Engine choice again.

[snurdf]

I was just searching some old threads trying to get some info on the Delta turbo situation & I came across a 6 pager about engine choice started by aomeone who wanted to put a cossie engine in a HF.

The general consensus seemed to be against turbos for cooling reasons mainly & I noticed that no one mentioned the mr2 turbo.

I had one of these a few years back. It was a '92 model (rev2) which means it was 220 bhp in standard form. It ended up running 260+ before it met with an accident, but the point I'm getting at is that it was happy with this output. You could thrash it all day with no cooling issues & that was with the standard intercooler.

The mr2 does have side vents which are bigger than the HF ones but it also uses cool air from under the car which exits through the louvered engine cover. there are plenty of 2's running 300bhp + daily with no issues.

It's a very strong engine in standard form & I can assure you that 260bhp in one of these is very quick so imagine what it would go like in a strat with the weight difference.

There are also quite a few boot mount intercooler versions about.

And to top it off you can pick these engines up at decent money. In fact you can buy a decent car for not so much now.

Roy.

[strat6v]

I think the stratos replica has a negative pressure zone underneath, as found by John Whalley's integrale/thema engined car. Had the same engine myself, as did the two sets of twins, one with the benneton rep and the others with the castrol rep. To get your cooling isuues sorted you would need to stick some decent size scoops on the sides or top of the rear section, can be done but does spoil the car. Turbo's are all fine and good but the lag issues you'll find aren't so the more boost you want, the worse it gets.

What i'm trying to say is some including myself went down this path, and found it aint as good as what you think. Big boost coming on tap half way round a corner would be no joke in a strat, far worse than an mr2 i converted back to a v6. reasons were sound, lag issues (if you use some form of antilag it will wreck your turbo inside a weekend) cost, spoiling the look of the car etc.

Now if you are talking supercharging then thats a whole different ball game, a few here are going low blow on v6's, 300bhp with super wide torque, no lag.......... ;)

[l3hou]

Hello John

The chap on the London to Brighton stand at Brooklands Auto Italia had a very nice Beta montecarlo with the Alfa 12v v6 plus a HUGE Aston Martin (eton) supercharger. Weeeeee - what a sound!

He's built this up himself and reckons to have a pretty solid 270hp on what he felt was a stronger bottom end 12v. He's a decent chap - I believe him as he built this himself. I know zip-all about these things, but the work is excellent and a visit to the Montecarlo forum to find Paul Millett might give some more info.

Cheers

J-P

[Bernard]

Met Paul a few times..... as you say very knowledgable and all his own work... he must have spent hours on development

B

[snurdf]

Yeah, I know what your saying John. I was just doing comparrisons in my head to the Strat & MR2 set up, they are very similar.
I was thinking with ducting from underneath to the Air filter & the intercooler and a louvered engine lid like the 2 that things would probably be similar. The 2 also has a fan on the intercooler.

[strat6v]

The car sits very close to the ground already so scoops sticking down wouldn't be very good, for an intercooler it would need to be pretty big too.
Guess you could charge cool it and run a pre rad up front. if that sounds the way to go, contact brise in kent. They have developed a very efficient core for intercoolers. Celica gt4's have a nice leccy chargecooler pump or maybe a small Davies Craig unit. efficient intercooling is the key to it all, if you can't cool the charge enough then it's not really worth bothering. You can actually end up with less power, even after winding up the boost!

Your fuel system will probably need upgrading from the usual standard set up on a strat. If you have fuel starvation problems when cornering/accelerating/braking then it could be bye bye engine :eek:

Do all the calculations you can, ie weight of a v6 strat, weight of a turbo'd setup etc. Factor in the percentage of extra weight added with all the kit then that will tell you how much power you will need to add, just to get back to a level playing field.

