AlanM

I run an aftermarket quad throttle EFI system using wasted spark on a twin coil set up, and have experimented on the dyno with plug gaps on a fairly modified engine. In my case at least, with a 121 head, there is no increase in power beyond 36 thou, going up to 44 thou with no misfire, but no Hp gain. I use NGK Iridium single earth electrode plugs. I think you could safely run 30 thou with your set up.

Accelerator pump diaphragm probably from a downdraft Weber, as stated above.

On 6/26/2017 at 0:56 PM, Sharktrainer said:

I have mounted a dual sidedraft setup and found that there is no air bypass adjustment. Not sure how old they are but have brass floats. One side sucking 7 the other only 3 via my syncrometer. Don't know what to do at this point. 

Do you mean that one carb has more flow on one throat than the other, or do you mean than one sucks at 3 and one carb sucks at 7 on both its throats.  If the latter is the case you will only have to adjust the mechanism that connects onto the arms to even up the flow at idle.  I would go with the 125 mains and 200 airs at this stage with the 32mm chokes, and maybe a 50 F8 rather than an idle with such a large corrector hole.

From smallest(richest) to largest idle corrector hole is as listed.

F6, F12, F9, F8, F11, F13, F2, F4, F5, F7, F1, F3

I have a Sachs 228mm M3 clutch cover with an Ireland Eng sprung centre 4 puck type plate, on a lightened flywheel in my M10 making 165 rwhp.  Drives as a standard clutch would.  Maybe it does bite a little harder, but doesn't cause me to stall.  No need for a lot of revs or more than normal amount of slipping on takeoff.

17 hours ago, zinz said:

That be the one... here's the pic, sans rodentia

 

 

So simple, even a two-rock monkey can use it.

 

 

Over 30 years playing with DCOE Webers and I never did buy a synchoniser.  I simply use a 2 Ft piece of garden hose to listen to the suck at the mouth of the trumpet, a bit like a stethoscope. I agree that it is rare that each butterfly is exact, with there being a slight bend in most shafts. I do sometimes check in the setup, the position of the butterflies in regards the progression holes that are under the small brass screws near the front.  I use a piece of thin copper wire down one of the progression holes to work out the butterfly position, or with a torch you may be able to see the edge of the butterfly.  I would go with the jets you currently have as a start.  If your carbs only have two progression holes, I have been able to improve the transition from idles to mains by drilling a third hole with a 30thou number drill.

My current "good" engine runs a 92.5mm bore in an E30 318i block with a 2.3 S14 crank.  It is an engine I bought cheaply, but I would only have gone to 91mm.  Runs 10.6 to 1 with Motec and quad throttle body injection, with 165Hp at 6600 rpm at the wheels on 98 RON pump fuel.  Has a custom thin 40 thou standard type head gasket.  No problems so far, but I have seen bore walls that you could flex with your hand at 92mm in other M10 blocks. Maybe mine was sonically tested OK beforehand.

I would try going to 135 Mains with 185/190 Airs to perhaps solve your woes.  I had a good run with F9s emulsions in my car, but the engine had bigger compression, cam and carbs than yours.  I ran 55 F8 idles with a Schrick 316 that worked OK,  I had 45s with 38mm chokes. As you have stated, 34mm is the largest standard Weber choke for a 40. The 1mm will not make any noticeable difference in your case.  2Litre Alfas ran 32s in 40s, with similar power to your car, and running out of revs wasn't a problem.

A cam sensor I made and used on the M10

I had a similar type of TDC sensor on my M10.  I did find that the position the ECU was seeing moved around a bit with the chain driving the cam, and the distributor running off the skew gear on the cam. This moved so much that at high revs my M4 Motec would bring up a synch fault.  I fixed this by fitting a support boss for the GT101 sensor on the front of the timing case cover, and making up a tooth that bolted to the end of the camshaft eliminating the skew gear, and possible camshaft twist at high rpm because of the large cam and heavy valve springs.

The engine became much more responsive in its tuning after fitting the new type pick up.

Just to add something a little more out there.  Is the cam timing correct? If the cam were 1 tooth advanced it would also have no top end power.  If you pull the tappet cover and bring the engine to no.1 TDC  on compression, with both exhaust and inlet having clearance, then no.4 will be on overlap, meaning both valves will have no clearance and both will be partially depressed a bit under 2mm with a standard cam. If one valve has clearance then the cam timing is out.

If the motor had a big cam fitted it would have been having valve to piston clearance issues if it were out by a tooth. While you are at it, checking the tappet clearances wouldn't be a bad thing to do whilst you have the cover off.

