Triumph GT6

Honestly, if you put the TR6 2.5 block in the GT6, you'll be making more power than the GT6 chassis really knows what to do with.

There are supercharger kits, too.

I don't get me wrong I know it is possible to make some power but its not the way I envision it. I was really hoping to turbocharge it. After talking with more experienced people then me, turbocharging that motor wasn't going to work. I was looking for 200-300hp to the wheels. I wanted a beast of a car. Even with the car being as light as it is a 150hp just isn't enough for track use for me (VIR, I would get killed in the straights).

It might sound dumb/ridiculous and I that I am not making any compromises but what I want doesn't sound possible without having a huge piggy bank.

It some point in time I will own a GT 6. It might not be for track use but I love the way that little car looks.

Get an MGB-GT. You can take your pick of 4, 6 and 8 cylinder engines that will fit pretty well, it's almost as light as the GT6, and it's a much tougher, more robust car than the GT-6.

They just dont look as good to me.

Maybe, but they're good looking little cars in their own right, and a way better base for what you're thinking.

I drove my 70 GT6 into work today and I was grinning from ear to ear. The car doesn't need 300HP to have fun in. I have a stock motor, headers and a lowered front end and the little car just sticks and goes. I can take 20 MPH corners at 40, for day to day driving, how much fun is that? I have a Spitfire Race car and this car is almost as fun but I can drive every day if I want to.

There's one on eBay (Item number: 170332783579) right now for $1500. Where can you get a classic looking car that's this much fun for under $2K?

mike

My GT6

It does look nice. But 95-112hp just isnt going to cut on the race track when you have 500hp vettes and 911 with you.

Yeah, I know what you mean. I loved my 1970 GT6+ too but like you I didn't fool myself about its stock capabilities.

Don't discount the turboed 4 banger thing. Miatas can make 300 boosted HP pretty easily with a decent life expectancy. Put that in a ~1800 pound car and there's lots of entertainment to be had.

I agree with Jensenman. I have a Spit 6 conversion (MkI GT6 engine in a 78 Spitfire body/chassis). It's a fun car, but it has it's limitations under severe use. Like you, I've had occasional delusions about improving performance. The trans isn't too much of an issue - T9 swaps are available... but the rear diff... that is a deal-killer... or at least a forward-motion-wallet-killer.

In all honesty, I've contemplated building a nicely balanced 1500 engine and converting the car back to a Spitfire to regain the Spit's better weight distribution... rather than going through the hassle of copying Paul Tegler's FIS6 (a Spit 6 w/ the engine set back into the I-4's position by chopping out the firewall and reworking the frame a bit). I ran the auto-x at Carlisle and even with uprated springs and shocks, the car understeers like nothing I've ever driven when pushed hard (and I normally drive a VW MkIV)...

Fitting a different engine into a Spit/GT6 chassis is fraught with issues... mostly revolving around space and the lack of it... the 2.0L 6 barely fits in the car as-is... and while converting it to a 2.5L is possible for some blocks (crank swap for Mk2 and MK3 engines) you are still left with trans and diff constraints... and the 2.0 is generally considered a better rev'er...

There was a GM V6 conversion at Carlisle this past w/e for sale... the guy built it as a race car... under what specs? Who the hell knows... but he butchered the frame to make room for the exhaust... and while it did have some nice (and pricey) PRI parts on it, the car was too scary to consider. Especially for the price (wanted around $15K... does that come with the crack he's smoking?)

Or I'll just buy another car for track-duty and enjoy the Spit for what it is: a fun little back-roads cruiser... especially after installing a decent stereo...

FWIW, I talked to the guy who builds the RATCo TR6 frames... he's looking at producing Spit frames... my comment to him is that reproducing stock frames would be kinda pointless - there are still many to be found in useable condition... but a more performace oriented frame, however... one already set-up for say a Miata rear diff and suspension... maybe motor, trans and front suspension as well... could possibly have a market...

well, can you build a "locost" frame to fit under the spit/6 to take the miata's drivetrain?

Sure. In fact it's been done more than a couple of times. There's a guy who used to occasionally post on the old forum who had a '79 Spitfire with a RX7 TII rotary and 2nd gen suspension under it. That one had a complete space frame which he set the Spitfire body shell onto. Nice work, nice looking car. There's a couple of videos of it on YouTube, search for 'turbo rotary spitfire'.

I think I need to point out that if someone is considering going that direction, you'll need to have a cage. A simple ladder frame would allow the GT6 doors to be used but that kind of frame would flex like it's made of chewing gum. A Locost type frame with all the side tubes would make the car nearly impossible to get in or out of, this wouldn't be so bad with a Spitfire with the top down. There's not really enough space for a backbone frame (hell, even Miata seats are a TIGHT fit in the standard car) and the body shell does not add any real rigidity.

I'm seeing a theme here: Take a GT6, remove the body, engine, frame, transmission, rear end, suspension, wheels, tires, anything left except the gas cap, build a complete car from scratch using Japanese components for the major parts, replicate the body parts in fiberglass (the originals rusted away anyway), put the gas cap back on. Yeah, I think that's do-able. However, at that point, it will probably still blow transmissions and rear ends because you couldn't exercise the spirit from the gas cap.

