[engine_work] Mi16 Stage Rally Car

[brumster 135 1 Cars]

I ummed and ahr'd as to whether the forum really needed yet another "mi16 conversion" log, and have pressed cancel on a number of times, but then I realised this might actually be a good motivational decision on my part!

 

I've had the car since 2001 and over that period it has received numerous upgrades in terms of suspension, transmission, brakes, tyres and interior/electrical trinkets, but the engine has remained a venerable old 1.9 8v lump (albeit a very nice Skip Brown blueprinted ex-challenge engine). Much as the old engine has been a wonderful, reliable workhorse over the years, the rest of the car has evolved to the point where the engine really is short of a few horses out on the events. We tend to sit in the same class as Mk.II Escorts with 2.0 16v ecotecs, vauxhall red tops and Honda S2000 lumps, all making upwards of 240 horses - so you can imagine our pitiful 125+ leaves us behind a fair bit on the straights.

 

I've had a BX mi16 lump sitting on an engine stand for quite some time, and back in May/June I started stripping and rebuilding it.

 

Initially my idea was to go pretty basic, with an emphasis on reliability and driveability rather than outright power, and to keep the costs reasonable. After talking to many competitors running mi16's, particular Andy Corner who runs one in his 205, I settled on the idea of a complete standard (rebuilt) bottom and top end, but run it on throttle bodies and some sort of EMS. 160 or so horses would suffice but the improved driveability of the throttle bodies would be the main benefit, plus an increased rev range over the 8v unit.

 

This was all sort of going to plan until Andy Baker at AB Motorsport (a good friend and major contibutor to the car over the years in terms of work and parts) mentioned a pair of CAT cams and talked me into parting with some more hard-earned so the 283 duration high-lift jobbies (4900528) were ordered and fitted into the newly-refurbed head. The bottom end was rebuilt with the usual ARP bolts, a PTS-style sump baffle kit and a PTS high-pressure oil pump spring, new rings, new bearings, new oil/water pumps, and so on. Some vernier cam wheels aid in the tuning and obviously a new belt and tensioners have gone on there.

 

Induction-wise I've got the usual Jenvey TB's on Longman-sourced (maniflow?) inlet manifold, with some uprated injectors I sourced from this here forum. The fuel tank will be opened up and the pump removed, replaced with a low-pressure FSE pump that will fill a 1.5l swirlpot (yes, I suffer from the inevitable 1/2 tank fuel surge, Dunlop CR311's don't help in this regard!). From there a Sytec (FSE) motorsport high-pressure pump will feed the fuel rail, with an adjustable pressure regulator and return back to the swirl pot.

 

EMS-wise I'm using EFI Technologies. The main reasons for this are (1) Longman and Andy Baker's recommendation and good results with it (2) it's self-learning mapping capability with a lambda sensor means no rolling-road based mapping, but true on-the-road mapping sessions. It's the Euro4 system.

 

Exhausting via a Maniflow 4-2-1 manifold and into one of Andy's Powerflow custom-made systems. If it makes ~185-190 I'll be happy; I rolling roaded the 8v on a rather dodgy rolling road and got a figure for comparison with the new one, so we can at least measure any improvement.

 

So now it starts in earnest. The new engine is built, and last weekend I removed the old 8v.

 

Before the new one goes in I want to clean up the engine bay, tidy away some piping/wiring, and also take the opportunity to fit Saxo/106 electric power steering (pump already sourced).

 

More pics to follow, but for now :-

 

[brumster 135 1 Cars]

Oh, P.S. this could sit under so many subforums I didn't know whether to stick it in general discussion, performance upgrades or here, so by all means move it mod's if you see it under another section better

[philfingers 5]

The big question (unless I over looked it) is what are you doing about the sump. With the exception of one person (i'm talking stage rally cars now, not fast road or track day cars) who was running the std oil pressure gauge (unreliable/ inaccurate at best) everyone I've spoken who haven't dry sumped their engines have run the bearings due to oil control issues. The general consensus seems to be the only sure fire way of maintaining reliability is to dry sump, which is expensive. There loads of information on the oil control issues of Mi16s. I run a 205 (yet to be used, used to run a 309) in road rallies and was considering running an Mi16 I have but decided against it. The only other option with good record (but not proven in rallies AFAIK) is the www.taylor-eng.com modified pickup and Xu10 sump.