I have built a few modified M10s, one with an E12 head and others using the 121.  As a standard head I think the E12 might flow a little extra, and 121s are usually used as the combustion chamber is smaller so as to get more compression and has more "squish" area to force the mixture toward the centre of the chamber and cause more turbulence giving better combustion. Back in the day my 2L E12 M10 made 130 Hp at the wheels at 7200 on Webers. My latest 121, 4mm  stroked  M10 makes 165 Hp at the wheels at 6700, with quad throttle body Motec injection.  After modification, big valves, porting, custom pistons, I don't think there is much in it.  I have found 121s seem to crack more than others, but now I weld the head and re-drill holes for the water galleries to prevent this.

Not that I am currently using one, but I do like the Shrick 304 for your type of use, but buy some of the better rockers from Ireland or others, as failure often occurs with biggish cams and springs, and high revs. With the injection even the 316 was reasonably streetable.  I currently use an Australian Cam from Tighe Cams, a 521A. You can look up the specs on their site.  I had this in a street/race car for many years on Webers.

Some years ago I was at dyno running a L20 Nissan motor with socks over the ram tubes.  I told the owner that they caused interference to the intake flow for the am tube and reduced Hp.  On a chassis dyno it picked up 10Hp at the wheels with them removed. Ideally you would have your ram tubes housed in an air box with a panel filter at the front of it, where the engine can take in the air from a relatively still air area.  I have found on the M10, it seems the longer the ram tubes the more power and torque are produced.  Do not use the mesh covers as they only stop rocks, and depending on the engine will reduce top end power.

200mm tubes produced the same top end hp just at 5700rpm instead of 6500 over 100 mm tubes.  At 3000 the long tubes were up 12hp, 4000 still up 12, 5000 up 20, 6000 up 8, on a chassis dyno. At that time it was topping out at 151Hp at the wheels on a Dyno Dynamics.  With some more work it now makes 165Hp at 6700 only dropping 3hp by 7200, still with the 200mm ram tubes. Comp ratio is only 10.6 on 98RON, and could be pushed to a little over 11 with some improvements in chamber squish, picking up a little more power.

I would be interested in what the cam grinder specified as the lift ramps may well be different to the original BMW cam necessitating a different clearance. If no info available I would still go with 8 thou inlet 10 thou exhaust.

Are you using DCOE Webers for induction? The rpm point of peak power can be raised by retarding the cam a little. It may be worth seeing where it is currently. A simple check is to put the piston to TDC on overlap and check how much valve lift you have. If the cam is neither advanced or retarded this will be approximately equal and around 2mm or 2.5mm from my failing memory for a 304.

Try disconnecting the tachometer wire from the negative side of the coil. I have had the tachometer short the coil to ground at a particular rpm as it sort of reaches a resonant frequency on a failed input capacitor.

I have IE springs and titanium retainers in my race engine with a very similar cam to a Schrick 316. Certainly no valve float up to 7700 rpm, and the cam doesn't seem to falling apart with excessive pressures. These springs have been fitted for approx 2000 race klms.

 I did have a 316 in my M10, but with some more head mods, the cam (Tighe Cams 521A) and spring/retainer change, and a little more compression, longer ram tubes (from 4" from 8"), multi -hole injectors the engine now makes 165Hp at 6600 at the wheels, up from 150 at 7300, with between 8 and 20 more Hp from 2000 rpm up, on the same dyno in similar weather conditions. The new set up only loses 2 hp from 6600 to 7300. 

I'm not a track guy, but I want to be at some point.

Obviously 02s would be my track car of choice. When I think about it I always think about the quibo being a weak link in the drivetrain. The punishment that little rubber connection suffers can't be good.

What experience and advice do race car owners have?

I have a track/street 2002 that has done approx 3000 klm on the track in the last 5 years on the same Febi brand guibo.  My M10 makes 165 Hp at the wheels.  I think the problems with guibos that people are having is more to do with the set up, than a weakness in the guibo design in itself. A friend with a track 02 with a S14 M3 motor in place has 230 Hp at the wheels, and until recently when he changed to a sequential gearbox was running a standard guibo without problems.

Do you have an E21 diff fitted without using spacers or longer shafts?  The output flange is only held in with a round circlip along the shaft and will pop out if one of the above mods is not done, giving you no drive if you have an open diff.

Happy to chalk it up to the incident above but want to check that I have not missed something else.  Also, does anyone know what the correct bolts sizes are for the guibo.  I am guessing they should all be metric, not a combination of UNF(?) and metric! 

