Turbo Elise

[drb5]

What you wanting at the end of the day? Power-wise etc?


Any turbo can of course be made to fit, so you needn't go for some brand spanking new Garret jobby and if your getting some pucker liners in there, a good whack of boost shouldn't be a problem. If everything is built properly and something breaks then imo it's down to the mapping.

But you'll already know that i'm sure....i'm just gabbin away as i'm very interested.

[Mikie711]

As a foot note this is the guy that got me thinking about turbo rather than supercharger. Jump to page 9 and watch the video. You'll get the idea.

http://forums.seloc.org/viewthread.php? ... 610&page=9

I apologies about the Seloc cross post but worth watching non the less, even tough he destroys his gearbox. 380bhp what do you expect

[Mikie711]

I would be happy with anything north of 250-275. More than that and the engine would more than likely implode. I agree might have to have a rethink on the liners and get a set of banded QED ones as well as different pistons, but now is the time to decide before using the ones I have.

[drb5]

Makes for an interesting car for sure (shame we don't get the same "sticky-tyre weather" as they get) , but gearboxes are the PITA of tuning.

Soooooo much money and it's the thing you don't get a lot of choice out of. A top quality clutch certainly helps matters and i'll always try to tempt the modder into a twin/triple plate item. Takes so much more abuse/harshness off the transmission.

What makes you think the Omega's aren't good enough?


IMO try and find out where the stage after costs that much more IYSWIM. There's always a jump where costs prohibit the next mods. After then, the gain's are usually not worth all the work/cost. I'm new to this gear, so again i'm just talking.

[Mikie711]

The gearbox I have should (read hope ) be strong enough. Steel caged bearings all new, LSD etc. Clutch will probably have to be twin or triple if it gets anywhere near what I think it will. Omega don't, AFAIAA, do low compression pistons for the K series. If they do the I would be more than happy to use them. Mine are forged items with normal compression which would lead to detonation problems due to too high a compression ratio or the need to run 115 octane fuel !!.
Absolutely no idea what the next stage would be. Would be able to start with lower boost numbers and raise the bar so to speak once the bugs are ironed out.

[drb5]

Lol at the fuel.

It sounds like you have it all well planned out as it is ATM. Cost doesn't seem to be an issue either.

Only thing i think i could add, is if you go a bigger turbo than you first consider, it will run cooler and put less stress on other parts, while running less boost albeit with a bit more lag, but same hp.

[Mikie711]

That is very true. It looks like the garret GT25 is favorite at the moment and it comes in about 6 different flavors from 290 to 550 . Will probably end up talking to somebody who knows more bout them before deciding which to use. Then again I might say F%ck it and build the engine the way I was before having delusions of grandeur.

[drb5]

Nothing to say you need to buy a brand new 1k+ turbo.

There are plenty of decent units out there that'll do 300+hp that only need different flanges for your setup.

Find yourself a nice twinscroll and forget about lag.

[hiscot]

mike there are quite a few turbo k fitted into mini,s and mg zr ect with good results but i think for any serious power you will be looking at shorter rods to lower the c/r QED used to sell them ? along with the banded linners there are special manifolds around that mount the turbo very close to the block
however the turbo converted elise road test i once read stated it did not suit the elise at all
of course the box ratios will also have to be chosen to suit and i doubt yours will , quaife do a nifty gear calculator you can down load but its only rpm related with good torque a wide box should suit better and with a lower rpm a diferant diff will be required
your head would suit larger ex valves pref coated for a turbo
there is a thread on one of the sites with a build diary for a closed deck ( schollar ) turbo build with lots of photos makes intresting reading although it aint finished yet and i dont like the closed deck option but fear it may be the only way for a high power turbo k
the super charger idea imo is a better option and i have seen good r/r print outs and reports with excellent reliabilty i got offered a class winning 1.9 tt sprint engine package not so long ago but it was far from cheap
for sprinting imo a proven reliable package is the way to go

[robin]

Bernard Scouse/Autoteknix don't charge that much to slap in the Audi turbo engine and gearbox that will take you to the 300BHP mark IIRC. By the time you've engineered your bespoke solution I wonder how far away in terms of cost, power, reliability and weight you'll be from their (slightly heavyweight) solution. Though you will have the fun of having done it.

On the compression ratio, I assume you only need an extra 50% or so volume in the chamber to make the compression ratio workable for <1bar boost. You can probably lose that from the cylinder head and piston crown, plus fit the raceline gasket which is a bit thicker (couple of extra CC) plus has better fire rings I think more likely to withstand the increased cylinder pressure. You could perhaps also fit the 1.6 rods?

I don't think I would head down this track lightly ... the block is probably not stiff enough and although it won't break, I wonder if it will not instead flex enough to break the seal between the block/liner and/or liner/gasket/head ... the scholar solid deck approach probably helps in some respects, but the forces at work are quite complex, and simply bracing the block might not really fix the problem, rather just shunt it somewhere else. By the time the block is strong enough, how much lighter than the Audi is it?

Cheers,
Robin

[Mikie711]

Hiscot, thanks for the comments and yes I agree that the supercharger route would be much easier as it has been done by many before. But there in lies the problem, I want to try something different and I like the kind of power delivery you get with a turbo. Will check out the rover/MG forums and see what comes up. Thanks for that .

