High HP TR6?

I absolutely loved my TR6, but it was shagged and was always pretty hard to handle given the fact that it was slower than a Miata in every way. I intend to buy the absolute nicest roller I can find someday with the goal of a BMW M50 swap. Goodparts has made a lot of headway in fixing the TR6's foibles with the Nissan R200 diff swap and heavily strengthened axles. The frame flexiness can be solved with POR-15, a welder, and some decent steel to box & reinforce the whole thing - that being said, it may be 'cheap' to do that but, what is your time worth? I will gladly do it with my next TR6 but I just love them that much...

Reckon Kas would know about building a six? Reckon he'll be at the Mitty?

mguar wrote:

tuna55 wrote:

mguar wrote: (and GM mid sized SUV's Trailblazer/GMC Envoy) which use a modified Jaguar in line six)

Nope. That's a GM design.

Well GM bought the engine and machine tools from Jaguar prior to Fords Purchase of Jaguar.. It's the only thing they bought after spending millions. On the other hand someone leaked to Ford the fact that Jaguar was for sale and At the last moment Ford made a too good to be rejected bid for a company that still had a lot of machine tools in use from WW2 and before.. Check the specs such as bore spacing etc.. While GM's has a 4.2 litre size compared to the 4.0 size in the case of Jaguar check other specs for confirmation.. You will note that GM uses it's own fuel injection instead of the Lucas injection but the camshafts etc are straight from Jaguar.. Is it a GM design? Well at least it's GM modified. * Note believe it or not the GM version isn't as reliable as the Jaguar version..

I can't prove a negative. Prove that it is, because that's the first I have heard of it. I am pretty sure it was a clean sheet.

mguar wrote:

JoeTR6 wrote: We've been autocrossing a TR6 for about 10 years that probably manages 150-160 HP at the wheels. It's streetable, even with triple Webers. Since it ate the cam a few years ago, we've had the opportunity to rework things a bit and add a slightly more radical cam. The sound is really pretty nice, but adding even 20 HP makes me start to worry about breaking the crank, a U-joint, etc. Once it's broken in, it's getting dyno'ed before going back to any autocross. The real limitation is the crankshaft and bearing design. The crank has bad harmonics above 6200 RPM or so that can break the crank or shake the flywheel loose. A forged crank with extra flywheel bolts and proper balance is the fix, but not for cheap. Then there's the con rods and pistons to worry about. And the inadequate main bearings and thrust washers. As others have said, it's not the best high-power engine out there, but puts out decent torque and can be made to rev with a lightened flywheel. I'd highly recommend an ignition with a rev limiter to keep the RPMs below 6200 on stock internal s. BTW, we have the TWM/Borla intake shown above. It's the only one in existence at the moment. Once we get the engine bedded in with the Webers, we're going Megasquirt and fully sequential EFI. After that, I'll probably have a better idea what the upper limit is.

Based on Jaguar V12's with megasquirt don't expect anything other than a trivial gain in power but much easier adjustability.. Compared to Webers on a V12 Jaguar.. That's almost impossible to document because few Weber carbs are properly developed and since there is so much tune-ability with Webers it's almost never fully developed where as with a mega squirt adjustability doesn't require $600 worth of jets chokes and etc.. each time. In fact The most Powerful V12 on record is still running with Webers..

In the 907 Lotus world, hands down the single biggest improvement is direct ignition. Electromotive makes a stand alone module (Tec 3) with easily adjustable advance curve points that really wake the engine up. The stock engine was rated at 144 HP at 5800 RPM, with the Tec 3 170 HP with Dellortos is not unusual. There's a Megasquirt/Tec 3 engine with stock bore/stroke/cams over in England which touched 198 HP on the dyno. Add the 107 cams and a 2.2 stroker crank, you'll see 225 HP easily.

FI removes the jetting changes from the equation. That means the real benefit of MS etc is the ability to go with crank trigger ignition which allows '3D' ignition mapping. That's what allowed Yamaha to make 44HP at 9800 RPM with an 11,500 RPM redline from 398cc with a flat slide carburetor.

And put a warranty on it.

mguar wrote: Based on Jaguar V12's with megasquirt don't expect anything other than a trivial gain in power but much easier adjustability.. Compared to Webers on a V12 Jaguar.. That's almost impossible to document because few Weber carbs are properly developed and since there is so much tune-ability with Webers it's almost never fully developed where as with a mega squirt adjustability doesn't require $600 worth of jets chokes and etc.. each time. In fact The most Powerful V12 on record is still running with Webers..

Understood. We're mainly switching to EFI for tunability and better throttle control. Webers are great carbs, but as you mentioned, difficult to achieve a proper tune for all conditions. We're still fiddling with the accelerator jets.

BTW, we already use an Electromotive HPV-1 ignition. I'm going to try using Megasquirt for ignition, but the Electromotive unit is quite good for being an older design.

Hmmm. GM did own Lotus for a while, the 9xx series cylinder heads were the basis for the Caddy Northstar heads. One of the Jensen Healey Preservation Society members was a GM engineer, he bought the two 912 engines (the short blocks) that GM robbed the heads from for the first Northstar development mule. One of those is in his personal J-H but has a 907 head. And of course Lotus originally used a Vauxhall (British GM) 2.3 engine as the development mule for the design of the 9xx series heads, so I guess it all came full circle.

In reply to Curmudgeon:

In your Tec3 example, I would need the stock FI system from a European TR6 plus the Tec3 correct? Pleas excuse my ignorance, trying to learn all of this...

The Tec 3 is about $3000. Does that sound right? That with a stock rebuild and a mild cam would put me in the neighborhood?