You have High Tensile UNC (Unified National Course) bolts fitted which I guess are 3/8".  Yes you should have 10mm Metric Bolts with a tensile rating of at least 8.8 on the top of it.  10.8s would be better.  I use allen key inhex style bolts that are I think 12.3, with new nyloc nuts fitted. Running 165 Hp at the wheels in a track car, but not having any trouble with guibos. I have some aftermarket German brand guibo in mine.

I have a 318i block M10 out to 92mm with 84mm stroke in a built engine I bought.  I was surprised to find it was out to 92 when I removed the head to try and find some more Hp.  I had thought it was only 90.5 for some reason, and I also think 91.5 is the full limit of our blocks. I saw a 2002 block that had been taken out to 91.5, and after a teardown there was a discolouration on the wall of number 1 cylinder against the water pump.  Seems the wall was so thin that it could be pushed out of shape with your finger. It had a fair bit of blowby on this cylinder.

 I did find some more power though, up from 150 to 165 Hp at the wheels on the same dyno. The bores looked OK.

 

As for location, I am in South Australia, Adelaide, to be exact.

I have the old diff in the shed, and will see if I can find any markings on it for ratio.

I do have a spare speedo, but it is an mph speedo. Not sure if I can legally run one of those these days.

 

I live near Brisbane in Australia.  No problems with running an MPH speedo in a pre '76 car.  Given most 2002s were produced before 1976 you will have no dramas. Just put some small bits of tape showing 60, 80, 100Kph set up via a GPS, and not worry what the numbers the speedo says.

I run a 4.1 diff in a "73 Tii with a 235/5 5speed with 1:1 5th, 205/50/15 tyres, showing about 50MPH when it is doing 38. (80Kph is 60 approx.) I don't know which speedo I have nowadays. 

 

Many of the dynos in Australia are Dyno Dynamics, but usually there is a printout at the bottom of the graph stating the ambient temp, relative humidity and various other settings like Shootout 4, so that a comparison can be made between days to explain differences.  

Looking at the recent Dyno Dynamics run my fairly modded 2258cc ITB Motec M4 M10 ran very closely to yours till 4500 rpm but mine continues to climb to a 165HP peak at 6600 and stays flat to 7200. I only run to 7500.  Mine is a road driven race car compromised more toward race, but is still quite driveable at slow speeds.  For a road engine, yours is well sorted to see 135 at the wheels.

I also had sync errors for many years caused by using an adaption of an old distributor to give the TDC pulse for sequential injection, but with the play in the gear and the slight timing chain movement, it would change the sync position a bit and upset the Motec, and of course the timing. I had 150 at the wheels for many years, but a combination of fixing the sync, bigger 4 sprayer injectors, and actually a smaller cam (was Schrick 316, now Tighe Cams 521A) have it going the best it has been.

I only fixed the sync recently by mounting a GT101 pickup on a boss on the front timing cover in front of the cam, and fitting a manual adjustment on the timing chain.  There is now only a couple of degrees of "quibble" at idle which becomes dead steady above 1500 rpm. 

It sounds like your pressure relief valve in the oil pump is not assembled correctly OR it has some wear and has stuck in the closed position.  You need to remove the pan and pump and inspect it. 

Actually I pulled the pump out and could find nothing wrong, relief spring was the same in thickness and length as another car that the pressure was OK on.  Reinstalled pump same problem.  Replaced pump with a brand new one, still the same.

Thought there may be a cloth jammed in an orifice somewhere, as I had bought it as a used race engine,(S14 head on M10 Block with 77mm billet short stroke crank) but I blew it all though with air so I knew the galleries were clear.  Removed the M3 filter housing that was fitted that allows a cooler to be fitted, and just ran a filter on an 02 housing, still excess pressure.

All up had the pump out 4 times, and still don't know what happens, but an external pressure relief solved the problem, just I don't why there is one.  I have built maybe 30 engines of different makes over the years and have reasonable experience, this just stumped me.  

The engine was run then on the track without problem until the thrust part of the main bearing died, mostly through the use of  very high clamp force on a 7 1/4" aluminium AP Racing clutch. 

Hey Alan, just wondering how you knew that the relief got jammed?

The car is basically a road registered race car and has a 700 KPa VDO oil pressure gauge, which I didn't believe as it was hitting the end.  I then fitted a 1000Kpa gauge (150PSi) which also hit the end at revs, particularly when the 10W40 oil was cold.  I then tested the gauges against a master gauge at work, and were found to be within 40kpa of being correct at the top end.  I ended up "fixing" the problem by fitting an external adjustable pressure regulator in the oil cooler line and ran a relief line back to the sump.  So I fixed the resultant high oil pressure, but still don't know why this engine did this.