Phil

[Sandy 189]

Baffles and solid lifters (with a restrictor) works well.

[brumster 135 1 Cars]

Interesting; investigations made to those in the know showed no concern (for example, Andy Corner ran an mi16 with no dry-drump for quite some time now with no issues). Naturally the sump is baffled, there's a high pressure spring in there and I'll run it to good capacity. sandy, what's the restrictor you mention?

 

I run a very accurate digital SPA oil temperature/pressure guage, with warning light and high/low recall so for now I think I'll pay keen attention to it, particularly on any events with long, sustained high-G corners (MIRA, for example - there's not many) before shelling out on dry sumping/accusumping. I know it's the same old argument "Well, what will an engne rebuild cost you if you have a problem?" but at this point I can't bring myself to shell out on dry sumping...

 

Concerns duly noted, though, and thanks

Edited October 14, 2007 by brumster

[brumster 135 1 Cars]

Darn lack of search engine.... anyone got the flow rates for the standard fuel pump?

[VisaGTi16v 1]

High pressure spring is irrelevant if no oil to pick up. I have sprinted my Visa with its Mi16 for a few years now and as time has gone on its got to the point where its been on slicks for the last 2 years. It has a PTS baffled sump as well. Recently I actually bothered to look at my standard slow oil pressure gauge and noted it moving on the corners and then found out that my stop light wasnt working. So I have fitted in via a t-piece a standalone pressuge sensor rigged up to a light inside and its set to 25psi. My last sprint at Debden, it came on 5 or 6 times at a variety of times. Slow, fast, left, right handers and under braking.

 

One part of me things ffs why did I fit it, its lasted 5 years should have just carried on using it as it was. The other sensible part now knows that I have been seriously riding my luck for years. I cant see how it can regulary go under 25psi and not eventually pop!

 

I have started looking into it on here and elsewhere on the web. I dont think an accusump is of any use. There were figures from a test done by Rob Thomson showing how the pressure can drop from 90-45 psi in well under a second due to how much oil the head needs, an accusump just cant keep up for a corner of any decent length plus the Brent brothers who race in one of the SE series have fitted one to try and solve their constant retirements but it hasnt helped.

 

The main problem is actually how much oil the head needs and lack of drainage. It apparently has a lot of empty space which the GTi6 head doesnt. Some people were on about filling it with liquid metal but no conclusions. Also I recall reading something about there are two drain holes but one is blanked off in the Mi16, both are open in the GTi6. I am probably taking a year off from sprinting next year but will be looking into this further with head draining being the concentrated area.

 

However for as many reported problems, there are loads of people using them and are fine, been 5 years for me, James Lumley rallies one with well over 200bhp with an accusump and is fine afaik. See how it goes and if you find it flagging up low pressure then look into the drainage. Other helpful solution is an XU10 sump I believe with modified pickup as it allows you to run more oil although the sump will be lower so bear that in mind

 

Here is my video from the sprint at Debden. You can see the warning light glowing as a reflection in the top of the windscreen just under the black tab where the rear view mirror used to go. Ignore the fluffed gear change half way through though heh, lost loads of time but still just managed to get the class win!

[VisaGTi16v 1]

Although a number of the times it came on there were slow, very tight corners with it at low revs in 2nd so the pressure would have been lower. The day before at Lydden it only came on once at the top hairpin so maybe I worry to much! That was a busy weekend, I drive to events as well!

