20v conversion

[rolandfantom]

This is a speculative question as to why people have gone for this conversion - there doesn't seem to be a huge BHP difference, I'd say the 20v engine is probably considerably heavier, and the engine configuration would affect the handling too.

I'm just interested as to why people have chosen this conversion.

[MartG]

The 20V weighs about the same as the 16V engine ( it's the supercharged one that weighs more ), so the additional 40bhp is quite useful

[rolandfantom]

The 20V weighs about the same as the 16V engine ( it's the supercharged one that weighs more ), so the additional 40bhp is quite useful

The 20v engine/box weighs about the same as a 16v/box???? I'm not doubting you, but I find that hard to believe.

[MartG]

Most conversions retain the existing gearbox, so that isn't a factor. As for the engine, there is very little there to add weight compared to the 16V

[rolandfantom]

Most conversions retain the existing gearbox

Ah... the pictures I'd seen had the 20v box, which is why I questioned the weight increase.

The dimensions of the short engine look much larger on the 20v too, I wonder how that affects the weight distribution/handling?

[MartG]

The dimensions of the short engine look much larger on the 20v too, I wonder how that affects the weight distribution/handling?

The block is identical to a 16V one of the same age, and had no major differences from earlier 7-rib block variants - if anything the bottom end is very slightly lighter due to lighter conrods used on the 20V. The major differences are restricted to the head - the ITB setup replacing the ( heavier IIRC ) manifold & throttle body, and the internal changes to the head itself.

As for the handling - if putting a 3S-GTE 2 litre turbo lump into one doesn't affect the handling too much ( as demonstrated by several people on trackdays with their Mk1.5s ), then swapping for the 20V 4A isn't going to do much harm.

[rolandfantom]

As for the handling - if putting a 3S-GTE 2 litre turbo lump into one doesn't affect the handling too much ( as demonstrated by several people on trackdays with their Mk1.5s ), then swapping for the 20V 4A isn't going to do much harm.

That kind of leads me back to my original thoughts, which is why wouldn't you go for one of the other conversions (that ultimately provide more power). I'm not saying that BHP is everything, in fact it isn't, tractability is, but if you can get an extra 50-60bhp and an easier life (given that the 1.5 conversion has been done more times), why wouldn't you?

I like the idea of a 20v conversion, but I'm not sure whether I'd feel disappointed with the gains when it was completed.

[MartG]

The big advantage of the 20V conversion is that it is virtually a drop in replacement - unlike the 3S-GTE swap where you need to grind off the existing engine mounts and weld in new ones as well as figure out intercooling etc. Even putting a 4A-GZE in needs an intercooler or chargecooler installing which complicates the install a little.

[rolandfantom]

The big advantage of the 20V conversion is that it is virtually a drop in replacement

Ah, the reason for the 20v begins to make more sense now. What tuning opportunties exist with the 20v - presumably people have done the 20v turbo conversion too?

[MartG]

Using a 20V as the basis for a forced induction engine isn't a very good idea - to enable it to rev higher than the 16V it uses lightened internals ( conrods etc. ) that don't stand up to the additional stresses very well. Also the 20V head doesn't give much improvement over a 16V one when using forced induction, as the extra valve is designed to improve breathin in NA use, so the additional cost of the 20V engine is pretty much a waste.

However I think it has been done in the US ( where 20Vs are more common ) using a GZE block with the 20V head.

[Jim-SR]

tensile forces are for more destructive than compressive ones, the 20V internals are equally (if not better) as well equipped as the 16V internals. low pressure turbocharging has been done successfully on both engines, but for what it costs it totally isnt worth it. to do the job properly costs more than swapping in a 3S-GTE. if you cut corners to save money it will cost more in the long run.

the 20V swap is done because its relatively easy, retains the normally aspirated nature of the MR2 (which is way better than any turbocharged version can ever hope to be. its just not cost effective to stay NA unless you go V6), doesnt add weight, and can be done for sensible money.

a 3S-GTE swap is also relatively simple nowadays since there is such a wealth of DIY information available. it can also be done professionally by Woodsport for not huge amounts of cash for what youre getting. they can also do V6 swaps! and this swap doubles your horsepower straight out of the box, whereas a 20V swap is only a 35% increase. this does add a fair amount of weight though, i cant remember the exact amount but 80kg seems to ring a bell. in the grand scheme of things thats the same as a passenger though, so its of little consequence and the handling is barely affected. you can easily compensate for it with suspension upgrades.

if youre looking to do a swap then youve just got to weigh up the options and your preferences. if you want to stay NA and do it cheaply then the 20V is a fairly easy swap. if you want outright power then youve got the 3S-GTE turbocharged or a V6 NA (or even better, supercharged!). theres now an AW11 swap for every occasion the 2ZZ-GE is the coolest swap though IMO. it retains the natural feel of the MR2, revs higher, reduces weight, comes with a 6 speed box, and makes 190bhp with VVTi. however its generally a more expensive engine and a hard swap due to OBD-II electronics (it physically bolts in very easily, the wiring is the tough part).

