Getting More Out Of An Mi16...

[Veero 1]

I am constantly in awe of the things you guys post up on here, mainly the things you do to modify engines and I consider myself lucky I have got a fairly (touch wood) reliable Mi16 which I am well chuffed to have got running myself mainly after getting inspiration from here. I won't even pretend to understand all the ins and outs about these engines but I have a couple of questions that searching on here has only confused me a bit more. Firstly though I am not after a monster output or expecting miracles, but would be very keen to squeeze a few more horses from the engine in my 205.

 

The spec is currently a fully standard 1.9 Mi16 running on standard 3 row management. It's using a reangled PRD manifold and a standard 205 centre section and magnex backbox. I haven't had it RR'd but would hope it's at least vaguely near what it should be. It certainly feels healthy and has given plenty of more powerful cars a run for their money so far. I am soon to be fitting a GTi-6 inlet manifold and TB to counter the problem of the knackered Mi16 TB linkages causing high starting revs and poor idle. A mate has a 1.8 16v xu7? engine in a 306 and fitting GTi-6 manifolds made a hell of a difference, coupled with a 205 1.6 GTi box gave me a damn good run for my money with an engine I thought was only around 125 brake. Would the GTi6 manifold make a noticeable difference to an Mi16?

 

Also is a cost effective method of getting a few more horses fitting an inlet cam (nothing too lairy) to an otherwise standard engine? Can this be done without remapping or otherwise changing the management?

 

I'm not just after getting a higher number for the output of the engine but perhaps changing the delivery slightly. I always thought the power suddenly comes in about 3-3.5k screams for a bit and runs out of puff towards the limiter. Actually not totally sure on that, need to drive it again really, after all it has been sat for 10 months SORNd.

 

So that's it really, is an inlet cam a good way of improving the characteristics of a standard engine or are there better more effective ways for around the same sort of investment?

 

Thanks

Veero

[James_m 0]

TBH, probably not want you want to hear, but i would spend my money on something more worthwhile.

 

I can only comment on my own mods, which is only an inlet cam, but starting again i would'nt bother.

Whilst there might be a small gain in top end power (still no where near 170bhp for sure) and it probably is ever so slightly quicker running to rev limiter every gear, it feels to have dropped a fair bit of mid range, and does'nt seem to wheelspin as much as before indicating it really is now lacking something compared to running with the original cam

It does make a slightly better noise, but it was hardly worth the hassle of taking replacing the old cam and messing around with timing belts etc and overall im not sure its actually gained overall performance from the mod.

But, my Mi16 does seem to be a slow one in general and perhaps not the best example to take comparisons from.

 

I am very interested to see what that inlet manifold does to your car!

Edited September 2, 2008 by James_m

[taylorspug 7]

Im not being funny here, so please dont take it in that way, but a 1.8 306 should not in any way give a MI 205 a run for its money. A 306 GTI6 can make a pretty good job of staying there or thereabouts, but its quite hard to hide the extra few hundred kilos of weight when the road opens up. So it may be worth getting it on a good rolling road first to see whats what before starting any upgrades.

 

The GTI6 exhaust manifold is alot of work to fit to an MI head, pretty much needs the mounting flange cutting off and starting again. For the upgrades you are planning, the MI manifold will do just fine.

[Veero 1]

Thanks for the input guys, it's not a case of what I want to hear I am genuinely after opinions on what is a good solid way to improve the engine and what isn't. As for the cam its a case of a reasonably simple fitment and off you go, whereas some other things will require complete engine dismantling which at this stage I can't be arsed with or really afford.

 

Not really wanting to change the manifolds either, I had a 4-2-1 which was supposedly specifically designed to fit the Mi16 engine in a 205 but it was a country mile out, fouling the bulkhead before the top row of bolts had properly tightened, hence running the PRD angled manifold. The QEP plate I had just seemed to blow whereas the PRD manifold doesn't.