[gti_al 1]

Here is my video from the sprint at Debden. You can see the warning light glowing as a reflection in the top of the windscreen just under the black tab where the rear view mirror used to go. Ignore the fluffed gear change half way through though heh, lost loads of time but still just managed to get the class win!

 

Jezus! I wish i hadn't watched that... the light spends a lot of time on!

[VisaGTi16v 1]

Yes!

 

but then ive been there 4 times over the last 2 years and its a 200 mile round trip on the road as well and its still running.....

 

There is always the chance it wasnt preset correctly to 25psi when I bought it. Its adjustable by an allen key and I can only compare it to my gauge and you know what PSA gauges are like for accuracy! On hot idle though when the gauge is showing about 2, the light will be on so it sounds in the right ball park (low pressure on hot idle is fine)

Edited October 19, 2007 by VisaGTi16v

[petert 554]

I have my light set to 25psi. It only ever comes on at idle (1200 rpm) when hot.

[pugman211 0]

isn't 25 psi a bit high???? Only reason why i ask, is i'm sure i've read the standard oil warning light comes on at 0.8 Bar which works out to roughly 12 psi.

 

If you have set yours to 25 psi, then thats nearly 2 bar of pressure??? Maybe thats why the light is coming on so much???

[gti_al 1]

I have my light set to 25psi. It only ever comes on at idle (1200 rpm) when hot.

 

Is that because your pickup mods raise pressure, even at idle?

 

I looked into my situation anyway, and think i established that i need a deeper sump to accomodate the extended pickup. Are there any worthwhile improvements that can be made with the baffled mi16 sump i currently have?

[VisaGTi16v 1]

pugman: 25psi is low. The standard stop light set up is of no use even if it came on instantly, 12psi bar is to low. You really should have 40+ at 4k or something, more at higher revs. Peter T's mod doesnt raise pressure it just helps maintain it.

 

As I think the search function is still broken, could you give a brief overview Peter. I seem to recall it was an Xu10 sump (off a GTi6?) which has its own single vertical baffle possibly with a trapdoor in the middle. You need the sump spacer as well and then have to extend the pickup? Where is the pickup, on the gear box side of the sump? Can that be extended to be in the middle? Could I reuse my PTS baffle or not as there would be big gap under neath it due to the lower xu10 sump (presuming of course I cut out the standard single baffle in it), so it would be useless?

 

cheers

Edited October 20, 2007 by VisaGTi16v

[brumster 135 1 Cars]

Sorry for the lack of posting - the move to this subforum through me a bit

 

The old 8v briefly showed low pressure (<25psi) on the new SPA gauge so, as has been said, I wouldn't want it any lower so that I can get good forewarning. The light comes on and I can look at the gauge and read it pretty quickly for an accurate figure - if it's briefly dipped below but I'm sitting idling I know not to worry too much, but if it reads zero I know to reach for the ignition switch !

 

I'll start saving up for the dry dump kit then

 

Continuing with the notes :-

 

Spent the weekend building up the 1.5l swirl pot into a catch tank for the rear of the car, planning how the two pumps (low and high-pressure) will fit in and how to route all the piping, and what Goodrich fittings to order from Merlin. Have also measured up for the power steering hoses, as I need to get one made up to go from the Saxo pump to the rack, and a new low-pressure fitting for the one end of the other hose. The 70A relay came today for switching the pump, too. Hopefully all the fittings will come this week, plus the hose, and I can get the catch tank and gubbins in the back, and the power steering rigged up loosely if nothing more.

[James_R 3]

I still think Accusumps are of some value, having read back through Rob T's and Anthoni's posts about it all, they seem to have missed the point of the Accusump, which is you set the air pressure once it's charged to the desires release pressure. They had it sitting at 90psi then if the engine dips below 90spi it will feed the engine till they equalise, if you set it down at 30psi then it won't release the oil till the engine supplies below 30psi granted it's not solving the surge, but if it's for a second-3 then it shoudl hold the pressure at a suitable level to stop the engine bottoming pressure out.