It would be a good idea to speak to John Whalley on the subject, i don't think the two lots of twins have the turbo cars anymore :confused:

Hope i've been of some help. Please don't think i'm being negative and trying to put you off, thats not the case. I'm hoping to have my number two chassis in the shop over winter for refabricating then the supercharged 24v will be going in the back. :)

[snurdf]

Please don't think i'm being negative and trying to put you off, thats not the case. I'm hoping to have my number two chassis in the shop over winter for refabricating then the supercharged 24v will be going in the back. :)
No not at all John, more like thanks for your views & advice. This is what the forum's for.
I'm fairly knowlegable on the basics of turbo tuning but when it comes to the Strat I'm right at the start of the learning curve. I hope people don't mind folk like myself comming on here picking their brains. Hopefully, a few years down the line I'll be helping out answering questions for the next generation of Strat builders.
I had a "Which engine?" post the other week & learned alot from it mainly about the V6s & I'm sure a few others gained something from it too. When you get loads of people coming on sticking in their two peneth you get to learn all maner off useful tips.
Cheers all. ;)

I'll look forward to following the progress on the supercharger project.

[strat6v]

Once i start, i'l post a weekly update with some pics. Just got to finish 'little eric' first :)

[Sptwoman]

Worth noting that Chris Smith is "playing" with supercharger technology I believe! A small discreet installation would be a real investment.

[Swamprat33]

Erm, I think you may be talking about Mr Chris Savage.

[strat6v]

Allens right Tim, Both Chris's are dabbling in the black art! Ssssshhh.... it's all top secret though so don't tell anybody :)

[Martin K]

We are running an Integrale/Thema type turbo engine in our race car - well we will be when we get the exhaust cam sorted! At the moment it won't rev cleanly above 4500 rpm, but the engine is already putting out 190 bhp at that speed. Well over 300 bhp is our target with the turbo we have fitted and over 400 bhp with a larger turbo later on.

The main problem with turbo engines has been mentioned here already - charge temperature. On our (race) car the air/air charge cooler (intercooler) is mounted in a pod with it's own duct on the side of the car - but the car was designed that way. With the Stratos adding an intercooler at the rear will give a problem to solve. You could do what Ford did with the RS200 and run the intercooler across the rear of the roof, but it won't enhance the appearance of your Stratos. If you want the intercooler at the rear, then I think the only proper way to know where to place it is to get in a wind tunnel. Other rear engined cars have been turbo'd and used rear monted intercoolers with success - Porsches being a prime example.

At first glance using an air/water charge cooler with a front mounted rad may seem more complicated than air/air, and it does involve more compnents, nore work and more cost initially. But I think that in the long run it would work out cheaper and less hassle than a rear mounted air/air intercooler, which you would probably be forever modifying/moving/adding ducts to etc. Having said that, I read somewhere that the chap (who's name eludes me) who twin turbo charged the V6 Alfa in his Stratos had an air/air intercooler mounted in the rear and was apparently achieving 50 degrees C max inlet temperatures at 1.5 bar boost. 50 degrees C at that boost requires an efficient turbo and an efficient intercooler - so it is possible........

There is a forum member in Cyprus who has also made the same engine & turbo choice you are considering (Panos?) so it must be worth picking his brains.

A water/air charge cooling system, if properly designed and implemented will, in theory, give lower inlet charge temperatures at a given boost that air/air intercooling can ever achieve. That directly equates to higher engine outputs for a given boost level as charge density is increased.

Ford on their WRC Escorts cars used to have both air/air and air/water charge cooling, mainly because at relatively low forward speeds for given engine ouput requirements the air/air intercooling is not efficient enough. Another option, but obviously at higher cost.

Whatever you choose to do, please keep us posted,

[CorseChris]

I'm hoping to progress my Eaton M90 installation a bit more now the motor is in the car and I'm running it in. Basic plan is for a billet cam cover with a flat top on the front bank, and bolt the blower to the top of that. I started thinking about an M045 (bought 2 in fact) but really, it's a bit too small I think. Then I got a couple of Eaton M112s (Jaguar XKR) but they are too big for the modest boost I'm looking at. Finally ended up with an M90 but an M62 would be good too, unless you want monster boost. Aiming for about 8psi or so (as much as it'll take without detonation on a 10:1 CR anyway - time will tell). I'll be using an air/water charge cooler and up-stream TB, with blower bypass. Will be using an Emerald M3DK for management. This on a 12V V6 BTW. I didn't want to go for LC pistons as if I find the blower doesn't work as I'd like, I can remove it all and go back to nat. asp. Engine spec is C&B 'mild road' cams (very close to S spec), DIY port-matching (needed doing!), 10:1 CR as I said and a 3-angle valve seat cut. Otherwise stock.