 

The 306 in question was a stripped interior one on slammed suspension. My 205 has full interior and was on standard suspension at the time. To be honest he was probably driving like a bit of a tit but the 306 went round corners like it was on rail and my saggy old suspension at the time was feeling a bit sloppy, and I didn't know those roads praticularly well. Never had a drag race as such but with the 1.6 205 box on it felt bloody fast, much faster than it should have done. Who knows maybe on track it would be a different story...

 

I'm tempted to leave the Mi manifold on for now actually and get it MOT'd as is then get a RR session just to see what it's putting out then change the manifold to see what the actual difference is. On that note anyone know any RR garages in or around Stroud?

[taylorspug 7]

Ive found the ssame as you with those 'special' 4-2-1s aswell, including where someone has seen it wont fit and just hit it until it does, bending the pipes... Tbh i doubt you will see any difference just changing the manifold on its own, the std one flows more than good enough.

 

Ah ok i thought you were referring to a more straight line thing. Id still get it on some rollers before you start, at least if nothing else you can go back to the same place once you have changed a few things and see the fruits of your labour.

[Alan_M 66 1 Cars]

Thanks for the input guys, it's not a case of what I want to hear I am genuinely after opinions on what is a good solid way to improve the engine and what isn't. As for the cam its a case of a reasonably simple fitment and off you go, whereas some other things will require complete engine dismantling which at this stage I can't be arsed with or really afford.

 

Not really wanting to change the manifolds either, I had a 4-2-1 which was supposedly specifically designed to fit the Mi16 engine in a 205 but it was a country mile out, fouling the bulkhead before the top row of bolts had properly tightened, hence running the PRD angled manifold. The QEP plate I had just seemed to blow whereas the PRD manifold doesn't.

 

The 306 in question was a stripped interior one on slammed suspension. My 205 has full interior and was on standard suspension at the time. To be honest he was probably driving like a bit of a tit but the 306 went round corners like it was on rail and my saggy old suspension at the time was feeling a bit sloppy, and I didn't know those roads praticularly well. Never had a drag race as such but with the 1.6 205 box on it felt bloody fast, much faster than it should have done. Who knows maybe on track it would be a different story...

 

I'm tempted to leave the Mi manifold on for now actually and get it MOT'd as is then get a RR session just to see what it's putting out then change the manifold to see what the actual difference is. On that note anyone know any RR garages in or around Stroud?

 

My 4-2-1 manifold bought from Miles new fitted perfectly, although it was a pain in the arse to fit as you have to seperate the thing into 3 parts, and pass each one at a time behind the engine. Coupled with the matching Maniflow centre and backbox (2.5" throughout), it certainly made a difference to the cam'd Mi16 (Only Kent regrinds). Round the Ring, Feb in his '07 Subaru Impreza Wagon WRX could'nt catch me on the straights.

 

What gearbox are you running? Also, is there anyway the timing could be out by a tooth? When mine slipped a tooth, it felt very flat and not quick at all.

 

The GTi6 inlet sounds like a plan as the Mi16 TB's are 99% screwed by now, and with aftermarket management you could also bin the AFM. What I plan to do.

 

As for known mods, PeterT's selection of mods appear to work with a few on here happy customers. The inlet cam seems to be very popular.

[welshpug 1,655]

On that note anyone know any RR garages in or around Stroud?

 

Powerstation just outside Tewkesbury, PSOOC are visiting in a month or two.

[Banjo 1]

GTI6 time?

[boombang 2]

Couple of things I did on my old Mi were:

 

1. Skimmed head an amount determined by my engine builder. Raised the compression enough to again make the engine feel a bit more lively. It was never going to tear up tarmac, and still had the torque drop between 3.5k and 4.5k RPM like standard, but gave a minor power increase across the rev range.