 

Anyways I'm planning to run with one, for the money it's a good safety optin if it saves the engine only once. the placement of the pump on the dry set up on a rally car looks scary enough.

 

I run the stop light at 20psi and it dips on if the engine's hot and the revs drop below 800rpm (when it hunts) I also chose a mechanical gauge over a digital job as you'll spot a needle moving about and not so much numbers changing unless you actually look at the display.

 

Anywho, good luck with the build, looks neat

[Rob Thomson 6]

I still think Accusumps are of some value, having read back through Rob T's and Anthoni's posts about it all, they seem to have missed the point of the Accusump, which is you set the air pressure once it's charged to the desires release pressure.

Er, no you don't.

 

The air pressure is the surcharge that pushes against the reverse (to the oil) side of the piston. The surcharge pressure is the pressure at which the Accusump starts filling, and conversely the pressure at which the last oil is pumped back into the engine on discharge. The maximum pressure (i.e. 90psi) is the engine oil pressure - simply the engine charges the Accusump until the air pressure is equal to the engine oil pressure.

 

As soon as the engine oil pressure drops (for whatever reason, be it surge or just returning to idle) the Accusump will discharge until the pressures equalise again. However, due to Boyle's Law (I think) the pressure drops very quickly as that oil is discharged. If you have a six pint Accusump only a pint or so of that oil is of any use, because the remaining ~5 pints will be discharged at a pressure that's too low to be any protection to the engine. Given the oil flow in an Mi16 (~25 litres/minute), that pint doesn't give you much protection.

 

There are other things too. After surge (or whatever) when the oil flow is trying to restore its oil pressure, the reverse is true and the first five pints or so will go straight into the Accusump cos it offers very little resistance until it fills up and the air gets pressurised to a useful amount. So the bearings etc are starved as the oil is used to fill the Accusump.

 

Checking the oil level... becomes a complete bastard. You have to ensure that the Accusump is full before adjusting the oil level in the sump so you have to shut the valve to isolate the Accusump when the oil pressure is at it's maximum. Otherwise there's an artificially large amount of oil in the sump. From what I've heard, good old Sean f*cked his new DES-Developments engine because he thought his sump was full, when in fact as soon as he started his engine and drove the car in anger all that oil got pumped straight into the Accusump. Result: One very expensive pile of scrap metal. Never mind, eh?

 

I could go on and on.

 

You see what I'm getting at? It sounds great in principle but there are several perfectly sensible reasons why it isn't a particularly effective solution, and is a nightmare to manage. And all these things were shown to be true when tested on Antoni's car. Sure, if it's managed properly it provides a small amount of protection that might be enough to prolong the life of an engine, but it's by no means a solution to the Mi's surge problem.

 

And another thing... I've never, ever seen one on a rally car.

[JamesLumley 4]

Fascinating reading and all of the stuff Rob says may well be true but the fact is that I used to wreck Mi16 engines every couple of events before I fitted an accusump and having now rallied with it for the last couple of years - not once have I had any bearing issues! (runs off to touch a piece of wood).

 

I now use it successfully with my Longman's btcc engine - on Richard's own recommendation and again still no problems. He swears by them over a dry sump setup unless you need the slight gain in hp or need to run a lower mounted engine.

 

My car runs 8 inch wide slicks on widetrack suspension - purely on tarmac therefore generating some serious cornering forces - believe me when I say ACCUSUMPS WORK!

[VisaGTi16v 1]

I have no knowledge of them really other than what ive read on here. Could it be that you are using yours in a different way to the one Rob tested? Set up with different pressures, piping and all that? A brief run down or comments on his post could be useful ta

[brumster 135 1 Cars]

Is there any guidance to the maximum length of hose between the accusump and engine? What diameter hose is advised? Just wondering where to put it if I do fit one. They T into the pressure sensor point on the front of the block, I assume, so fairly easy to fit?

