Turbo to supercharger swop

[popuptoaster]

Apart from the obvious brackets and pulleys whats involved in removing a turbo and fitting a supercharger?

Almost next on my 940s list is a bigger turbo and while I quite enjoy the rush of the turbo coming on boost I still don't like it as much as the instant go you get from a big engine so i am pondering fitting a blower instead.

I assume (large assumptions from someone who knows little about turbos and nowt about mechanical blowage) that I can whip the turbo off and knock up a new exhaust fannymould, mount the blower and with suitable pipework mods plumb it in through the existing intercooler/manifold arrangement?

Is it that simple? What size blower are we talking for my 2.3, it should end up with about 250bhp at the crank, maybe a bit more, but i'm not planning on going mad with it.

[ettorebugatti]

I think that the LH injection system should be able to cope with this change if you keep close to stock boost.

[kerrly]

I'd be tempted to look at a Eaton chargers although I do recall seeing a chap with a 240 2.3 with a supercharger from a Mazda xedos ?

[jasonj]

An Eaton M62 would be about right. Easy and cheap enough to pick up. They were used on a lot of Mercs.

[popuptoaster]

Apr 26, 2012 23:22:35 GMT ettorebugatti said:

I think that the LH injection system should be able to cope with this change if you keep close to stock boost.

Its already at three times the boost it started at, limited now by the ECUs fuel cut which will be sorted next, but after that I cant run much more boost through the stock small turbo.

Apr 27, 2012 10:31:29 GMT jasonj said:

An Eaton M62 would be about right. Easy and cheap enough to pick up. They were used on a lot of Mercs.

I'll keep digging through the internets.

Apr 27, 2012 10:31:29 GMT jasonj said:

An Eaton M62 would be about right. Easy and cheap enough to pick up. They were used on a lot of Mercs.

Easy and cheap sounds good, i'll investigate.

[froggy]

if you use the m62 you will need to have a plan to deal with surge if you leave the throttle in its original position

[popuptoaster]

According to Google (i did mention I don't know anything about Superchargers, ) compressor surge is caused by certain RPM and throttle opening combinations and can be cured by fitting a blow off valve to release unwanted manifold pressure, is that what your talking about?

[froggy]

Yep a combination of bypass and blow off valve works well . The bypass stops the charger pumping air out of the dump valve under cruise conditions .

Most oe systems have the Throttle upstream of the blower so it runs in vac so can't surge . Shut the throttle against a mechanical pump doing 10,000 rpm and the pressure spike can make a mess . The bypass gives the brief pressure spike you will still get leaving the throttle in its original place a route around the blower rather than trying to go backwards through the charger .combined with a vac fed dump valve the air has plenty of escape routes . Chargers are louder with the throttle after though .

[popuptoaster]

Ok cool, this is the stuff I need to know.

It may all seem a bit over complicated for a cheap old 940, but If it all works out i'll be looking at doing it again but having the lump in something more interesting so its kind of a test bed.

[hutchnike]

What size turbo are you running ATM ? I have found a TD06 20G spools up really quick and max's out about 380/400 Hp
How about fitting a Blower as well ? just use a switch solenoid when the boost gets near the turbo's ramping revs ?
Seen it done on a few cars, instant boost off the blower then the turbo takes it the rest of the way.
Looking at the power you want to run at the crank then maybe a £60 CT20B off a celica GT4 or MR2 Rev 3 280/300 or the slightly smaller one off the Rev 2 and ST185 Celica Gt4 Max's out at about 230/250

Hutch

[popuptoaster]

Stock turbo, apparently loses lots of efficiency and starts to heat up at 16psi, have been recommended to go up to a T34 by a man who knows these engines for the power I want.

I'm want to avoid the extra weight and complication of a compound charging, it'll just be overkill, I could make 500bhp with a socking great turbo on this lump, its been done a lot in Sveeeeden and the US.

However its not just down to that, while I quite like the feeling of the boost coming in for me its far less useable than the instant torque you get from a bigger engine so i thought i'd have a go with a super charger, I'm not so worried about the extra drag and power loss at the top end as i should be able to get the power i want without a problem, not really after ultimate power.

I want instant oomph without chucking it down a few gears and if my plans come to fruition it'll be in a fairly light car so a large dollop of power arriving all of a sudden is counterproductive and can actually make you slower. I had the same problem with my 24v cortina as it came on cam at 3200ropm it just broke the wheels loose, even at 70mph in third gear, which combined with the heavy engine in the front had me going sideways up the A127 while accelerating "briskly". :S

[claymore]

All I use is a recirc valve off a Mitsubishi vr4, and my car runs just fine, and has done for the past 12 months.

[CR500Dom]

I've got mine set up with a big recirculating dump valve.
Plumbed in post charge cooler back to pre charger basically between TB and charger.
On the next one, as I'll be running ITBs and a charger, I'll run another FBW throttle body as the bypass, ecu controlled, so I can effectively throttle the bleed off and control the manifold pressure.

