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V8 Fauxrrari

13K views 29 replies 10 participants last post by  Jared 
#1 ·
Howdy folks, thought some of you may be interested in my little swap.

Picked up this shell in exchange for my old V6Roadster from Mister Woods.



(Note, photoshopped to sit right, it's like a ruddy tractor right now)

The idea here being to get the engine in with the new Audi gearbox and not have to cut any firewalls other than the boot.

So...out with the angle grinder.



 
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#2 ·
And sling the gearbox in to do some measuring up.







Now the issue is whether or not the driveshafts will pass the subframe or not without pushing the engine too far forward.

The fuel filler pipe will need moved down a bit to avoid the left head and it's going to be fooking close but i'm 99% sure this is gonna work pretty straight forward.

Subframe will be notched to allow it to sit a little further down and then i can mount up the gearbox and see if the engine will slide in in front. Time to make some sacrifices to the Flying Spaghetti monster
 
#4 ·
What's the measurement from the bellhousing face to the firewall?

For those that may not know, the firewall is sloped (not vertical), and the bottom of the firewall is furthur away from the rear of the car than the top, so the top front of any engine used (heads & valve covers possibly) could interfere.
 
#6 ·
At the moment, i'm working off 490mm from the bellhousing face to the front pulley. In the pics that is 490mm from the bellhousing face to the fuel filler pipe.

So when i move the fuel filler pipe lower and bypass the heater pipes from hell then there is a good few cm's to play with at the front. Even taking in the slope of the top of it and the fuel tank breathers it might still fit without too much hassle.

Even if i have to relieve the firewall a touch it won't be an issue.

There's a bit of trimming to be done on the subframe front edge and i'll also sink the gearbox as low as possible into the subframe.

It'll be tight but i reckon it might just work. Trying to get my head around the driveshaft up/down limits at the moment. Just how much range of movement do i need there?
 
#8 ·
It's an Audi OB1 gearbox and an AHC engine i'll be using.

The flywheel and clutch are quite a clever arrangement, atm i haven't researched it completely but Paul assures me it will work and for some stupid reason i trust him.

From what i can see the clutch and flywheel sit beyond the driveshaft and then bolt to the engine crank by a spigot.
 
#9 ·
It looks to me like he's using an Audi box, and is planning to use an Audi V8 (which are the shortest of the easily obtainable V8's made). 490mm is about the length of the Audi V8's.

Audi ran the front axle through the bellhousing to get the engine overhang to be as small as possible. They insist on a longitudinal layout, even in their FWD only cars, just like thier AWD cars, like a subaru and unlike say, an EVO, or Celica All-Trac. Unlike the japanese cars, Audi puts the diff on the right side of the bellhousing. You can see it in his photos. Please note that this arrangement is Audi's newest. The older Audi FWD gearboxes (that are easier to find in the states) do not run the intermediate shaft through the bellhousing, and the axle centerline is aft of the bellhousing. I'm not sure what year they switched to the new arrangement. OberJ can let us know, and I believe its a Europe only deal.

He will have to use an OEM style clutch and flywheel, which are made to clear that front axle intermediate shaft.

Olber: I found that removing the heat sheild from the MR2 firewall, removing the fiberglass, and removing the Vent tube/vapor expansion tube from the firewall allowed me to move my engine MUCH further forward. YOu can remotely locate the tubes somewhere else, as they are coupled to the MR2 gas take via rubber hoses. The fuel filler is a little trickier, as you will need to make a new one, and route the rubber connecting hose to a different location, and you will probably need a longer hose.

I think these are better options than cutting the firewall. Also, the lower section of the firewall (where the stock MR2 front mount attaches to the car) is an integrated crossmember--its structural, so I strongly recommend not cutting into this.
 
#10 ·
OlberJ said:
It's an Audi OB1 gearbox and an AHC engine i'll be using.

The flywheel and clutch are quite a clever arrangement, atm i haven't researched it completely but Paul assures me it will work and for some stupid reason i trust him.

From what i can see the clutch and flywheel sit beyond the driveshaft and then bolt to the engine crank by a spigot.
Yes, that's correct. The flywheel and clutch are AFT of the jackshaft. There is a very thick, but small diameter spacer between the crank flange and the flywheel.

I assume you live in the UK or europe?
 
#13 ·
Yeah i've seen that. Liked the build but couldn't go with the whole cabin intrusion or equivalent chassis stretch at the rear.

If this goes in as i think it will, it'll get a lot of attention from the kit car boys i think. How many 355/360/430 Mk2 kits are out there?
 
#15 ·
OlberJ said:
Yeah i've seen that. Liked the build but couldn't go with the whole cabin intrusion or equivalent chassis stretch at the rear.

If this goes in as i think it will, it'll get a lot of attention from the kit car boys i think. How many 355/360/430 Mk2 kits are out there?
I understand that perfectly. For my own project, minimal to no cutting of the car body was the goal. I am pretty sure the Northstar + F40 goes into the mk2 chassis without cutting anything major. May need to hammer a couple of "clearance dents" in a couple of places, and the X-member needs to be cut some. But the X member is easy to replace, so in theory, I can go back to stock if I want to.
 
#16 ·
Ha, is it?

Oh dear, the old man came out with it one night when we went to look at the car and it just kinda stuck.

I'm removing all the badges and making it into a prototype/challenge spec looking car to try and get away from the whole replica thing. It's a nice shape but it's not a Fezza and i'm not trying to kid anyone on it is.

 
#22 ·
cbulen said:
Gouky, that is an AWESOME custom crossmember! Way better than the one I tried to build (but ended up figuring out a way to use the stock one).

I'm not sure your CV joints are going to last at that angle though.
they won't last 200k miles, but they will last at least 60-80k

they are well within their limits and while i haven't put more than a few miles on that vehicle because of other issues i've done it on other ones before without issue. it's no worse than a normal 4x4 SUV that uses CV joints at the wheel.
 
#25 ·
Do you happen to know if it uses the same gears as the later awd trannies? Because if so, the RA spec gears are stronger and could go in, which tend to handle about 300 ft/lb before reliability is too terrible. Stock wrx gears seem to be 250 ft lb, except for the last few years they updated the 5 speed to use the RA type stronger / wider gears, and obviously the 6 speed from the STI is a different beast - terrible ratios for drag racing, but the only affordable manual option for subaru people that handles big power
 
#26 ·
Jared said:
Do you happen to know if it uses the same gears as the later awd trannies? Because if so, the RA spec gears are stronger and could go in, which tend to handle about 300 ft/lb before reliability is too terrible. Stock wrx gears seem to be 250 ft lb, except for the last few years they updated the 5 speed to use the RA type stronger / wider gears, and obviously the 6 speed from the STI is a different beast - terrible ratios for drag racing, but the only affordable manual option for subaru people that handles big power
i would not be surprised if many of the parts were interchangable. it's the same transmission code.

but why do you ask? I'm actually done with that transmission and crossmember. the car is getting a different set of engines and a completely different drivetrain assembly soon.
 
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