Dummy. That's why you use a Jap fuel cap. Sheesh. I would think anyone who wns not one but 2 Loti would know THAT.

not sure how much of what I'm about to say will end up coming out of my ass and how much out of my mouth, but would a Fox Body Mustang 4 banger fit? that would get you the 5th gear, and they could be had from the factory with a turbo, although I'm not sure if the '83 and later Turbo GT cars suffered from the same engine issues as the earlier 2.3L Turbo lump did. as for the diff, Ford Thunderbird diff, or perhaps a Speedway Engineering Stock Car Mini quick change IRS setup? if you were in for a bit of suspension engineering at the same time, neither option would be too particularly hard to do. and then of course you've got the Miata engine options, rotary conversions, small BMW engine swaps, possibly a chevy 4 banger swap, and any number of inline 4 or 6 small engines other than what I've mentioned

DISCLAIMER: some or all of the above post may be complete and total BS, as I am not familiar with the GT6 or the fox body mustang, or the size of many/any of Ford's 4 bangers

The turbo 2.3 has been done successfully, dherr's '06 Challenge car is but one example. Had it been me, I would have moved the lump further back and down. I did a 2.0 German Ford in a 1968 Spit, it worked out well except for the fragile diff. That car would easily beat a first gen RX7 in the acceleration and braking department.

I drove a GT6 (MKII with an updated rear suspension, I think) across Ontario one winter. Middle of December, we had the windows open and heater off. Anyhow, when I delivered it to the new owner I said "feels like the front shocks are worn out and it's sitting on the rear bumpstops". Local LBC shop gave the car the once-over and said "nope, it's perfect"

They do look cool though. Especially that great hood opening.

I have a GT6+ 'laying around'. Based on a Duratec Spitfire conversion that's being done (Loren's), I think that you could swap in the Duratec based 2001+ Ranger 2.3 DOHC & 5 speed without too much hassle. The oil pan hump is in the right place. The motor fits under the hood, and between the suspension towers. The exhaust is on the passenger side, so no custom header is required to clear the steering. It's a whole package set up for RWD, so no messing with bellhousings, clutch slave cylinders, etc. The motor & trans is certainly going to be lighter than the stock 6 & trans. It's a modern, supported motor with around 140 HP stock, but plenty of go-fast parts if you want. Can find one with low miles, no rebuild needed. Might need to roll a custom intake manifold, but a short, direct IR or plenum configuration is easy. Injectors are mounted in the head, so that makes the manifold and plumbing easier. Moves the CG back without major surgery, restoring the balance and nimbleness to Spitfire-like levels.. For the rear, either the ex-Merkur diff (Sierra), or an aluminum cased T-Bird/MkVIII/Mustang IRS (keeps the whole driveline Ford). Use coilovers instead of the transverse leaf, and fab some upper links to take it's place, an opportunity to address the GT6+ rear geometry shortcomings. Or adapt the rear uprights from some other candidate to get disk brakes.

Carter

erohslc wrote: For the rear, either the ex-Merkur diff (Sierra), or an aluminum cased T-Bird/MkVIII/Mustang IRS (keeps the whole driveline Ford). Use coilovers instead of the transverse leaf, and fab some upper links to take it's place, an opportunity to address the GT6+ rear geometry shortcomings. Or adapt the rear uprights from some other candidate to get disk brakes. Carter

I've had similar thoughts... but again, the issue becomes a matter of space and how much chopping, welding and frame modifications you're willing to make... body adjsutments may be required as well.

I was able to get a second gen RX7 diff and Miata uprights under my '80 Spit body with fairly minimal body and frame modifications. I had to add to, not cut away from, the frame to mount the upper control arms which are cut down Miata parts. I got 13x8 wheels with 5" backspacing under it by just banging the inside fender lip flat.

Jensenman wrote: I was able to get a second gen RX7 diff and Miata uprights under my '80 Spit body with fairly minimal body and frame modifications. I had to add to, not cut away from, the frame to mount the upper control arms which are cut down Miata parts. I got 13x8 wheels with 5" backspacing under it by just banging the inside fender lip flat.

Pics?

The green tubing is what I added to create a top mount point for the upper control arm. I figured the length of the lower control arm, then multiplied that by .70 to come up with the upper control arm length, and that measurement determined where to put the upper inner mount. The .70 figure is because that is the percentage which gives the most reasonable camber curve. I figured the lower C/A length by: measuring the inside of the body from the outer fender to outer fender (used the inside lip as my measurement point), subtracting 1/2" to allow 1/4" tire clearance for each side, then subtracting the wheel front spacing measurement (have to double this measurement) then subtracting the distance from the rotor face to the center of the lower outer pivot on the upright (again have to double this measurement) then subtract the width of the frame plus the inner mount measurement from mount face to bolt center (again doubled). I have it written down somewhere, but IIRC the final measurement was something like 11 1/4". That was the center to center measurement for the pivot eyes on the lower C/A. The upper C/A center to center was then .70 of that.