Alternative turbo motors is certainly interesting and if you can manage the cooling problems in the Strat shape, then it might be a great way forward if you fancy that sort of idea. It can be done of course, but it's fraught with problems if other folks experiences are anything to go by. Neil Simons had lots of trouble sorting his cooling problems with his V6 turbo...but he did crack it.

[Martin K]

Chris

I think that an M090 running at such low boost would be rather inefficient. It's a bit too large.

For 8 psi boost it would have to be geared at 1.44:1 crank speed. This means it would be running at less than 8000 rpm at engine speeds below 5600 rpm. The M90 has an upper speed limit of 14000 rpm - the engine would have to be spinning at over 9500 rpm to reach that!

The M062 geared at 2.16:1 would be better suited to this boost level on your engine, if you can live with the engine working from 4000 rpm and with a rev limit of 6500 rpm so you don't overspeed the supercharger.

[CorseChris]

Quite agree Martin...but I got an M90 for peanuts and while the efficiency will hit me at lower revs (a bit) it shouldn't be a big problem higher up the range. In general use (road, not race, in my case), I'll probably be running at pretty much the most efficient region if my sums work out...I don't need to reach the blowers max revs to get boost, and anyway, the heat input rises sharply in that region.

...but time will tell. 8psi is pure guesswork on my part (as is the whole thing really) - I might even get away with 10psi before detonation becomes an issue. The Jags run 12 psi with over 10:1 IIRC. I know they are a better design than the Alfa but who knows until I try it. If it comes off, I'll have installed the thing for about £500 all-in. If it fails, I've still got a motor that should make an honest 200bhp nat asp

FWIW, I got nearer to 1.6:1 as a ratio with the M90 for 8psi and that assumes no losses, so a bit higher would be better ?? I could easily be wrong though...I often am.

The grand plan is to set the car up on the Emerald nat asp, then re-map under boost. At least I will know for sure what gains/losses have been made. A quick-change pulley set should help on the day.

I know what I'm doing isn't ideal, but I can't/don't want to afford new blowers etc etc. so I'll try this. Keeps me amused and as you probably know, I'm not shy about admitting it if it all goes wrong!

[strat6v]

I'd figured on mounting my blower where the aircon pump is sited, bit of a heavy piece of kit so better off low down. this placement throws up a few headaches, one being the front engine mount which needs reworking and the other is the front bank header which needs turning up slightly, probably better to turn out level and then over the top of the gearbox.

The blower is a large lump and is a very tight squeeze in the hawk chassis, gives about 25mm clearance from the chassis rails in front of it. It has a geared drive system that cleverly has the chargecooler pump incorporated, which also acts as watercooling for the gear assembly :cool:

When looking for sizing calcs i worked out that i needed a 1.6l volume per revolution of the blower. I ran this by a tech at lysholm (manufacturer) who then advised that it would be running at the upper end of it's efficiency and i would be better opting for a 2.3 l/rev and running it slower. Seems a lot on the big side but, after checking my specs, he assured me it was the best option and with it being an efficient design would still be better than the smaller unit.

I've planned on fitting a full width baffled fuel tank behind the sloping bulkhead to centralise mass a little more and fit the chargecooler and air filter box where the fuel tanks were, filter on the passenger side to suit the blower inlet and the charge cooler on the drivers side. Yes i know that seems arse about and would create a lot of ductwork but i thought about fitting the plenum the other way around, over the front cylinder bank ;) That would keep the ducting very short and easy to plumb a bypass valve too, hopefully controlled by the ecu. Many of the japanese 600 sportsbikes have throttle bodies of a suitable size (38mm) for a bypass valve and have a secondary butterfly operated by a stepper motor, should be just the ticket.

I reckon the best bet would be to draw it all up first before fabricating anything, should save me from a few cockups.

Any comments/thoughts?

[CorseChris]

It is interesting to see such a variation in figures for these things. The 4.0 Jaguar uses an M112, the 2.0 Mercs etc use an M45 and sometimes an M62, the 3.6 Fords (US) use the M90. All seem to run different levels of boost. Some have decent charge cooling, some have none.

