Gti6 Pros And Cons Against Mi16 Pros And Cons

[Veero 1]

After all the grief with my Mi16 loom and getting it running right I have been toying with the idea of trying a GTi6. I've seen supposedly good engines going for a few hundred quid with most sensors etc all attached.

 

Now I am well aware of the potential issues with the Mi16 engine, oil surge etc plus the fact the engines are older and now good components such as AFMs and throttle bodies (yes you can convert to others as I have a GTi6 one on there but it's a ballache as the TPS doesn't fit properly and is wedged against a very hot rad top hose which is far from ideal) are getting harder to find. Also it only seems to have a very basic diagnostics system which despite it not working it won't even hint at what might be wrong. Also ECUs for the Mi are becoming impossible to find unless you want to spend £120 from the likes of Spoox.

 

Anyway I am not really bothered about which is the better engine. I have heard alot about the '6 engine in a 205 and after all it's fairly similar, but will have some differences. I'm sure they are just as lairy to drive (surely maybe moreso having a few extra horses?) so I'm wondering if it is worth having a go at doing another conversion. I do have a good Mi16 engine, fully rebuilt etc etc etc a few years ago but I am always worried about things like oil surge on long left handers but just can't seem to get the damn thing working 100% reliable 100% of the time. I would like just a more bullet proof engine, and the '6 having the baffled sump and being a bit more modern it potentially would be more dependable.

 

I haven't paid any attention to the detail required in a '6 conversion but assume it can't be far different. So what do I need to do:

 

-Do the standard 205 1.9 shafts fit the 6 speed box?

-Are all the angles of the engine primarily the same, ie is rocker cover to master cylinder clearance similar and bulkhead to rocker cover similar etc?

-Electrics wise how do you get the rev counter working with the 205, I vaguely remember something about a conversion circuit? Is the speedo drive the same in the 2 gearboxes?

-How do you get the 6 speeds working from the 205 gear shift system, does it need much jiggery pokery or could I just stick with my 5 speed Mi box?

-Does anyone know the actual weight difference between the 2, can't be more than a few kgs, curiosity more than anything?

 

I'm not a racing driver and won't be making a monster power engine, I just want a car I can hop in knowing full well it will start every time, idle spot on and be thrown around any corner without fear of a big end letting go. So long as it puts a smile on my face and doesn't sit there hunting for idle in traffic then that fits the bill.

 

Is it worth the effort? (Bare in mind I love tinkering with things so don't think the actual effort of doing this is a chore) As I said in the title, please don't make this an Mi16 vs GTi6 slanging match, I just want opinions on whether or not what I've said makes any sense.

 

Thanks

Veero

[Batfink 201]

Each engine has its strengths and weaknesses mentioned already in many threads so I wont go there.

I think the gti-6 is the natural progression in our engine choice as mi16 ones get rare.

One thing I will say is, forget the 6 speed. I've done it and although 6 gears is nice, the extra weight and s*it turning circle is not. I felt a 1.9 box with 1.6 final drive was as much fun and far simpler.

The gbox conversion is piss easy though. I did it lol

The simplest way is to fit the 205 clutch arm and lever so you use an mi16 or gti clutch and flywheel

You also need to change one of the gear selector arms to a 205 one, and swap the speedo sensor to a 205 one.

You will also need a be1 lever/cable as the gti-6 box has lift up reverse.

Edited October 1, 2009 by Batfink

[brumster 135 1 Cars]

Urrgh, this one again

 

1) Don't believe every word you read about catastrophic oil surge.

2) Short of big power (190 plus) I'm not convinced the gti6 is automatically a better choice - XU10's have their fair share of wear and tear these days just like XU9's. If you're just looking at a straight swap, I think for road use the gti6 is marginally better, but I would factor this into any pricing up too. What I mean if, given the choice of an XU9J4 for £200 or an XU10J4RS for £500, I'd take the XU9 route easily.

3) I know it's big expense, but throttle bodies and mappable management can sort EITHER of these engines out soooo nicely, certainly worth thinking about

4) 6-speed box, honestly, I wouldn't bother. The engines will pull a little 205 with a 5-speed better, and you've got all the hassle around reduced steering lock and getting it through an MOT by making something to stop the wheel fouling the end of the gearbox. And less ratio choice on top. Just stick with a decent 5-speed box.

5) Weight difference, according to our resident guru DrSarty - 16Kg. Sweet fa really, in the grand scheme of things.

[Baz 421]

Agreed, oil surge isn't always as bad as some make out, it seems different from engine to engine in my experience.

Also, i agree about Xu10's being due a rebuild as much as any Mi these days, and bore-wear... chocolate valve stems & pistons etc etc i won't go on.

