off excess holes in the front bumper. Sealing panel gaps is always good but on the front bumper it partly depends what the holes are for. The front end is a nice big lump of high pressure so if you can bleed some of that away usefully (brake cooling, venting through ducts to the sides of the bumper etc.) then you can reduce drag by removing some of the surface that the high pressure is acting on.

- Vent out of the bonnet. For cooling? Works best if you duct the flow from the cooling aperture to the rad (diverging as you go so that you're slowing the air to maximise heat loss) then duct from the downstream side of the rad to the bonnet, converging as you go to speed the air back up as it leaves the duct. Little gurney's at the front edges of the exits do a nice job to suck the air out and can add a bit of downforce too.

- Flat floor. Should be a notable drag reduction but be careful not to cook anything by sealing up hot stuff!

- Diffuser makes a small difference, better if the air gets to it in good 'condition', I won't bother for now. Only really works if you can combine it with the flat floor and you can make it extreme enough to do its job. May require reasonably major surgery to the rear end...

- Vent out from wheel arches. Primarily at the top to release high pressure air though this is more lift reduction than drag reduction.

- Deflect air away from the front lower faces of the tyres. Amazing what wheel tabs can do!

- May even add some streamlining (bits of plastic gaffer taped into an aerofoil shape) to the roll bar. The MSA rule book specifically states you're not allowed to do this for competition, so that means it must do something if you do! There's a reasonable amount of CdA going on there (not far off 10% of the total drag of the car, from my maths!) so if I can halve it that'll be a nice easy gain. If you start with a circular cylinder, just adding a flat plate behind the tube of sufficient length (gut feeling would be about one radius plus) will help and reduce drag of the cylinder. Obviously the more aero you can make the shape the better it is.

I love this image:

The two bodies generate the same amount of drag. TL;DR cylinder incredibly bad, aerofoil unbelievably good!

 

 

[AdamR28]

That's all brilliant info Dave, and pretty much what my research turned up just with a few extra nuggets - thanks a lot, really appreciate your input!

The idea behind venting out of the bonnet is to get rid of the air that otherwise would be flying around behind the rad, yeah. I've already found some CFD images from the MR2 and surprisingly most of the bonnet is in negative pressure (I think it's because the 'line' between the bumper and bonnet is quite low compared with a 'normal' car, which seems to have a region of extreme negative pressure right at the front of the bonnet, then transitions to high positive pressure at the base of the windscreen?), so had carte blanche with the vent location. Cut that the other day (and left a Gurney at the front), just needs the ducting finishing now in the style you said.

With the car being rear engine, and just having a few long alloy pipes running from back to front in a small tunnel, there's not too much heat going on so I figure I can seal the floor pretty effectively. To my untrained eye it doesn't look too bad as standard (for an older car), certainly better than a FWD car with no undertrays and an exhaust that runs all the way back, but can defo be improved. There are various 'features' with handy holes already in adequate positions for popping some rivnuts in, so that's the route I'll go.

Looking from the front... appears my car is missing those deflectors / diffusers in front of the front wheels!

And from the back:

The lowest part of my exhaust sits pretty much level with the bottom of the sump, so I'm not sure how much room there is to fit a diffuser. Have chopped a ton out of the rear bumper instead, while still leaving just enough to make it look car-ish

That image is a pretty spectacular demonstration! I had intended to just add a pointy 'tail' to the rear of the roll bar, a bit like the bottom right of the below pic. The tubing is 50mm diameter so with a 100-125mm tail I figure that will reduce wake significantly and should at least halve the drag from the roll cage. And look pretty bloody weird in the process = win.

 

Any thoughts / data on completely enclosing the rear wheels, aka the early Honda Insight? From Ecomodders forum I can see it will drop some drag, but I am wondering if I might run borderline on brake temps if I do that - the car is about 63% rear weighted and the rear brakes carry out a high proportion of the braking! Perhaps just stick with wheel tabs, plus try to a.) keep air out of the arch, and b.) vent the tops like on the front?

