MK1 R32 4-Motion Sport

[Dub Toffee]

[HaydEn]

Absolutely amazing.


"I only post on Facebook if I know i am going to get likes" - M

[paintz]

keeping busy ben.

[Dub Toffee]

cheers lads

was looking into Aerodynamics for the Caddy and at first searched for -wind tunnel UTE- and Utility - then realised more has been done in America etc and searched under -Pickup-!
It looks like their has been allot of Myth surrounding wether or not to have the tail gate down.
The Myth is that having the rear tailgate down makes you more aerodynamic. It stands to reason by basic observation that it might be the best option but testing shows
If the Tail is left up it creates a relatively stagnant pocket of air inside the Tray. This pocket allows the air riding over cabin to continue in a nice path over the tray and over the tailgate!
Myth busters did a test with identical pickups and traveled over dessert with them. One tray down the other tray up.
The Pickup with the tray up went 50km further before it ran out of fuel.

looking at wind tunnel photos comparing a pickup to a Sedan you can see that their is not allot of difference in the overall flow of air over the vehicle.

I cant find any tunnel tests comparing a pickup with a cover over the tray and one without.

Interestingly a study has this to say
" Velocity field measurements of the near wake flow show a relatively quiet region behind the cab and no recirculating flow region in the symmetry plane behind the tailgate.
Instead there is a strong downwash at the symmetry plane behind the tailgate. This downwash is due to the existence of a pair of counter-rotating vortices downstream of the tailgate.
The downwash promotes attached flow behind the tailgate, thus resulting in a pressure recovery that reduces drag. " thumbup:









here are some of the articles i came across have fun :popcorn:

Tailgate: Up or Down? | Symscape

Driving With Tailgate Up Is Fuel Efficient : Discovery Channel

Experimental study of a pickup truck near wake

GMC shows off slicker 2014 Sierra 1500 Regular Cab pickup - Kelley Blue Book

[slowmotion_93]

...wow.

Subscribed :O

[Peter Jones]

You might want to have a think about the underside too.

You've got a lot of weight over the front end but you might still experience lift at high speeds if you're going to track the car.

MK1s take off at about 200Km/h. Up to about 180km/h is OK with typical MK1 front profile.

[Dub Toffee]

So mk1's want to fly sometime after 180+ km/h !
has anyone studied it?
I was hoping to do some top end speed trials with the Caddy on a long run but i will be cautious about it now.
Would be great to find out what an ultimate Aero package for a mk1 would be!
Especially underneath. I am wondering if the Caddy being longer than a hatch mk1 affects
the figures above on a mk1's top speed for better?
I want to get to work with an approach similar to the mk2 RWD16v that was being built and showcased onVortex.
His work under that car was good, sheeting everything off.
Will be looking into what the effects are of having fins out the back like you see on the rear end/rear underside of track cars .
aside from that I experimented once with making my own surfboard fins and discovered a little bit of fin goes a loooong way!

[gldgti]

cheers lads



Interestingly a study has this to say
" Velocity field measurements of the near wake flow show a relatively quiet region behind the cab and no recirculating flow region in the symmetry plane behind the tailgate.
Instead there is a strong downwash at the symmetry plane behind the tailgate. This downwash is due to the existence of a pair of counter-rotating vortices downstream of the tailgate.
The downwash promotes attached flow behind the tailgate, thus resulting in a pressure recovery that reduces drag. " thumbup:

This is the same kind of aerodynamic concept that was utilised on the Mk1 hatchback - the inset rear window causing vortexes to shed at the back aiding attached flow at the very back of the car.

Good for economy, not ideal for downforce though

The trans tunnel looks amazing man. I can't believe its on its wheels!

[Dub Toffee]

thanks mate, thats interesting info on mk1 Aero
wouldn't it be great if someone with money in the UK etc messed about with mk1's a wind tunnel and building a competitive Aero package

[gldgti]

thanks mate, thats interesting info on mk1 Aero
wouldn't it be great if someone with money in the UK etc messed about with mk1's a wind tunnel and building a competitive Aero package

I would have thought probably the kamei kits would have been well researched in their day. Front end aerodynamics of cars, in sofar as the knowledge possessed by designers, probably hasn't changed a great deal in 30 years. However, what happens at the back and underneath has certainly advanced a lot - so you are right on the money in terms of looking into underbody and rear diffusers.

Also, I think they have a nascar truck series in the US..... IIRC, they have some very 'agricultural' looking aero devices that are in fact very effective.

[Dub Toffee]

yea i seen the nascar ones and its just as you said.
I mentioned on vortex a while back and realised i didnt put it on here but i was looking at
the idea of playing about with ballast in rear. If its not to much extra weight the benefits of cornering
with a more equally balanced vehicle might out way a small loss of acceleration.
IM keen to see how 4-MOE goes with wide tyres!

[gldgti]

yea i seen the nascar ones and its just as you said.
I mentioned on vortex a while back and realised i didnt put it on here but i was looking at
the idea of playing about with ballast in rear. If its not to much extra weight the benefits of cornering
with a more equally balanced vehicle might out way a small loss of acceleration.
IM keen to see how 4-MOE goes with wide tyres!

The HSV Maloo (VE) has 50kg of ballast at teh rear axle.

[Dub Toffee]

What!
I mean its something i have seen in Ship building and aerospace but not production cars.
I guess the fat Auzzie business owners that i seen drive them have a good reason to loose 50kg haha
the Maloo is a brute tho and at least holden have got out some iconic cars before volkswagen take over the world haha

[gldgti]

True!

Having only been a passenger in one I can only give a rough indication, but I would have said it was a worthwhile, if a bit silly, addition to the maloo. It certainly seems to have better handling balance than the SSV, etc. Way more rear grip than I thought it should have, anyway. Then again, 275 rear tyres are also pretty huge.

Regardless, I think the caddy will be leaps and bounds ahead, given the lovely 4-mo drivetrain

[sports racer]

Back in the Dark Ages when I was a lad we found that the old Holden HR ute would handle heaps better if there was a hay bale in the back.

The only thing we knew about weight distribution back then was never give a lift to a fat chick if you wanted to set a good time between Katoomba and Lithgow.

Cheers

Paul