 

2. VW Golf throttle body. Has a small opening first butterfly with a larger one on larger throttle openings. Surface area slightly more than standard and made the engine feel a lot revvier. It was also much nicer to drive as can distinctly feel when you get to open the second butterfly - meant round town was just on the smaller one, which IMHO led to quicker pickup and definately better fuel economy.

 

3. Short ratio box with Mi16 final driver and Quaife. Helped put the power down so much better, and in a straight line to the limiter in 5th would keep up with the last shape BMW M3 (where they then left me for dead).

 

 

The first two are very minor things, but gave a proven 170+ BHP on a few rolling roads. Made engine pickup a lot quicker and the car felt a lot faster in general. The power curve rose at a constant 45 degrees from 4.5k RPM to the redline (IIRC 7.1k or so). Unfortunately you are stuck with the standard limiter unless you look at 4x4 management which again IIRC lets it rev to 7.4k, probably not enough to really reap the rewards massively but might unleash a few more BHP top end and still be safe on hydraulic tappets.

 

To me the gearbox choice on Mi16 engined cars can make all the difference. You've not said (from what I can see) what box you have, but wine was at first on a 1.9 box. IMHO this doesn't suit the 1.9 Mi at all, and feels slower than an 8valve with the same box. The Mi16 box as standard is much better though, and on a road car I would recommend it. The 306 xsi box has similar ratios too so worth looking out for.

[gti_al 1]

I found fitting the inlet cam livened things up significantly. It seems to pull through the midrange quicker, and it gets to the limiter faster in the higher gears. For what peter charges i think it is definately worth doing, and i would imagine that the chip to match it would help too. I haven't got around to that yet...

 

What is involved with fitting a vw throttle body? I discovered that mine is not closing a while back, but haven't got around to doing anything about it yet. That sounds better than fitting an old mi16 one again

Edited September 4, 2008 by gti_al

[dave_gti 0]

this topic is upsetting. I spent loads on my mi16, got it RR'd and set up, and its apperently 179 bhp, on mi16 box and quaiffe, and omg its slow i dunno whats up with it and im fed up with it for now.

[VisaGTi16v 1]

Throttle cable slipped/etc? heh, sounds silly but it can happen and you end up not getting full throttle!

[kyepan 291]

So that's it really, is an inlet cam a good way of improving the characteristics of a standard engine or are there better more effective ways for around the same sort of investment?

 

Thanks

Veero

When you say a bit more it's really important to understand what you mean, because i always feel thats a bit more everywhere.. Most of the cheap things just move the power up the rev range and make the car less fun to drive down the bottom where we usually bumble around.

 

I really like the way Boombang described the VW throttle body though it sounds like it makes the engine Nicer to drive..

 

If you spend over 400 on anything you might as well have got yourself a GTI-6 engine, they have a more torque and from what i have read respond very well to a mild cams. (Not wanting to contradict myself about moving power) or a turbo 8v same ish price, accessible power and bags of torque

A very cheap way to give you a touch more is a peter t chip, it moves the rev limiter up a bit, accessing the other 4-600 revs that are hiding and gives a very mild increase across the range. I've got one coming with his stage one inlet cam, i'll let people know the results when it goes in.

 

Sat down the other day and did some figures because like you I wanted more, here is what I came up with.

 

£150 for a peter t inlet cam and #4 pulley Inc postage, parts only, perhaps 15bhp gain if your lucky. £10 per bhp

£2000 for throttle bodies, mapping, ECU and inlet cam fitted, 35bhp gain ish £57 per bhp

£6700 for an uber engine built by someone else inc all of the above, 75bhp ish gain , £90 per bhp.

 

So... you can clearly see the diminishing returns.

 

I went the other route, brakes, suspension, a diff... it's still not ready as the rear is too soft and has lost it's neutral feel, all in all i would leave it alone, unless your refreshing stuff with standard parts.

[boombang 2]

What is involved with fitting a vw throttle body? I discovered that mine is not closing a while back, but haven't got around to doing anything about it yet. That sounds better than fitting an old mi16 one again

 

Fits straight on, same bolt pattern and basic shape.