I was going to copy your idea for a bypass John..until I got the M90 which came complete with bypass, TB etc. I'll stick with a vacuum operated bypass for now I think and see what happens. Should work fine as that's what the OEMs use. Minor detail really, but worth trying to get right.

I can't put the blower where the A/C comp goes...cos I have an A/C comp there of course. No way of putting anything aft of the motor unless I sacrifice the boot and move some chassis rails, which I don't want to do, hence my less-than-ideal location on top of the motor. Makes plumbing a bit easier and drive a bit harder.

The GSXR 600 TBs I used for the Westy have the secondary butterfly operated by a voice-coil actuator rather than a stepper...but I reckon that'll be even easier to operate.

I got an electric charge cooler pump from a VW something or other but have yet to decide where the water rad is going to go. Up front is highly unlikely, so it'll be a bit compromised. I still like your idea of building it into the rear spoiler but can't bring myself to take a hacksaw to it......

[strat6v]

Buy a second spoiler and cut and shut it, thats unless the other is glued to the rear end.

Shame my blower didn't come with the oem bypass valve, never mind. I'll need to pick your brains re the wiring of the stepper motor though. Just hope there are enough configurable input/outputs on my ecu.

Did you see the post i left about the Jim K forged conrods at £500.00 the set? Have a look on the bulletin board.

[CorseChris]

I did see those, look nice...but not until after I'd assembled the motor....so they'll have to wait. Mind you, I suspect the power levels I'll achieve won't be bothering the standard internals overly much.....I was already hesitating about sticking with the 12V after seeing your GTA motor. If I'd ended up with forged pistons, fancy rods, new blower etc, I'd never have got even this far and would have probably gone for a stock 3.2 GTA as it would have been way cheaper.

Spoiler is bolted on with just a bead of goo to keep the water out, so removing it is an option. I'll try Plan A first and see how it goes (Plan A is to use one of the side ducts on my car and make sure the air can only go through the rad, fan assisted of course or I'll be onto a loser straight away. I think I'll use a 156 oil cooler rad I got as a first stab). I can monitor inlet air temps with the ECU so it'll soon become obvious if I got it wrong.

I forgot to say yesterday BTW - Martin, thank you for the input! Always welcomed.

[Martin K]

FWIW, I got nearer to 1.6:1 as a ratio with the M90 for 8psi and that assumes no losses, so a bit higher would be better ?? I could easily be wrong though...I often am.

Did you assume a VE of 100%?

On a 2 valve per cylinder setup, do your calculations using 93% VE, or with a positive displacement supercharger you will find you have more boost than you expect.

Also I have seen two different flow charts for the M090 - so maybe we are working with different displacements!

[CorseChris]

Hi Martin. I did, but there are so many variables that I don't really stand a chance of figuring out (loss of boost due to cam overlap, blower leakage etc), that I decided to take a more empirical approach based on very basic calculations. Kind of 'blow it and see'

I've seen loads of different charts as well, so it's all a bit hit or miss really. I'm using an early blower from a SuperCoupe so it'll be less efficient than the latest 5th gen ones. Shame the M45 was too small as I have an almost new one of those (ex-Mini), and I have a late-ish M112 with the teflon rotors. Did toy with the idea of putting the M45 on the Westy but I think I'll drop that idea!

Time will tell and I promise to post up the results once I get them, good or bad. It'll be a while yet as I'm still running in the new motor on Motronic, so have yet to fit the blower & Emerald. I think the billet cam cover might be forthcoming soon which is a big step forward. I have the old 12V motor I took out the other week to use as a jig so I can get it all mocked up on the bench first. I'm determined to make it a simple bolt-on job with minimal mods to the car, which will no doubt add to the work, but it gives me an easy way back if it all goes horribly wrong. Worst-case will be I end up nat asp with the Emerald, so I lose the AFM and get optimised igniton & fuel maps, which has to be worth a few bhp.

Greg Gordon, who does a fair few Alfa blower kits thinks I should use an M62 and LC pistons as well, so I know I'm flying in the face of experience here.