1999 Ultima Spyder
Discussion
A bit of background
I built this Spyder back in 1997 with a Renault 25 V6 Turbo motor & UN1 Gearbox.
It was good and I was a fairly early adopter of building a kit car with an EFI motor, especially turboed.
It always ran well - but time passes and I decided a few years back to re-engine it.
I bought an engine, gearbox, custom flywheel & clutch for it - and then parked it for another few years...
Getting Started
Roll on 2021 and I decided I really must make a start on actually doing this conversion.
So I now had:
- an AHC Audi V8 Motor
- and a GVC 01X G-speed Box
Time to take the old engine out:
Almost twice the horsepower, but hardly any bigger:
Chassis Modifications.
Still learning the new welder, but seemed to go OK:
Engine looks like it was made to fit, good clearance all round on the chassis and body - which is excellent, I don't think anyone has tried to squeeze one of these motors in to a spyder before, they have less hood clearance than the sports/gtr/can-am.
Sump protudes about 15mm out the bottom - which is a less than the old motor did and also shed loads less than a SBC would.
The motor was sitting on wooden blocks in the new chassis in this pic while we check clearances:
Next step, steel on order to make the engine mounts next, just waiting on order to arrive and will wheel out the welder again, while I ponder gear linkages as well.
Gear linkage was a proper chin scratcher to try and K.I.S.S, but I had a plan.
Chassis mods were completed along with engine & gearbox mounts.
Christmas 2023 - Gear Linkage
With a far too long hiatus, I spent some time over christmas doing the gear linkage. It's just mocked up for now (hence jubilee clips and over-length rods), but works really well and all gears fit in the perfectly.
The gearbox end - the "lever" that makes it all happen. Will be shortened eventually:
Detail of the shifter bar. I reused as much as I could of the old UN1 linkage mechanism - although the audi box shifts the other way round entirely:
But it seems to work. I cut the old gate around a bit just to see if it would all work, will probably get a nice laser cut one eventually:
Driveshafts
Then the CV Joints arrived so I spent a bit of time mocking up the first driveshaft with some 25mm tube.
When designing the engine & gearbox mounts, I spent a lot of time making sure the engine was as far forward and as low down as I could make it, which you can see from the driveshaft angles.
There's at least 19mm of possible movement (at full drop) on the driveshaft, and 23mm movement resting height, and 22mm on the bump stops. So nothing bottoms out.
As of Feb 24, I'm waiting for the driveshafts to arrive.
Alternator mounts.
I tried quite hard to mount the alternator on the OS of the car, modifying the original mount. But I've actually mounted the engine so low in the chassis that the alternator fouled.
Obviously some of what I am doing is inspired by "Hilly's" Lotus that you can find on motorgeek - esp using the 01x and Audi V8 motors together - and in this case, had to switch the alternator to a NS mount like his.
However. my engine mounts are completely different to his - and therefore so is my alternator mount which is a standalone unit. Even considered using a different (smaller) alternator, but couldn't easily find one that I could be sure would be easier to fit, and I had this one on the shelf already/
I also did away with the automatic tensioner design and have just gone with manual adjustment for the sake of simpler fabrication (this version version 3 already - V1 was modifying the original, then I made a V2 to trial the OS fitment and worked out all the measurements to get it spot on - and then based on lessons from that I did V3!). But I think it all came out OK and if I have to adjust the belt tension every couple of years - no big deal!
OS one that didn't quite work:
You can just about see the bottom mount here. Forgot to take a decent pic of it on it's own.
Top bracket and adjuster. Will clean it all up and powdercoat eventually.
It is pretty much perfectly aligned.
Exhausts
Exhausts next. I temporarily put the bodywork back on to check everything will fit OK since the spyder has the lowest of rear clam of all the models:
I tried to do something in CAD
But quickly hit the limitations of 2D CAD, so just decided to have a go and crack on.
I've always viewed making headers as "dark magic", it's a tight fit to clear the chassis.
Am happy enough with the first three pipes, but the 4th was not so good:
I redid the final one on this side, I think it's come out much better and tweaked the geometry of cylinder 3 to give a bit more clearance and level out the collector (not shown in this pic)
ECU
I have the ECU already. I've done a couple of megasquirts before (that I built myself), but this time while I've still gone megasquirt, I like the look of the prebuilt MS3. One the one hand, I'm being a bit pre-emptive, but on the other, it lets me think about "packaging".
Tie Bar
Also made the engine tie bar:
That's progress so far. Next I need to start the offside header, I think I have enough bits in stock, before I can start thinking about the rest of the exhaust system then.
Edited by Arnold Cunningham on Tuesday 20th February 22:50
Yeah - they've always been a mystery. I spent ages looking at the different styles & layouts. I have the cylinder -> collector layout as intended, basically it's the only way I could get it to clear the chassis. But everything else has just been cut and tweaked to fit. Always the same, by the time you finish the job you know enough about it such that next time you could do a better job of it, but then never need to.
