Wow what a response !

[k10]

Well cheers to everyone for there replies. Perhaps I should have expected a rant fest as I know engine conversions always promote a lot of debate between the purists and the V6 and turbo brigade.
They are all great conversions and I don't want to debate what's better etc... What I really want to know is this, I've got £600 to spend on an engine. I can get a 20 valve silvertop for this money. I've been told that the silvertop is slightly more robust than the blacktop, although the blacktop has a few more bhp. I love the Mk1 for it's revvy nature and it's handling. I've had faster cars in a straight line, M535i's with race cams loads of E30 325i's a TVR Chimera HC etc... But I keep coming back to the Mk1 for it's bang for the buck as the yanks would say.. It's just a fun car to thrash and they are reliable and sooo cheap... Now I'm a tight wade and my wallet is rarely seen in public so I don't want to shell out £3-4K on a conversion as Paul Woods suggests... So for my £600 I can appear to get a silvertop engine box and ECU and I've changed a few engines before but don't want to get into welding engine mounts etc... I want it to be as easy as possible as I'm lazy also..So back to my questions.
It would appear with a silvertop I can get the job done for £600 notes and get 20-30 bhp more grunt and still have the 4age revving to 8000 rpm. All I need to know is is the silvertop much heavier to offset the power and handling? If so how much in Kg? This will be in a track car remember and all I want is a bit more grunt on the straights to hold off the 325's so I can eat them up in the corners...So how much extra does it weight? And do I need any other costly things to make it run like specialist wiring to make it run which I believe someone referred to in the thread?
Thanks all....

[Moustachio]

Dude, there is going to be naff all difference, the 20v has got more valves etc (obviously), but lighter internals (iirc), both iron blocks... probably weighs less than a 4agze (i.e. no supercharger, intercoller etc) but I may end up sitting corrected on that

seriously you will not notice a difference, it will not upset balance etc.

(A v6 or turbo doesn't and by that logic a 20v won't)

If you can get the conversion done for £600... well firstly I'm amazed and secondly bite whoever's arm off is offering the conversion at that price!!!

Go for it.

mk1 + more power =

[PW@Woodsport]

If you can get a 20v supplied, fitted and wired for £600 i'd rip the guys arm off, wether you feel the difference or not, at that price i wouldn't care.

I couldn't even supply the engine at that price or anywhere near it. You really are much better off doing that than spending it on your 16v, go for it

[Jaspa]

This explains it for a blacktop, shouldn't be that different I would imagine.

http://www.padandwheels.com/mr2/index.html

[Bender Unit]

The differences between the ST and BT are negligible – people make claims about the durability of each engine yet most of these are pretty subjective.

One advantage to the BT is that its MAP so you can kick the airbox off and enjoy the noise from the induction roar.

For £600 sheets I would still consider whether its really worth it – if your 16v is healthy then the performance differences will be minimal. You won’t be getting 30 / 40bhp more grunt – they don’t have that sort of power, and quite seriously even that power difference is marginal – especially on track.

£600 could be better spent elsewhere, or put towards tuning of the 16v. Have you considered turboing the 4age, that can be done very cheaply and as long as your not shooting for the stars you can retain the 4age’s key characteristics but benefit from some more poke. I had a run in a mates turboed AE86 a few weeks back – only pushing 190bhp, but the engine went like a stock unit but with some more guts – thing is though on track chasing him with only 130bhp, despite his 60bhp difference he would only gradually pull away on the long straights!

If your struggling to keep 325’s at bay on the straights you’re doing something wrong though!

I have a mate who spent a some good money tuning a ST and only got 150 out of it, he then spent a insane amount of money tuning a BT and only got 190 out of it. He has said if he could do it over again he would just work with the 16v as parts and tuning is cheaper and for the same costs you can get comparable performance.

[MartG]

IIRC a fair proportion of the added power of a blacktop ( as fitted in an AE111 ) compared to the silvertop ( in an AE101 ) was down to the freer flowing exhaust on the later car anyway, so in an MR2 with a non-cat exhaust you should see pretty close to the quoted 160bhp of a new engine.

As for weight, I'd be surprised if the 20V was more than a couple of kilos heavier than the 16V, as pretty much the only added bit is the VVT gubbinry in the head, which is probably balanced out by the loss of the T-VIS and plenum on the 16V.

As someone mentioned on the other thread, the standard gear ratios of the C52 gearbox may not be ideal for the engine, but you can always tweak the ratios a little by playing with your tyre profiles

[k10]

Hello all, in reply to doing something wrong against 325's on the straights, I've raced and owned 325's and sorry to upset but a low compresion 325 has 170bhp in a shell with similar weight to a mk1 with 120 bhp so that 50 bhp and straight 6 grunt counts quite a bit on the straights can't see how you can make that disappear??? Cornering is a different matter altogether however...
Paul.. I never once said I could get a silvertop supplied and fitted for £600 notes.. I've always stated in my threads that I could buy one with gearbox and ecu for this price and intend to fit myself. This is the main point of my thread. I want to know if I need any specialist wiring etc.. Or whether the silvertop will just plug and play in an aw11 with its own ecu?

[eRATic]

from what i remember you need the itbs and full engine wiring loom.

best bet would be to sell your mk1, get over to TB and buy BSMs mk1 with a rev 3 turbo conversion for £2000. needs finishing off but nothing too major.

[PW@Woodsport]

Paul.. I never once said I could get a silvertop supplied and fitted for £600 notes..

Er i read this as meaning you could....

It would appear with a silvertop I can get the job done for £600 notes

I want to know if I need any specialist wiring etc.. Or whether the silvertop will just plug and play in an aw11 with its own ecu?

Yes it's specialized, and will not plug straight in.

[k10]

Hi Paul it helps I find if you concentrate on reading the whole sentence or paragraph and then putting it into context.. For example the selected quote you put it was part of a longer sentence which clearly refers to me doing the job myself... see quote reproduced below:
'So for my £600 I can appear to get a silvertop engine box and ECU and I've changed a few engines before but don't want to get into welding engine mounts etc... I want it to be as easy as possible as I'm lazy also..So back to my questions.
It would appear with a silvertop I can get the job done for £600 notes'

[PW@Woodsport]

My mistake then, it's just the way it read to me. Either way it's a very cheap engine.

Good luck