 

Progress really slow as have been waiting on bits for weeks now. Engine might just go in this weekend if everything turns up tomorrow but I'm somehow doubting it, so will probably get some of the wiring out of the way

[brumster 135 1 Cars]

Well this weekend we got the new engine in place. I went back to my old pedal box but had it refurbished and fitted with some appropriate AP master cylinders. This clears the head but also gets round the problem of where to run the vacuum in for the old servo, if it was kept. The bodies are just on there loose to check the clearance (the fuel rail just sneaks in under the bonnet line) and there's still plenty of wiring and plumbing to do.

 

 

In the back has gone the catch tank with 1.5L swirl pot and the high and low pressure fuel pumps, and of course we removed the old pump out of the tank and fitted just a pickup into it. The high pressure pump is an FSE item while the low pressure is just a cheapy FSE/Facet jobbie.

 

 

Some wiring up of the pumps to do, and plumbing it all back to the front. Looking forward to starting it this weekend, if not before

[brumster 135 1 Cars]

Well the weekend we got all the high pressure lines finished up in the engine bay with a mind to starting it. This also meant the Longman sourced maniflow exhaust manifold had to go on. A tip : this can be fitted with the engine in situ, by loosening the lower engine steady to allow some movement, then splitting the manifold into it's two pieces. Put the outer port piece on first, sliding it down into the tunnel. The second piece then slides in alongside it, with a major twist upside down first to get it in, then spin it upright as it's sliding in. It can be done

 

Anyway, the alternator went on and all the wiring got plumbed up too. Testing the low pressure pump first and no leaks between there and the swirl pot, so we moved onto the high pressure circuit. Fsssssh! Sytec hose finishers are official s*it . Actually, it's the jubilee clamps in them that are s*ite; they cross before clamping up to any decent pressure. I swapped these out for some better ones and we were all safe again .

 

So we oiled up last night, plugs out and go the thing up to oil pressure, so that's a weight off my mind. We gave a quick attempt at starting but with no joy and a dieing battery, I called it a night and I'll re-attempt that tonight once we can sit and look at things a bit better. Probably something silly like a wire missed off the ECU or something...

[brumster 135 1 Cars]

Well, the saga continues. A re-attempt with fresh battery still wouldn't start it, and the lack of smell of fuel from the TB's didn't sound promising. Off came one of the HT leads where it soon became apparent that there was no spark either (well, actually, an occasional spark on start or finish of the crank cycle, but certainly not during). Re-checked all the wiring to the ECU, including the +ve's, but that was all fine. This was when I had the idea of quickly rigging up the laptop to the Euro1 and seeing what the diagnostics screen reckoned was going on. No joy here, and a later call to Ole Buhl made me realise what a numpty I was because I needed a CAN interface first, rather than a straight serial port connection from ECU to PC !

 

So not started yet. Myself and Andy suspect the unit hasn't been programmed/mapped for the right flywheel pattern but not being able to get into it, I can't really check, so Ole are going to review their records and see what they believe it's been programmed to. Hopefully that's all it is.

 

Still, plenty of other little jobs to finish tidying in the engine bay and cockpit, so it's on with that this weekend...

[Green Machine 3]

for example, Andy Corner ran an mi16 with no dry-drump for quite some time now with no issues

 

Andy used to get through loads of engines in a season, he just kept it quiet.

[brumster 135 1 Cars]

Ah. In that case, "bollocks"

 

Spent today doing all the little 'nadgery' jobs, like the throttle cable, making a bracket for the coil pack and power steering fuse/relay, re-fitting the rad and hoses, removing the rear brake valve now it's on a pedal box, and so forth. There's no starting the car so the ECU is going back to Longman to check it's been programmed for the right flywheel pattern (our main suspicion on why it won't start). It's all these horrid little jobs that takes the time, unfortunately, soldering up all the wiring and so forth

 

Oh well, get there in the end! Time to book it in for the exhaust fabrication, I think...