Yeah, the Renault engine was good - but also a bit wheezy. I had just bought a new turbo for it and was going to up the boost a bit to give me a bit more go - but the exhaust was then going to become a limitation where I'd just be adding more heat, rather than power. The old UN1 gearbox it was coupled to was also OK. Although, the gear ratios might have been OK for a Renault 25, I always found they were poor for this.
For example, to do a quick launch, I needed to use first so I could get the car rolling enough to get the revs into a place where it would generate boost - albeit it hit the redline in first quickly enough that it didn't actually come on boost. And starting in 2nd needed far to much clutch slipping to get it on boost, so that wasn't ideal either. So 33mph @ redline in first.
Then into 2nd, which pulled well enough - but redlined at 54mph. So to get to 60, I'd need to then change into 3rd!
With the new gearbox, Audi made so many variations of the 01X in different ratios that I think I should be seeing 37 in first, but more importantly, 65 in 2nd. So I hope in terms of driveability, this should be a much better setup - much more torque and a better gear ratio set too. And it's a close ratio box, so hopefully I've chosen the one that should just about redline in 6th, too.
Anyway, the B295 Renault engine & box were snapped up by a guy who restores the old Renault Alpines.
For example, to do a quick launch, I needed to use first so I could get the car rolling enough to get the revs into a place where it would generate boost - albeit it hit the redline in first quickly enough that it didn't actually come on boost. And starting in 2nd needed far to much clutch slipping to get it on boost, so that wasn't ideal either. So 33mph @ redline in first.
Then into 2nd, which pulled well enough - but redlined at 54mph. So to get to 60, I'd need to then change into 3rd!
With the new gearbox, Audi made so many variations of the 01X in different ratios that I think I should be seeing 37 in first, but more importantly, 65 in 2nd. So I hope in terms of driveability, this should be a much better setup - much more torque and a better gear ratio set too. And it's a close ratio box, so hopefully I've chosen the one that should just about redline in 6th, too.
Anyway, the B295 Renault engine & box were snapped up by a guy who restores the old Renault Alpines.
gobs
te said:
te said: Loved the spider since I saw one in kit car magazine, dark red.
That was most likely P412 DNN - the factory demonstrator at the time. It was actually an earlier blue one in the advert in "which kit" which made me want to buy one. I was a student at the time and myself and a buddy used to get a copy of which kit from his mum (she worked for them) each month.
MustangGT said:
Ultimas have always intrigued me, I prefer the hardtop version personally.
Most people seem to put in Chevy engines though, many parts available for these, though I do like the Audi motor.
I've got a 700hp Chevy that I built in my boat. I fancied doing something a little different here.Most people seem to put in Chevy engines though, many parts available for these, though I do like the Audi motor.
I like the Audi motor, I have one in my old C5 RS6 that I've done lots of work on - plus I liked how light it all is, how compact it is (the spyder has the least amount of space under the rear body), not having to run the gearbox upside down (Porsche boxes), no adaptor plates and well matched, 6-speed, close gear ratios.
Made some progress today on the other side:
Edited by Arnold Cunningham on Wednesday 21st February 19:38
2nd header is pretty much done. It took a few goes to get it about right, since I didn't just need it to fit, I need it to be the same as the first one.
I'll equal up the primary lengths L to R a bit, but am currently waiting on some 2.5" straight tube to arrive so I can start making the rest of it. I have a set of bends and an x-pipe already - who would have thought the straight bit is the hardest to get actually delivered.
I'll equal up the primary lengths L to R a bit, but am currently waiting on some 2.5" straight tube to arrive so I can start making the rest of it. I have a set of bends and an x-pipe already - who would have thought the straight bit is the hardest to get actually delivered.
Edited by Arnold Cunningham on Thursday 29th February 22:51
josh00mac said:
Great project and really interesting to see one with an Audi V8 as opposed to the usual. I may have missed this - is the box from a donor Audi? (RS4?)
And is there a thread about your C5 RS6?
Not quite sure the exact car the box came from, but it's an Audi 01X 6 speed, close ratio, manual box. No adaptor plates needed, and if I've got my sums right, should just about be able to hit the red line in 6th, in theory.And is there a thread about your C5 RS6?
Finished the headers today, all welded up. So many lessons learnt, if I had to make another set I could do a much nicer job next time.
Nevertheless, I'm not unhappy with how they've turned out for a first go by a bloke in his garage. My tig welding has improved too - by the end of the job, I was starting to be happy with some of the welds. I'm waiting on various flanges and other bits to arrive to starting making the rest of it
Anyway, pics...
Nevertheless, I'm not unhappy with how they've turned out for a first go by a bloke in his garage. My tig welding has improved too - by the end of the job, I was starting to be happy with some of the welds. I'm waiting on various flanges and other bits to arrive to starting making the rest of it
Anyway, pics...
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