[monkeyseemonkeydo]

21 minutes ago, Adam@TartyBikes said:

I've already found some CFD images from the MR2 and surprisingly most of the bonnet is in negative pressure (I think it's because the 'line' between the bumper and bonnet is quite low compared with a 'normal' car, which seems to have a region of extreme negative pressure right at the front of the bonnet, then transitions to high positive pressure at the base of the windscreen?) That's fairly normal to be honest. You get a stagnation point and high pressure right at the front but on any car the flow accelerates rapidly over the top of the bumper and bonnet so you get a nice low pressure (equating to lift of course) over the bonnet with a high pressure area at the base of the screen around the scuttle panel.

With the car being rear engine, and just having a few long alloy pipes running from back to front in a small tunnel, there's not too much heat going on so I figure I can seal the floor pretty effectively. To my untrained eye it doesn't look too bad as standard (for an older car), certainly better than a FWD car with no undertrays and an exhaust that runs all the way back, but can defo be improved. There are various 'features' with handy holes already in adequate positions for popping some rivnuts in, so that's the route I'll go. Sounds good to me. The more you can smooth off and seal the underside the better. As you say, the exhaust basically makes a diffuser unlikely so it's drag reduction more than anything. How does the car handle as standard? I guess being rear engined and RWD understeer and so front grip isn't really an issue as you can sort that on the throttle?

Any thoughts / data on completely enclosing the rear wheels, aka the early Honda Insight? From Ecomodders forum I can see it will drop some drag, but I am wondering if I might run borderline on brake temps if I do that - the car is about 63% rear weighted and the rear brakes carry out a high proportion of the braking! Perhaps just stick with wheel tabs, plus try to a.) keep air out of the arch, and b.) vent the tops like on the front? There's definitely gains to be had from enclosing the wheels but very much at the expense of aesthetics (and brake cooling)! Yeah depending how far you want to go then chopping some of the rear of the arches out to allow air to exit will help and if it's easy to cut a hole and whack some louvres on top of the arches it can't hurt either.

 

[AdamR28]

Thanks again Dave!

Yeah what I was meaning is that the MR2 seems different to most, maybe because of the low nose. A picture will tell it better than my words (the car in the photo has a body kit with a slightly extended 'nose' but not too much)...

Having compared the vent locations on the VX220 and Elise - the closest cars I could find in terms of nose height - they seem to be quite far back, much more so than the pressure plot from a 'normal' car would suggest.

Been trying to work out some CFD software for myself the last few days but not having much lock with OpenFoam or any of the free CAD stuff. Perhaps it's a step too far and will just swallow too much time anyway!

 

The handling as standard is moderate understeer at low speeds and a bit 'agile' at higher speeds. Apparently with the roof on and no spoiler, the rear creates a fair amount of lift (looks like it from the above image too). Obviously this will all change now so I'll have to suck it and see. Hoping the balance will be better having blocked the nose off, ducted it out, and removed the roof!

I can tune handling fairly easily with alignment though. The rear has mild toe out in bump, so running either slight toe in or parallel will give quite different characteristics!

[manuel]

20 hours ago, Adam@TartyBikes said:

That's all brilliant info Dave, and pretty much what my research turned up just with a few extra nuggets - thanks a lot, really appreciate your input!

The idea behind venting out of the bonnet is to get rid of the air that otherwise would be flying around behind the rad, yeah. I've already found some CFD images from the MR2 and surprisingly most of the bonnet is in negative pressure (I think it's because the 'line' between the bumper and bonnet is quite low compared with a 'normal' car, which seems to have a region of extreme negative pressure right at the front of the bonnet, then transitions to high positive pressure at the base of the windscreen?), so had carte blanche with the vent location. Cut that the other day (and left a Gurney at the front), just needs the ducting finishing now in the style you said.

With the car being rear engine, and just having a few long alloy pipes running from back to front in a small tunnel, there's not too much heat going on so I figure I can seal the floor pretty effectively. To my untrained eye it doesn't look too bad as standard (for an older car), certainly better than a FWD car with no undertrays and an exhaust that runs all the way back, but can defo be improved. There are various 'features' with handy holes already in adequate positions for popping some rivnuts in, so that's the route I'll go.

Looking from the front... appears my car is missing those deflectors / diffusers in front of the front wheels!

