[woosht]

Add me to the list of folks who registered for this site just to post in this behemoth of a thread. Fantastic project, fantastic documentation, great fab skills and the engineering is tip top. I'm about to go read a bunch of other motorgeek project threads (but doubt they'll be able to match this one)

cheers!!

 

[hilly]

I have just had a look at that Jalopnik thread, it is all very humbling, I am not that good honest, I am just a bloke with a few tools and a driveway........

Hilly

 

[cuatrokoop]

I'm about to go read a bunch of other motorgeek project threads (but doubt they'll be able to match this one)

cheers!!

What, not impressed by 3.6L/4.2L V8tt's, 700+ whp quattros, SWB Fox 20vt quattro, etc? Sure, Hilly's car was done very well but there are others that are also done well.

 

[hilly]

I'm about to go read a bunch of other motorgeek project threads (but doubt they'll be able to match this one)

cheers!!

What, not impressed by 3.6L/4.2L V8tt's, 700+ whp quattros, SWB Fox 20vt quattro, etc? Sure, Hilly's car was done very well but there are others that are also done well.

Absolutely !!!!!!

Hilly

 

[derracuda]

I'm about to go read a bunch of other motorgeek project threads (but doubt they'll be able to match this one)

cheers!!

What, not impressed by 3.6L/4.2L V8tt's, 700+ whp quattros, SWB Fox 20vt quattro, etc? Sure, Hilly's car was done very well but there are others that are also done well.

obviously a lotus Elitist

 

[hilly]

obviously a lotus Elitist

Oh dear.........................

Hilly

 

[cuatrokoop]

Or a Lotus Espritist :wink:

 

[woosht]

what makes this thread impressive is not just the admirable undertaking, the dedication, or the execution. it's the documentation. I've swapped a couple motors (little brother's 1jzgte into his lexus sc300) and to take the time to photograph all the tough bits for posterity is what really makes this one great

...that and the lotus ;p

 

[derracuda]

yeah, i have to admit that Hilly leaves me a bit envious in the documenting part, and machining part, and the running V8 part... *sigh* dang it, now i feel worthless!

 

[vwdevotee]

I loved reading about your build. I look forward to reading about your next project. I had a couple of questions I was hoping you could answer.

Did the trans bolt directly to the engine? Other than the pilot bearing issue, was there any problem?

How well does the trans hold up to the power of the V8? I'm pretty sure all of the V8's in the states get Quattro.

What kept you from just using the Audi ECU and wiring harness instead of the custom (which was incredibly cool by the way)?

I'm sure I will think of more tomorrow, but that's it for now. Thanks for everything.

 

[hilly]

Did the trans bolt directly to the engine? Other than the pilot bearing issue, was there any problem?

Yeap, the engine and gearbox bolted straight on.
Not all the holes lined up, but from memory there were 8 bolts ( 7xM10 and 1xM8 ) that did so plenty strong enough.
Other than making sure the spacing of the alloy flywheel was correct to ensure the starter engaged with the ring gear properly, no problems at all.

How well does the trans hold up to the power of the V8? I'm pretty sure all of the V8's in the states get Quattro.

I haven't blown it up yet.......
I don't dump the clutch in first (it spins up the rear wheels in the dry in first anyhow) so I am fairly sympathetic to it. The 01X is hung on the back of the 2.7 V6 A4/A6 diesel which generates 280ft/lb which is only slightly less than the standard ABZ, so it should hold up OK as the Lotus is a fair bit lighter.

What kept you from just using the Audi ECU and wiring harness instead of the custom (which was incredibly cool by the way)?

I did keep the wiring harness un modified, but I ditched the Audi ECU for a number of reasons.
First it comms with the auto gearbox ECU (which I don't have) and therefore throws a fit.
It also uses a AFM which would have been a pain in my application.
Most important was that fact that by swapping to an after market ECU (VEMS) I could tune the ECU to the engine as it was far from standard (no cats, totally different exhaust layout) and get the most out of it.

Hilly

 

[vwdevotee]

Other than making sure the spacing of the alloy flywheel was correct to ensure the starter engaged with the ring gear properly, no problems at all.

Would you mind sharing that spacer thickness? I'm looking for an engine and trans now, so getting that made before hand would speed stuff up for me.