[rolandfantom]

a 3S-GTE swap is also relatively simple nowadays since there is such a wealth of DIY information available. it can also be done professionally by Woodsport for not huge amounts of cash for what youre getting. they can also do V6 swaps! and this swap doubles your horsepower straight out of the box, whereas a 20V swap is only a 35% increase. this does add a fair amount of weight though, i cant remember the exact amount but 80kg seems to ring a bell. in the grand scheme of things thats the same as a passenger though, so its of little consequence and the handling is barely affected. you can easily compensate for it with suspension upgrades.

Which conversion adds 80kg?

[Jim-SR]

3S-GTE. im not 100% sure on the 80kg, i just seem to remember that number. it definitely adds quite a bit of weight, i cant remember exactly how much.

[SteveM]

the 2ZZ-GE is the coolest swap though IMO. it retains the natural feel of the MR2, revs higher, reduces weight, comes with a 6 speed box, and makes 190bhp with VVTi. however its generally a more expensive engine and a hard swap due to OBD-II electronics (it physically bolts in very easily, the wiring is the tough part).

[/quote]

Does it bolt in without having to cut out/weld in new mounts Jim?

[System-G]

The 2ZZ would need mounts, not sure about anything else.

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My personal ideal swap would be the 2.0 3S-GE BEAMS - +/- 210bhp N/A with 6 speed possibilities. Also tons of reliable modability

I drove a MKII Rev5 and an Alteza (Lexus IS200) with one of these engines a number of years ago and really loved the engine

Only problem is the engine/box would not be the cheapest about and it would need a fair amount of bodging to get fitted/right for the AW11...
AND
I can think of loads more "better" things to do with the money

[PW@Woodsport]

G what 6 speed possibilities do you mean for the beams conversion mate? As far as i'm aware there aren't any?

I will keep my 2p short and sweet as this is my mastermind specialized chosen subject

In MY opinion, the 20v is a complete waste of money, people only go down that route for the ease of install, sure it will be revvier but ultimately no extra bang for your buck.... and it costs quite a lot of those!

I have built and driven just about every combo of engine swap there is for the mk1, and for me the one that just ticks every single box is the 1mz-fe v6. It won't have the outright power or tunability of the 3s-gte swap which is just a total animal (think Mk1 SC x2, feels like it!) but the 1mz-fe in a mk1 is just sublime, so much torque, smooth as silk and an exhaust note to die for. The best bit of that swap for me is the weight, there is no noticeable felt increase or upset to the handling at all with that engine, it really is nice and light, sure it's heavier than the 4a-ge but nothing more than a boot full of shopping.

Beams mk1 would be awesome but i think that engine would be slightly heavier than a 1mz and has less torque (or less of it available throughout the revs) , 1mz gives full torque by 2500rpm

Together with the lovely LSD and 5th gear extension upgrades that are available for the Mk2 NA gearbox (used with the 1mz, could also be used on the beams) i think it is the perfect combination, and i was always a die hard 1.5 fan.

Whatever you choose i would not sink my hard earned into a 20v, ultimately disappointing for the invested time and money.

So much for keeping it short and sweet

[Jim-SR]

the 2ZZ-GE is the coolest swap though IMO. it retains the natural feel of the MR2, revs higher, reduces weight, comes with a 6 speed box, and makes 190bhp with VVTi. however its generally a more expensive engine and a hard swap due to OBD-II electronics (it physically bolts in very easily, the wiring is the tough part).

Does it bolt in without having to cut out/weld in new mounts Jim?[/quote]

3 of the 4 "engine" mounts are on the gearbox. all of the C-series gearboxes have the same mounting locations. so you literally just have to unbolt the front and rear, and left side mounts from your existing gearbox, bolt them onto the 6-speed celica/exige gearbox, and thats it. they they bolt straight on to the existing mounts on the chassis!!

the only mount that needs modifying is the engine side mount, which needs a couple of holes drilling iirc. again, its an easy modification.

none of the chassis brackets need any kind of modification. you could literally bolt a 2ZZ-GE into an AW11 in about 10 minutes more than it takes to bolt a 4A-GE in!!

the hard part of the swap is the wiring. i wouldnt even know where to begin with it, which is probably the only reason i havent done the swap already lol.

[System-G]

I think some of the IS200's / Altezza's have a 6-speed option.

Have a read of the AE86 conversion in this thread. The owners seem very clued up and quotes a 6 speed box. Looking at the pics though (Page 6), I'm not sure the BEAMS would fit with the box being discussed in an AW11.

Good to see a car of similar age to the MK1 being built/prepped properly from the ground up

Certainly not cheap though

http://www.lancerregister.com/showthread.php?t=295818

[PW@Woodsport]

Altezza is inline mounted though G, not transverse?

[System-G]

Yup and the reason I figure it's gearbox wouldn't fit...