And from the back:

The lowest part of my exhaust sits pretty much level with the bottom of the sump, so I'm not sure how much room there is to fit a diffuser. Have chopped a ton out of the rear bumper instead, while still leaving just enough to make it look car-ish

That image is a pretty spectacular demonstration! I had intended to just add a pointy 'tail' to the rear of the roll bar, a bit like the bottom right of the below pic. The tubing is 50mm diameter so with a 100-125mm tail I figure that will reduce wake significantly and should at least halve the drag from the roll cage. And look pretty bloody weird in the process = win.

 

Any thoughts / data on completely enclosing the rear wheels, aka the early Honda Insight? From Ecomodders forum I can see it will drop some drag, but I am wondering if I might run borderline on brake temps if I do that - the car is about 63% rear weighted and the rear brakes carry out a high proportion of the braking! Perhaps just stick with wheel tabs, plus try to a.) keep air out of the arch, and b.) vent the tops like on the front?

When you say wheel tabs do you mean some super sexy aero hubcaps? 
 

I love those images of simple shapes and the drag, I also love the uci get around bike tube profiles where you take the bottom right shape and lop the back end off to simulate a more efficient shape that fits into the uci rule box. I find aerodynamics incredibly interesting

[monkeyseemonkeydo]

3 hours ago, manuel said:

When you say wheel tabs do you mean some super sexy aero hubcaps? 

No, afraid not! This is what I mean when I say wheel tabs (though this may be an Aston Martinism...). Having said that I'm pretty sure 'defectors' isn't right!! 

That's from here: https://www.jvejournals.com/article/19210/pdf which shows a pretty significant drag reduction by just sticking 10mm tabs on.

[manuel]

Ah ok nice - in that case - what about some super sexy aero hubcaps instead of closing up the arches? If you are venting out of the top of the arch I doubt it would affect temps at all and should do a little for drag as a cheap easy diy? 

[AdamR28]

Found another paper that agrees with the one Dave posted above, not the same results exactly but a general significant decrease in drag from fitting the tabs / deflectors / whatever: http://publications.lib.chalmers.se/records/fulltext/250512/250512.pdf (page 18 onwards). Note this study uses seemingly less wide tabs, and only fitted to the front.

I think I'll shoot for about 40mm, spanning the width of the tyres, fitted front and rear.

That brings me to another question... the wheel arch pressure plots in the paper above, after adding the wheel tabs, seem to suggest the pressure above the wing is much higher than below it. In which case, would running vents at the top of the wing have the opposite effect and allow air to enter the wheel arch area? Or would louvres / Gurneys sort this out? Appreciate it is a case by case basis but just thinking out loud...

Rowan, I've seen some stuff on enclosed wheels / solid hub caps in my link above, plus this vid below. In short it can help drag but at the expense of brake cooling: 

 

 

[forteh]

All this talk of aero, how much does it scale, if I were to aero the van with knobby tyres, would it make any difference to fuel economy?

For reference the solar panel has a 40mm flat face at the top of the roof above the cab, the roof rack has a bit of a spoiler on the front but it's far from aerodynamic.  I guess a spoiler nose on the front of the panel might help, should I be adding tails to the back of the roof rack cross members.  Or is just going to be wasted effort given that it's a three tonne brick?

[AdamR28]

I reckon you could make a good 5% improvement, perhaps at the expense of aesthetics though - have a look at EcoModders forum for ideas!

[forteh]

An extra 1.5 mpg? Not worth the effort
Also the wife might not appreciate lots of aero bits taped onto the van we're building!  It's not like it's for grip/performance purposes as in your case

[SamKidney]

EG is finally making bigger steps towards being a finished project. 
 

Brackets for the Wilwoods needed some modification to clear the disc. Ideally it would have been nice to utilise a spacer behind the disc to obtain the correct offset but this would have made an already tight set of TD 1.2s and a  225 width tyre a nightmare to squeeze under standard arches without a mahoosive amount of camber. 
 

The engine is sat back in the car with Jenveys attached; one to check ive re-welded the gearbox mount back in the right place, and two to start getting an idea of where the new fuel lines will fit along with the fuel filter. 
 