 

Things aren't that rare yet tbh, they're just demanding a slightly higher price seperately. Spoox are taking the piss, unsurprisingly.

 

Mi's are still King in my book!

[Baz 421]

Ooh, and also agree, TB's & management make such a difference...

[TurboSam 5]

I just want a car I can hop in knowing full well it will start every time, idle spot on and be thrown around any corner without fear of a big end letting go. So long as it puts a smile on my face and doesn't sit there hunting for idle in traffic then that fits the bill.

 

Sounds like the GTi-6 is the engine for you.

 

Mine has been converted for 2 years and has been spot on.

[James_R 3]

If you already have a Mi converted car I'd just pay someone to sort the electric end of it out and enjoy it, you'd have to be pushing some on the road (and really) to surge it. TaylorsPug, Miles etc... would be more than happy to do the work i'm sure.

[James_m 0]

I feel exactly the same way Veero. Personally, i find its the electrical problems that annoy me the most, honestly i think Motronic has had its day now, all the AFM's tend to overfuel and with no lambda sensor there is obviously no provisions to prevent it. I just hate the idea of the inefficency of the whole thing.

 

I think for me the next step is going to be an aftermarket ECU. Less parts to go wrong and every sensor value right in front of you on a lap top. Should result in much improved reliability from what i can see.

 

As for engine reliability, yes Mi16's have appalling oil surge which kills bearings, but from looking on here and occasionally the 306 forum, the Gti 6's seem to have a whole host of other more worrying problems such as dropping valves and a crap timing belt setup, but this is not first hand experience so purely rumour and probably selective viewing. It seems all the engines have there failings, you just have to be lucky!

[GLPoomobile 958]

I only skim read this, but the general gist seems to be that you have a few problems still to iron out, and you are worried about oil surge.

 

For the former, why not push on and try and iron the wrinkles (such as the TPS problem you mentioned), and if you feel you don't have it in you, I'm sure it would be childs play for some of our engineering boffins on here to do for you. Then why not spend a few hundred on a 2nd hand mappable ECU and get it mapped. You don't have to go to the extreme of ITBs, just ditch the AFM and Moronic (sorry, Motronic ). All of this should be cheaper than sourcing, refreshing, and installing a 6 engine.

 

As for oil surge, is it just paranoia on your part, or have you actually noticed the needle flickering when giving it death? If it's not regularly showing signs of losing pressure then why not just cast it to the back of your mind, and if it ever does let go, use it as an excuse to convert then rather than now.

Edited October 1, 2009 by GLPoomobile

[Batfink 201]

My Mi16 never surged once, and i drove it like a right pleb

[welshpug 1,662]

mine did, once, and that was the end of it! wasn't even driving like a loon, just a tightening curve on a left hand sliproad, but it was a tired 122k mile engine that hadn't been looked after.

 

the gti6 in there now doesn't, and has the same sump on it.

 

downsides, can't fit any decent cams in there without upgrading pistons, upsides, nice exhaust manifold and decent intake setup.

[Veero 1]

The thing is I am totally open to both sides of the argument. On one hand yes I have had a fairly decent running Mi for a number of years, I have probably done the region of 15k miles with it after I rebuilt it myself. Probably the worst thing to do at the time was to not redo the loom then when I converted it. The loom was a bodge but with it working it seemed silly to fix it etc. But yes I have tried to fix the problems of the Mi. Namely the 306 GTi6 inlet manifold and TB. Yes the TB is fantastic but the TPS does not fit properly and consequently moves itself eventually. (GLP I am an engineer and with my current job have the facilities to make good some of the things mentioned ) I love coming up with solutions or implementing solutions that other people have done on here to the little problems but there comes a point when I just don't want to anymore. I just want it to go and go right first time every time not wonder how it's going to not idle right or cut out next.

 

About the oil surge. I have seen it mentioned on here and I know a couple of people with Mi's who have had a big end let go. Before I did the conversion I was aware of it, I hoped a complete strip, chemical clean and rebuild would hopefully reduce the risk, but there was a long left hand corner off the A38 onto the A30 towards Exeter I drove down every day and after watching the oil pressure gauge drop like a stone the first time I went round there quickly I have ever since been worried about it. To my knowledge the oil pressure warning light has not come on in spirited use but it's still something I could do without the worry. I even had an 8v crank and rods to fit along with an XU10 sump and oil pump but that's an engine out job, while I'm at it why not fit something that has all that already? I would prefer to do a conversion and at least have a fairly solid engine to sell whole rather than give it away for pence because a big end needs replacing. But again on the flipside I do see the point of if it ain't actually broke don't fix it.

 

On the subject of paying someone else to fix it, well I'm sure there are several outfits around capable of locating and fixing the problem but at the end of the day they are probably far away and I am loathed to get it 'finished' by someone else after the time, effort and money I have already put into it, all for the some of the same worries to be there after it's 'fixed'.