Robin, funny that I had just type a response talking about using 1.6 rods but you beat me to it, either great minds or fools . Might be the way to go, but I know that there are low comp pistons out there for exactly this application and together with thicker, stronger gasket would probably drop the CR enough. Was planning on using the total seal gasket, together with their top rings but will check out the raceline gasket. The valve train especially the exhaust valve does however pose an altogether different problem. Don't suppose anybody has a set of sodium filled valves for a VVC head lying around!!.
On the subject of stresses in the engine I did read on article that said turbo charging is kinder to the engine than tuning the t!ts out of it due to a turbo engine producing it's power with less revs. To do with the force required to stop the piston moving upwards at TDC, which apparently is where a lot of the stresses are generated, and I would assume at BTC as well.Hence ARP bolts etc. Don't know if this info is wholly correct but certainly made sense when I read it.
I would love to drop an Audi in but means I would end up in the same class as sports libre cars and as good as the Audi engine is I don't think it would stand a chance. So need to keep the original block which kinda limits my options. Like I said earlier would like to try something a bit different, even if it ends up been a smaller turbo with less than expected boost pressures just to limit lag and spin up times.
There is just so much I don't know at the moment, like weather the throttle bodies will take the pressure, how everything interacts ie dump valve or bleed valves, fueling, LAG, exhaust length, etc,etc, etc. If nothing else by the time I have done the research I will be a bit wiser about what is and indeed isn't possible.

Thanks everybody for your input, certainly given me plenty to think about.

Mike

[robin]

Hi Mike,

The TB's should be fine for the pressure - they're already pressure tight at ~1bar (inside is a very good vacuum on the idle) - you're reversing the direction of pressure to atmospheric, but I would think that the pressure differential would still be <1bar.

Of course you don't actually need TBs if you're turbo charging it, so perhaps using a VVC plenum will make the plumbing a bit easier.

The piston itself experiences stresses relative to their mass and RPM (hence the need for stronger & lighter pistons in higher revving engines) - the higher the RPM, the shorter the dwell time at TDC/BDC, hence the more force is required to reverse the direction of piston travel.

However, assuming your crank set is properly balanced, the forces on the block come as much from the torque - this is worse in a turbo engine (more torque) - my understanding is that this is caused by the fact that only one piston pushes at a time, while it's peer in the other bank is running the compression stroke - this causes a reaction that attempts to twist the block, as I see it (similar to the way that if you use a really long extension to undo a bolt, in addition to the torque applied to the bolt, there is another force at 90 degrees to the axis of the extension bar).

You'll need an oil cooler!!

Cheers,
Robin

[Rich H]

I think the lag would be significant but not too bad. You really should drop P.A.T on Norlog a line, while its a T series he has come formt he world of 200SXs and knows alot about ropey Turbo installs. His setup is very tidy now.

The hosepipe thing was not quite accurate, what they meant to say was a small bore exhaust will maintian gas speed (Therefore most of the temperature) to the turbo, so it can be moved further back, also you aren't on about putting it at the back of a front engined car, just a little further form the exhaust. The valves would like it better too.

[hiscot]

mike i have looked into turbo k myself and imo its a non runner as robin has said the block aint stiff enough thats why rover stuck with 160 bhp on their turbo k but if your going ahead anyway the rover t block is the best starting point it has been stiffened with lower c/r but still not low enough for any decent power you can get upto 190/200 from this engine with a remap
the 1.4 closed deck looks to be the best choice and 250 bhp is acheivable
i think the turbo k also has a sealed t bod for forced induction but i doubt your t bods will cope besides with forced induction a single t bod works fine
the tt230 used a carefully rebuilt block with differant rods / pistons to lower the c/r this would suit you better
the tt260 was masively rebuilt and strenghened as where the turbo k series of the day costing 12k + 6-7 yrs ago
the twin plate clutch i have also looked into mainly for lightness and full throttle gearshift however for road use its a no/no the best setup i found was from japan as it came with a matching flywheel and good torque handling expect to pay 1k
you can get a custom single plate although reported as heavy but its up to the job an nicer to the drive chain and town use
for my tuned k i use a rover spec clutch thats built to take more bhp and torque than a k series
as for the audi option i believe you can feel the differance with the weight however a good road test would tell if it suits the car or you i think there maybe another player doing installs soon theres even a diesil version being fitted into an elise

[Mikie711]

The more I look at the more it becomes apparent that the biggest problem is block strength. Closed deck, Lexus liners, steel sandwich plate would solve that problem but that makes it Very Very expensive . The remainder of the engine internals I already have in upgraded form, will have to look at what is available and take it from there.
Turns out the turbo and plumbing is the easy bit, even getting it to fit where it should go is possible. There is enough room between the bottom of the forward face of the engine block and the bulkhead in the elise, just, but boy would it make for a warm cabin as there wouldn't be room for any heat shielding.
You are right the DHTB's would go and it would be a plenum with single TB probably from the rover 75 or ZT as both of these ran the low pressure 1.8T setup. Would like to get a look at one but seems they where never a big seller, be handy to trip over one at a scrappy's but may be a bit new for that yet.
Had a look on the rover forums and this has indeed been done a few times but most of the threads have no close out on them so difficult to tell weather it was a success, one build went with the Evo 4 block from scholar to retain the original displacement with a GT28 turbo, steel rode low comp pistons and planning to run over 1 bar of boost which would be spot on if it worked.

Investigations continue................................

As a footnote I did find 1 company that does this conversionhttp://www.morego.co.uk/bbr-gti/RoverK300T.php. Turbotechnics only ever did one and they recon it cost £40,000 for the engine and £150,000 for the whole car

Mike