I did keep the wiring harness un modified, but I ditched the Audi ECU for a number of reasons.

That would explain desoldering the big plug off of the Audi ECU. I get it now.

It also uses a AFM which would have been a pain in my application.

Perhaps this is my Yankee ignorance (or just my general ignorance), but what is AFM?

Just curious, have you rolled into an Audi dealer for service yet? I'm curious how they reacted.

 

[cuatrokoop]

AFM = air flow meter unless my brit to yank is messed up.

 

[hilly]

Would you mind sharing that spacer thickness? I'm looking for an engine and trans now, so getting that made before hand would speed stuff up for me.

Can't remember what the thickness was unfortunately, but it was only something like 3.0mm.
I used the spare 10 hole washer plate thingy that holds the flex plate on from the wrecked engine.
I did mic it up to make sure it's thickness was consistent all the way around to prevent run out, I just didn't note it down anywhere.

Just curious, have you rolled into an Audi dealer for service yet? I'm curious how they reacted.

As it happens no I haven't, I have a feeling they won't be able to look it up in their service books........

AFM = air flow meter unless my brit to yank is messed up.

That is the same conversion book I am using

Hilly

 

[hilly]

Time for a bit of an update.

The power steering is all in and working and I have managed to re-assemble the dash as well.

I got hold of a Vauxhall surround for the column (tip here for anyone doing a electric column conversion, just buy the surround from a dealer as it is only £13) and chopped it about a bit to fit the Lotus.

I still need to make a couple of panels to hide the wiring's modesty (and sort out the ropey carpet), but other than that it is done.

As this is a long term project I need to keep coming up with stuff for the updates.
I have been driving around for a few weeks now so it is time to start sorting out some of the conversion problems.

The biggest problem at the moment is cooling, no big surprise in a mid engine application.

I actually have 3 problems, expansion, under cooling and under heating if that doesn't sound too odd.....

1) Coolant expansion.
I was pretty limited with the space and location for the coolant heater tank.
The alloy tank I fitted looks nice, but just isn't big enough.
This is due to the coolant pipework from the engine at the back of the car all the way down to the radiator at the front.
On the A8 this distance is about 1 foot, on the Lotus it is getting on for 10 feet.
All this extra water in the system means that due to expansion, the change in coolant level from cold to hot is greater than the capacity of the header tank, not good.
As I can't fit a bigger tank (there just isn't room) then I'll have to install a secondary tank which can go pretty much anywhere in the engine bay. The hunt for a suitable tank begins.

2) Under heating.
The Lotus interior heater matrix is hooked up to the outlets on the ABZ pipework and it all works fine (i.e. nice and toasty in the car when driving) except when idling.
In this case the heater soon starts blowing cold air which heats up again if the engine is revved, indication a lack of flow.
Not sure if the A8 has an electric pump in the heater pipework (anyone confirm???) and without it there just isn't the correct coolant movement especially as the pipework is probably 10 times the length in the Lotus as the A8 .
To get around this I have fitted a small pump which should keep the coolant moving. As per usual it wasn't quite as simple as I had hoped because the fittings on the pump were bigger than the Lotus hoses.
So I knocked up a couple of reducers out of alloy.
Here is the little pump (as it happens, an Audi one) and adaptors.

A little bit of hose cutting/wiring and it is soon mounted in the LH rear wheel arch.

Fired up the engine and plenty of hot air appears even when idling, brilliant for keeping the screen defrosted just in time for summer

3) Under cooling.
Now this one is a bit more serious.
Again, everything is fine when the engine is at a decent amount of revs, it all goes pear shaped when idling as the coolant flow through the rad drops. Not dangerously low, but enough to make me do something about it.
If I go for a bit of a run and then get stuck in non-moving traffic the temp will rise and the fans come on like they are supposed to.
However the temperature won't come down, it just holds it at 95°C unless I rev it a bit.
The water going into the rad is hot, but comes out stone cold so there isn't a cooling problem, circulation is the criminal here.
This is only going to get worse when summer kick in (what am I talking about, it only ever rains here in the UK) so this needs fixing.