 

So what sort of approximate cost would I be looking at for TB's + management + mapping? I'm guessing several hundred quid, perhaps £5-600? Surely for that I can get a GTi6 at least partially rebuilt, in and running if I am careful.

 

Another aspect I forgot to mention in my original post was the economy of a standard tune engine. I used to use my Mi as a daily driver for work that's how reliable it was and on the combined run over a week I had it up to 37 to the gallon. I seriously doubt TBs will get me anywhere near that. What approximate mpg would I be looking at for a GTi6'd 205 on a long motorway run say?

[Batfink 201]

Add about 800 or so to the cost of throttlebodies/ecu and mapping.

Economy is very good when gentle on the throttle, better than standard as the ecu map is specific to the engine...

[Veero 1]

Bloody hell! GTi6 1 - TBs an management 0. No way one earth I could even consider that anytime soon.

[Batfink 201]

its worth it though. The mid range torque is significantly boosted and the sound is divine

[Galifrey 1]

Can get hayabusa throttle bodies for around £100-150 second hand ecu around £4-500, or new Omex for £600, so doesnt have to be a criminal cost. A lot less if you go megasquirt.

 

Get a manifold and fuel rail fabricated along with a few other bits and £850 odd could see you up and running.

 

If you buy new Jenveys it will of course be much more expensive

Edited October 1, 2009 by Porsche911r101

[DrSarty 90 1 Cars]

I think you've already decided Tris. You want a GTI6.

 

As I always have said: all attitude is a result of experience, and your experience of your Mi is leading you to suspect the grass is greener with a GTI6.

 

You can add an XU10 baffled sump and spacer to your Mi to cope with this potential oil surge issue.

 

Yes ITBs and aftermarket ECUs (plus mapping) are expensive, but it IS worth it, and I get 32-25mpg off a 2.2 on them. You can keep them and transfer them, and the engine performs so much better.

 

I agree that you should sort out the loom and TPS issue. You should then add the oil system items, including the extended pickup. Budget and ease-of-work-wise that is the best solution.

 

But if you want a GTI6 in there then go for it, but be mindful that it too will need a rebuild and that they too have issues such as valve heads breaking off. You can only aim off for that by spending more on the rebuild.

[Miles 331 1 Cars]

Been talking about this a fair bit and to be blunt as always, The amount of U/S GTI6 engine's I get border's on being silly so I would never buy one without it being in a full running car and seen by yourself so it's either £50.00 for a engine out of the car or £600 for a 306 with the engine in and running, You can sell most of the bit's and get some money back too

 

Mi's I never really had too many problems with really in comparission.

[Baz 421]

If you buy new Jenveys it will of course be much more expensive

 

But hugely easier, and arguably much better/applicable.

[Galifrey 1]

But hugely easier, and arguably much better/applicable.

 

 

Easier for sure, but I could not justify MUCH better, there are 1000bhp engines out there using Hayabusa throttle bodies (turbocharged).

[Matt Holley 11]

Been talking about this a fair bit and to be blunt as always, The amount of U/S GTI6 engine's I get border's on being silly so I would never buy one without it being in a full running car and seen by yourself so it's either £50.00 for a engine out of the car or £600 for a 306 with the engine in and running, You can sell most of the bit's and get some money back too

 

Mi's I never really had too many problems with really in comparission.

 

Very true, my first was bought out of a car id seen running, driven etc, second was from a known sorce not seen running and turns out to be a badun, it was being rebuilt anyway but not really the point, maybe the 405 mi16 and bx wern't owned by many ''enthusiasts'' so didnt get bodged along?

 

I would go gti6 every time, had an mi16 for a bit and didnt really like it, but finding a good gti6 engine gets harder all the time.

[James_R 3]

I never had surge issues with the Mi's I had in before with an eggbox in the tin sump, that was combe, anglesea, various ring trips, all seems like forum BS to me this surge thing, ohh a high milage engine knocks a big end, must be surge (nothing to do with the already knackered shells) I knocked a shell out an 8v a few weeks ago, no surge just bad luck. Maybe it's like a fashion statement or something.

 

Mi's are still good engine, that as long as it's not 100k+ ragged example (s16's don't count)

 

Just deniggle and enjoy the Mi will be much less hassle than a 6 conversion and cost!

[DrSarty 90 1 Cars]

deniggle

 

Now I like that!!!

[James_R 3]

did I miss a hyphen?

[Alastairh 47]

that as long as it's not 100k+ ragged example (s16's don't count)

 

Isn't that the truth! My brothers old one had done 188K and given grief on a daily basis and still produced good power before it threw its dummy

Edited October 5, 2009 by Alastairh