The engine is coming back out in due course to allow the bay to be painted, and to come back in bits to be rebuild with the ITBs in mind
I have so far acquired: 

- Brian Crower Stage2 Camshafts w. Adjustable vernier pulleys 

- Skunk2 Valve Springs/Titanium retainers 

- Skunk2 H beam rods w. ARP Hardware 

- Wiseco 11.7:1 Pistons/Rings and pins 

- OEM head gasket 

- Supertech flat faced valves 

- Supertech valve guides 

- Fidanza two piece flywheel 

- Exedy Stage1 clutch 

- ATI Flui-Dampr crank pulley

- King race bearings big end and mains 

- TODA billet oil pump gears and shims 

- Baffled sump 

- Walbro 255 in tank pump 

Management is via a Hondata S300 V3 ECU. 

Gearing is by means of a DC2 gearbox with the following: 

- MFactory 4.982 final drive 

- M Factory short 4th and 5th gear 

- Spoon 1.5 way plated LSD

Hoping it can see somewhere in the region of 220-230bhp at a peak 9500 rpm. The ITBs should help make some power low down though I have spoken to Jenvey and they’re able to provide custom length trumpets to help tune air resonance should they be needed. 
 

 

 

[CC12345678910]

On 11/18/2020 at 6:55 PM, Adam@TartyBikes said:

Thanks for liking Rowan's post Dave, thats a good clue!

From what I can tell, pretty much in this order... I'm more thinking about drag than lift / downforce, for now anyway.

- Block off excess holes in the front bumper. 

- Vent out of the bonnet.

- Flat floor.

- Diffuser makes a small difference, better if the air gets to it in good 'condition', I won't bother for now.

- Vent out from wheel arches.

- Deflect air away from the front lower faces of the tyres.

- May even add some streamlining (bits of plastic gaffer taped into an aerofoil shape) to the roll bar. The MSA rule book specifically states you're not allowed to do this for competition, so that means it must do something if you do! There's a reasonable amount of CdA going on there (not far off 10% of the total drag of the car, from my maths!) so if I can halve it that'll be a nice easy gain.

But who knows what I'll end up doing 

 

Slight backtrack in topic timewise I know but I've been offline so sue me.

Do you have room in an MRS to do a (FC/FD RX7 esk) V mount of flat mount rad in the front? Then duct the airflow through, say a half size civic style ally rad (can you weld ally? You could go with a 3-4inch thick ebay core and make end tanks to fit...) and into a BFO set of origin/dmax/RE Amemiya/Pandem/2 dozen other bugger's style bonnet louvers? (nowt fancy like, just thinking couple grinder slits wit' 9 inch/stihl saw through the frunk then bent up with moleys/vice grips/channel locks, patch triangles tacked in at' sides and then possibly [fiber] 'glassed over to look like something - side ducting undert' frunk between frunk and rad could be plywood even, then seal the join between the frunk and your ducting with glazing tape)

 

 

The article that pic is from is here http://www.speedhunters.com/2013/02/true-dedication-under-suzukis-s15/ 

('as ye seen da size of dem tunnells boi?)

I'd just take the scorch racing s15 as the instruction manual if I was in your position, and have fun with how ghettopikey I could get away with being whilst trying to copy/implement some of it.

There is a pic somewhere of Under Suzuki crouched inside of one the tunnels after he [they] hacked out the back some more and went pushrod cantilever suspension but I couldn't recall where to find it.

If you look at that ^ piccy there anything air that doesn't go though the rad and vents goes through mesh in the back of the box 'til it hits the (what happens to be inclined sheet metal in that car) firewall at which point it is told to get the f**k into the the tunnels.

That seems to be the rule of thumb; if you absolutely must let airflow go through the car rather than over it get it collated, bitched into submission and ejected the f**k out faster than an senna infused E coli vindaloo. Be that louvers, arch cut outs, flat floor yada yada.

The only difference to me is that you and @monkeyseemonkeydo can put it in maths and shit whereas I was deemed too dumb to be taught all that stuff in school 

Edited December 1, 2020 by CC12345678910

[MadManMike]

No project / fun updates from me yet, but my new company car arrived today and I waved goodbye to the 120d...