[bornretro]

i personally would stick with a Turbo on such a small engine rather than supercharging it... you lose a certain amount of the curve at the bottom end too with a supercharger as it also needs effort to be spun up and the effect of "instant boost" is a little bit of a Myth, especially on a relatively small 4-pot....ask Lancia nuts about the Beta Volumex plus having owned a Polo G40 and various VW G60's myself, yes the power is there but its nowhere near as efficient as a turbo.... trust me, put a Ford 302 or 351 windsor V8 (both been done..) in it with the right parts and youll forget all about Forced induction forever...

[popuptoaster]

Apr 30, 2012 20:15:24 GMT bornretro said:

I personally would stick with a Turbo on such a small engine rather than supercharging it... you lose a certain amount of the curve at the bottom end too with a supercharger as it also needs effort to be spun up and the effect of "instant boost" is a little bit of a Myth, especially on a relatively small 4-pot....ask Lancia nuts about the Beta Volumex plus having owned a Polo G40 and various VW G60's myself, yes the power is there but its nowhere near as efficient as a turbo.... trust me, put a Ford 302 or 351 windsor V8 (both been done..) in it with the right parts and youll forget all about Forced induction forever...

I've had big engines in light cars before, they end up feeling like your a driving a hammer, i don't consider a 2.3 to be particularly small either. While it may not be large compared to a US V8 it also takes up less space, weighs less, uses less fuel, is cheaper to replace if needed, easier to work on in the engine bay.

I doubt very much if the Volvo lump is going to have any trouble spinning the size supercharger I'm looking at at low revs, its already a nice torquey engine and with the turbo on hardly ever comes on boost in normal driving and it copes fine lugging the 1400kg 940 around.

As I said before I'm not trying to ring every last BHP out of this engine, i want a nice easy to achieve 250bhp without the sudden boost of a turbo or lumpy cam kicking in half way up the rev range.

Its ok saying "just drop a V8 in it" but compared to the cost of buying a second hand supercharger, some pulleys and bits of pipes your probably looking at 10x the price by the time you've tuned it, found a manual box, sorted out the exhausts, beefed up the suspension to cope with the weight plus the time and effort required to physically fit it.

[popuptoaster]

Apr 30, 2012 20:15:24 GMT bornretro said:

I personally would stick with a Turbo on such a small engine rather than supercharging it... you lose a certain amount of the curve at the bottom end too with a supercharger as it also needs effort to be spun up and the effect of "instant boost" is a little bit of a Myth, especially on a relatively small 4-pot....ask Lancia nuts about the Beta Volumex plus having owned a Polo G40 and various VW G60's myself, yes the power is there but its nowhere near as efficient as a turbo.... trust me, put a Ford 302 or 351 windsor V8 (both been done..) in it with the right parts and youll forget all about Forced induction forever...

I've had big engines in light cars before, they end up feeling like your a driving a hammer, i don't consider a 2.3 to be particularly small either. While it may not be large compared to a US V8 it also takes up less space, weighs less, uses less fuel, is cheaper to replace if needed, easier to work on in the engine bay.

I doubt very much if the Volvo lump is going to have any trouble spinning the size supercharger I'm looking at at low revs, its already a nice torquey engine and with the turbo on hardly ever comes on boost in normal driving and it copes fine lugging the 1400kg 940 around.

As I said before I'm not trying to ring every last BHP out of this engine, i want a nice easy to achieve 250bhp without the sudden boost of a turbo or lumpy cam kicking in half way up the rev range.

Its ok saying "just drop a V8 in it" but compared to the cost of buying a second hand supercharger, some pulleys and bits of pipes your probably looking at 10x the price by the time you've tuned it, found a manual box, sorted out the exhausts, beefed up the suspension to cope with the weight plus the time and effort required to physically fit it.

[bornretro]

Sorry about the "just drop a V8 in it " quote.... It's just that I do it all the time so is second nature :-) ... When I can get them off my old computer I will post pics of a V8 Nissan MICRA and lots of other looney stuff plus my Canadian cousin's Viper engined Volvo 262!! Forced induction is all good a I respect that but y can't beat pure cc's... All the best in your project :-)

[popuptoaster]

I'm not a stranger to engine transplants either, but I don't fit a big lump for the sake of it.

I'm always trying to get maximum power per pound note while still having a daily useable car, i usually cant afford to have a toy.

Whatever I build has to be able to do the school run, go to the shops, take us on holiday, take wardrobes up the tip etc etc

There is a difference between making something crazy and making something that still works as a car, hence you never see any of my stuff in the weeds, done that, causes to many issues for a daily car that has to do family duties.

Same with nutty engine transplants, plenty of room in a cortina for a big V8 but i went for a 200bhp 24v V6 because I knew that fitted right it would still hit 30mpg and was fast enough, handling was compromised but it was still useable everyday.

Whatever happens to the Volvo engine will probably get copied and fitted into something that has restricted room in the bay and doesn't weigh much, so while its entirely possible to fit big engines in small cars in this case I'm not interested, hence the thread being about superchargers.