 

Only issues you may have are with the TPS. Have seen three different configurations on there. One was plug and play, another (mine) required 2 wires swapping over to give correct signal, and a third had a different TPS which was mounted the other way up.

 

Can't remember exactly but don't think it was a straight swap to put the Mi TPS on there, but get the right throttle body and it's plug and play.

 

Sorry though, I can't remember which was the right one!

[VisaGTi16v 1]

You have to open up the inlet manifold though as the hole is smaller than the vw body, theres a article on the main web site I believe

 

Here

Edited September 5, 2008 by VisaGTi16v

[boombang 2]

You have to open up the inlet manifold though as the hole is smaller than the vw body, theres a article on the main web site I believe

 

Here

 

Completely correct! Forgot about that. Sorry if what I wrote was misleading, haven't done that to an Mi for a few years now.

 

Also every VR6 throttle body I have seen does not look like that. The one's I used were off 1.8 8valve Gti lumps.

Edited September 5, 2008 by boombang

[Veero 1]

Thanks for the responses. Alan, I'm expert at fitting those 4-2-1 manifolds, got it down to a fine art only to find the bloody thing wouldn't fit. Swapping the exhaust back over in the rain as I needed the car for work was not fun.

 

The timing is spot on, I had the engine out a while back for resealing the sump (which failed) and fitting the PRD manifold so while it was off I checked the timing. Nothing has suddenly changed so I assumed it hasn't skipped a tooth. I'm running the Mi16 (from a BX) gearbox that came with the engine. No gripes about the ratios, certainly nice having the longer 5th than the 1.6 box for motorway speeds.

 

Welshpug, nice one, may have to quickly sign up to PSOOC and get the 205 along for that one.

 

Banjo, ruling out a GTi6 at this stage after all the money I have spent on this Mi16.

 

Boombang, I liked the sound of the Golf/Audi TB, but the Mk2 Golf ones are not far off the same age as the Mi ones, I saw a couple in person and they looked pretty much as knackered as my Mi TB. I did find a good condition one but they wanted more for it than I got the entire GTi6 manifold, TB, fuel rail and I would still have to take the manifold off to dremel it to take the new TB anyway. The car is destined to be only used as a fun car rather than getting anywhere long distance so a short ratio b ox with the Mi FD might be a plan later on. For now though I do like the Mi box as it doesn't mean it's not a total pain going anywhere far away.

 

Al, maybe that was what I was hoping someone would say. So its about £150 to get the cam reground and delivered back to me in the UK, how much all in for the chip to increase rev range?

 

Kyepan, some interesting figures and yes the law of diminishing returns. TBs are out of the question at the moment as is an uber engine. £10 per HP doesn't sound so bad. I've already sorted the front end for suspension and brakes, just waiting to see if it's possible to sort out this 306 24mm ARB to fit the 205 rear axle then the back end will be relatively sorted too.

[kyepan 291]

Kyepan, some interesting figures and yes the law of diminishing returns. TBs are out of the question at the moment as is an uber engine. £10 per HP doesn't sound so bad. I've already sorted the front end for suspension and brakes, just waiting to see if it's possible to sort out this 306 24mm ARB to fit the 205 rear axle then the back end will be relatively sorted too.

 

 

yep i've got a 24mm arb in a standard 205 beam, it corners flatter you can get the power down earlier and it's turn in is sharper.. much sharper, and its really easy to do, well worth it... It won't get you that neutral balance you might be looking for but its a whole lot better.

 

PM petert, I can't remember what he sold his for me, because it was all rolled in with a bunch of other stuff including an inlet cam..

 

it should be on its way back some time next week!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[dave_gti 0]

Throttle cable slipped/etc? heh, sounds silly but it can happen and you end up not getting full throttle!