I think the radiator and pipework (see problem 1) plays a part in this.
The A8 radiator is about 1 metre wide and 600mm high where as the Lotus rad is longer (1.5 metre) and lower (450mm).
The cooling area is about the same, but the longer and fewer cores of the Lotus radiator are causing an increased flow restriction.
This reduced flow together with the extra piping is more than the mechanical water pump was designed to deal with.
Now there could be a fault with the water pump (and could be related to problem 2), but it works fine at higher engine speed, so probably not.

One other thing that is not helping is the oil cooler.
I had to ditch the Audi water-oil cooler for space reasons and have fitted a Mocal unit.

When stationary there is no air movement through the cooler so it isn't doing anything to help where as on the Audi water unit would still be cooling.

So the plan is to fit a big fat fan onto the oil cooler linked to the rad fan circuit and see what happens. With a bit of luck this will provide enough cooling to take some of the load off the rad.

If this doesn't help enough then I'll either have to begin looking at the mechanical pump for damage or investigate an electric cooling pump which is less than ideal.

Hilly

 

[cbulen]

The MR2 turbo has 4 coolant pipes from the engine (two 1.25 inch diameter pipes to the radiator at the front of the car, and 2 smaller pipes -- roughly 5/8 inch, to the heater core in the dash). I am not sure if the water pump on the MR2 engine (the toyota 3S-GTE) is any different than a standard Toyota pump meant for a front engine application, but MR2's have no problems with cooling when everything is in good repair. I am pretty sure the MR2 non-turbo -- using the Toyta 5S-FE from the Camry, is the same as the Camry engine. I wonder why you are having coolant flow issues. I might have similar problems with the Audi ABZ.

We expected some problems, and I anticpated needing a new radiator as my MR2 system is designed to cool a 200 hp 2.0liter 4 cylinder motor, rather than a 4.2 V8.

Perhaps larger coolant pipes and hoses from the engine to the front of your car will help with the flow restrictions, even if it necks up/down at the engine and at the radiator. If I recall correctly, in my fuild dynamics class, a smaller pipe has more interior surface area relative to the amount of liquid flowing, so long skinny pipes create a lot more drag than larger long pipes that end up necking down and up at the ends.

 

[a4kquattro]

suggestion: go with an electric "helper pump" for the main lines going from the engine to radiator. I bet that will solve your problems (and you will be able to get rid of that small electric pump to supply your heater core).

Something like this (pic link goes to summit racing catalog page):

 

[hilly]

The MR2 turbo has 4 coolant pipes from the engine (two 1.25 inch diameter pipes to the radiator at the front of the car, and 2 smaller pipes -- roughly 5/8 inch, to the heater core in the dash).

The coolant pipes on the Lotus are the exact same size.

Perhaps larger coolant pipes and hoses from the engine to the front of your car will help with the flow restrictions, even if it necks up/down at the engine and at the radiator. If I recall correctly, in my fuild dynamics class, a smaller pipe has more interior surface area relative to the amount of liquid flowing, so long skinny pipes create a lot more drag than larger long pipes that end up necking down and up at the ends.

The problem I have is that the coolant pipes run through the center of the chassis (steel back bone) so there is no way I can get larger diameter pipes in. I don't think is is an ultimate flow restriction as I only need to up the revs to 1500 and the flow rate is enough to cool everything down again.

suggestion: go with an electric "helper pump" for the main lines going from the engine to radiator. I bet that will solve your problems (and you will be able to get rid of that small electric pump to supply your heater core).

Something like this (pic link goes to summit racing catalog page):

Ooooooooooooooooh, I like the look of that pump much more than the Craig Davies units you see in the UK as it probably won't reduce high level flow when the mechanical pump is doing a good job when the revs are high, I'll have to see if I can find a supplier here.

The problem with the electric pump is that it can only go in the radiator feed/return pipe which is closed off when the engine is cold by the thermostat.
This would mean that the interior heater won't get any benefit until the stat opens so I'll still need the small pump for the heater.

Hence I want to find a solution which avoids the electric pump.

Hilly

 

[cbulen]

maybe your thermostat is malfunctioning, or maybe you need a lower temperature thermostat

 

[the_natrix]

why dont you see about making a new smaller pully for the waterpump...

find out the ratio of the pullies now, and then find the one to give you that extra 700-800 rpm at idle for the waterpump... should be a total no brainer for a lathe master like you!