You can see the shortened Miata upper control arms in this shot, along with the home fabricated lower control arms. The lower inner mounts are Spitfire front lower control arm mounts. The front mounting already had an internal reinforcement inside the frame where I drilled the hole, the rear mount had to have a piece of tubing put through the frame and a piece of 1/4" steel welded to the inside where the nut tightens down so the frame tube wouldn't get crushed when torquing it down. I considered welding the mounts to the frame but that would mean toe adjustment wouldn't be possible. One thing I would change, knowing what I know now: lower the upper shock mount about 3/4" so the control arms could have more drop. Those are Yamaha R1 shocks, BTW. The front diff mount is a 2nd gen RX7 piece with the 'arm' cut off.

A Miata diff would be an easy fit as well.

Either way, you have to cut the original mount ears off of the diff. I tried everything I could think of; there's just no way to use the original mount ears without completely butchering the rear of the frame and the bottom of the body.

The diff mount is a piece of 1/4 " plate with two pieces of tubing welded through holes in the back. Those tubes have further tubes attached at 90 degrees, those have rubber bushings inside so the diff can flex on the mountings. The three large nuts on top are on studs threaded into the top of the diff case, they are offset so they'll be in the thickest part of the case. The small bolts on top bolt to another piece which is mounted to the rear of the diff case, you can see one of the 4 Allen head bolts which attach this piece to the case.

All this fits under a Spitfire body with minimal hammering. A GT6 has a somewhat different rear stamping, it might actually be easier. I would not recommend trying to build this with the body in place.

Very nice work sir! I really like those shocks. What kind of motor/trans do I see lurking at the front part of the chassis?

Here's one way to get semi-bolt in fitment for a R180 diff from EnZed:

http://homepages.paradise.net.nz/lghrnrm/tessapg2.htm

The Sierra diff I have is quite compact, the Ford T-Bird/Mark VIII/Mustang GT somewhat less so, but still do-able.

The stock GT6+ lower wishbones are cast from 'the heaviest metal known to man' to quote to one of our fellow listers. But going with CV axles eliminates the need to route them around the rotoflex dounts, and so they can be replaced with lightweight units built from straight steel tubing that bolt up to the stock mounts. You can replace the transverse leaf spring with upper links, but they can't be simple heim joint links because they must take the same fore/aft loads from the top of the upright as the blades of the leaf spring. There's very little room to put anything like a trailing/leading link up there, it would be so short that the dive/squat geometry would suck badly. A narrow wishbone would do the trick. Luckily, the forces at the top are a lot less than at the bottom, note the straightforward Miata upper control arms that depend on the stiffness of the bushings to do the job.

Carter

Thanks for the kind words! That rear suspension took a LOT of head scratching, measuring and cussing. BTW, the front 'legs' of the upper C/A mount pretty much have to be in that spot for the reason you mentioned: the lower arm has to be a fairly wide triangle to compensate for the braking twist force that's fed into it. The rear leg is straight, the front leg is angled 20 degrees. The upper arm could have been custom fabbed as well, but the 'curve' of the modifed Miata C/A allowed more clearance between the arm and the body at full bump. Might as well take advantage of their engineering.

The lower shock mount needs to be as close as possible to the outside end of the C/A so that a reasonable wheel spring rate can be achieved without going to stupid high rate springs. Even 1/2" further in makes a HUGE difference in wheel rate. To help make it simpler, I mounted the front and rear shocks at the same angle of 25 degrees. When I got it all together, it took a 450 inch pound spring to get a ~200 pound wheel rate.

That is a Mazda 12A rotary perched up there for one of MANY test fits.

In reply to Jensenman:

Just found this forum. Great to see so many GT6 lovers. I woke up this morning and realized, 'Man, I miss that car', as many of us do. I was searching for info on the factory performance parts that Triumph offered in the '70s. I had a '69 GT6 MKII. The first car I ever bought on credit. My Dad had to cosign the note at the bank, but off I went in my hot red coupe. After driving a Sunbeam Alpine for a while, I was ready for SIX cylinders. Yup. Then I found a manual on upgrading the performance of the little six motor and ordered triple valve springs, camshaft, long tube headers from Triumph while I pulled the head and ported and polished it. There seemed to be a lot of meat to clean up the flow, and I had it milled slightly to raise the compression. After all was done, I had this one friend with an Alfa who just wouldn't quit trying to follow me in a game of 'Cat and Mouse'. I so agree with JensenMan. The cars were beautiful as works of manufacturing art, and changing motors or doing anything other than a few 'factory' mods is unholy. These cars were made with the art of engineering as their driving design force. Would be nice to see a set of wires of that BRG beauty, tho'.

Anyone know of, or ever heard of, these rare factory parts? I traded the car to guy in LA who owned a custom hardtail chopper Triumph Bonneville. Wish I could find that. The factory manual suggested that 200 hp was possible with these mods and still be streetable. Was plenty for me!