 

 

Sounds Possible, it something i havent checked, i didnt bother becaust my emissions were everywhere last mot, and he said it wasn't set up properly at all. The CO Was VERY low and the HC was high

[Rom 0]

Interesting topic

 

Ive never got round to havign mine on the RR. It certainly feels quick, but ive never been in another MI so who knows! Veero if what we were talking about pans out, we can do a little co pilot test or something

 

Im on my second TB since i rebuilt my engine. And although its clearly better, im not 100% on it. Ive seen the VAG conversion, but not took the plunge yet.

Whats involved with the Gti 6 inlet and TB ? Im guessing someone has done this before ?

 

Power isnt something i chase as a rule. I prefer to spend the money on brakes, suspension etc. Although it wont increase the power, it will improve the way the car can be driven and responds. A decent set of brakes can mean later braking, so a higher overall speed, than say 10 bhp might give.

But it seems your doing all that stuff already.

[Veero 1]

Yeah definitely mate, just sent you a PM actually.

 

Yep done the brakes and on the way with the suspension already, I agree not really a power chaser myself but just after a little more 'pep' I guess.

 

I think the GTi inlet is actually fairly straightforward, picking up thegaskets tomorrow and getting all my spare air hoses from my folks on Sunday so should be able to get it on next week with any luck.

 

Cheers

Veero

[Jon_Bmw 13]

Yeah it is an interesting topic.

 

I think its safe to say 200bhp is what a lot of 205 owners would want to get out of their mi16, me included. Its a nice round figure that wouldn't cause it to have too much power for the chassis, but enough to make it a weapon.

 

I'm relatively new to 205's and mi16's but have a bit of experience spannering etc. We took our 205 to a reputable rolling road on Saturday and it produced 163bhp at 7050 ish rpm. I'll post the graph when I get back to my other home address.

 

It's funny, I have never been in another 205 mi16, but this one always struck me as having good linear power from 4000rpm onwards, but being a bit flat below that. I mean flatter than a 1.9 16v engine should be in a 205.

 

Spec is:

 

Mi16 on 2 row management.

Normal mi16 manifold with custom 2.75/3 inch exhaust. Very loud and annoying.

Small cone filter.

 

So pretty standard really. Annoying as I write this I don't have the graph with me as it would make explaining this easier. I think our one could do with a 7500 rpm rev limit, I don't think there is alot more power, if any, to gain BUT when changing up a gear it'll be in the power band quicker if not instantly. The graph atm represents, not suprisingly, exactly how it drives on the road. You really need to cain the bollocks off it, which is ok because its a track toy. Due to it not having a high torque figures down in the lower range it has very little wheelspin which is ideal.

 

Basically I want about 190/200bhp to make it a little bit quicker round track down the straights but remain driveable off the limit as I do occasionally use it on road.

 

I'm thinking of changing the timing belt, rollers and tensioner, then chipping it to give a slightly higher rev limit. Not expecting to gain anything in terms of power from that. I don't have thousands to spend on this either, so what should be my next step. Mission impossible?

 

Jon

[pacey205 2]

Does it have the split in the downpipe? I bought a new system not long ago and whilst it was an Arvin and therefore should have had the split it didnt. As the exhaust needed changing ASAP I had to put it on and it was much flatter mid range than before but when it gets to 4k it really pulls.

 

Michael

[kyepan 291]

Yep i'd second the exhaust, when mine is blowing ( which is most of the time) it looses a lot of bottom end and urge. Thankfully dave from maniflow has sorted me out with the bits to stop it, and it's already much much quieter.

[petert 585]

Spec is:

 

Mi16 on 2 row management.

Normal mi16 manifold with custom 2.75/3 inch exhaust. Very loud and annoying.

Small cone filter.

 

The exhaust is way too big for the engine spec. I'd drop down to 2.25", or 2.5" max. if you think you're going to make 220hp in the future. I'd just change the inlet cam and the rev limit. That will only net around 175-180hp, but worth the effort.