Eurotrash asked that I move this posting from Dyno and EFI tuning so as not to get lost.

I dynoed my M10 yesterday after changing many things between when I last tested the car.  Same gearbox, diff ratio, wheels and tyres, but had fitted bigger 440cc  4 hole injectors instead of the single pintle type, changed fuel to 100 RON with10% ethanol, instead of 98 no ethanol, changed camshaft from Shrick 316, to slightly smaller one that lifts the valve a little quicker, new different shape valves, new springs, titanium retainers, different pickup for the cam sensor for sequential injection.

Old sensor was setup using a modified distributor, but it caused wandering of timing because of gear drive of distributor.  Also fitted an externally adjustable camchain tensioner to reduce possibility of chain whip altering cam and pickup position. Now sensor is directly off the front of the cam and timing is much more stable.

Raised comp ratio from 9.8 to 10.6 (from memory) by using custom 40thou thick head gasket instead M3 one, and reduced squish in chamber by 32thou. Could still be reduced by another 22thou, as pistons down bore 22 thou.  I did not build the original engine (bought inexpensively from a friend after only 3 race meetings) and was too lazy to pull the engine completely apart to deck the block 22 thou.

Fitted an electric water pump.  

Originally had 150Hp at 6300 at the wheels, now has 165 at 6600 and only drops 2hp to 7200. Old set up about 5 hpbetter through the range until 5000. Not directly comparable as yesterday had higher humidity and temp.

Hp peak is lowish down the rpm range as the engine is fitted with long 200mm ram tubes.  Tried plug gap at 32thou originally, with dyno operator recommending 44thou as coils have sufficient power. Said I had tried this without success many years ago on same type engine. Lost 5-7 hp through range except equal from 5500 onward. Brought gap back to 35 thou and was same as 32.

Took out Unifilter flat panel air cleaner towards the front of the carbon airbox, and made about 5hp more to 5700, then same as before.  Operator thought that by removing the filter the airbox became effectively larger helping the lower revs though a better resonant frequency suiting ram tubes and extractor lengths.

I could try retarding the cam a little, which should result in more top end Hp at higher revs, but would most likely lose some bottom end, and I really don't like running it past 7500, even with an M3 crank, Carillo rods, and forged pistons in the bottom end. Longevity drops off quickly past this point.

All up a good day.  Motor still healthy, made more power and I got to try a few things. Charged 3hrs dyno and operator time. Think I will leave the motor as it is as gains Vs costs get out of proportion going past this point.

Still quite driveable as still have 75Hp at the wheels at 3000 rpm.

Going to the track Friday and hope to be at least second quicker, with more Hp, bigger brakes, new tyres, but I haven't been on a track for over a year.  Perhaps my money would be better spent on practice, rather than mods.

I dynoed my M10 yesterday after changing many things between when I last tested the car.  Same gearbox, diff ratio, wheels and tyres, but had fitted bigger 440cc  4 hole injectors instead of the single pintle type, changed fuel to 100 RON with10% ethanol, instead of 98 no ethanol, changed camshaft from Shrick 316, to slightly smaller one that lifts the valve a little quicker, new different shape valves, new springs, titanium retainers, different pickup for the cam sensor for sequential injection.

Old sensor was setup using a modified distributor, but it caused wandering of timing because of gear drive of distributor.  Also fitted an externally adjustable camchain tensioner to reduce possibility of chain whip altering cam and pickup position. Now sensor is directly off the front of the cam and timing is much more stable.

Raised comp ratio from 9.8 to 10.6 (from memory) by using custom 40thou thick head gasket instead M3 one, and reduced squish in chamber by 32thou. Could still be reduced by another 22thou, as pistons down bore 22 thou.  I did not build the original engine (bought inexpensively from a friend after only 3 race meetings) and was too lazy to pull the engine completely apart to deck the block 22 thou.

Fitted an electric water pump.  

Originally had 150Hp at 6300 at the wheels, now has 165 at 6600 and only drops 2hp to 7200. Old set up about 5 hp better through the range until 5000. Not directly comparable as yesterday had higher humidity and temp.

Hp peak is lowish down the rpm range as the engine is fitted with long 200mm ram tubes.  Tried plug gap at 32thou originally, with dyno operator recommending 44thou as coils have sufficient power. Said I had tried this without success many years ago on same type engine. Lost 5-7 hp through range except equal from 5500 onward. Brought gap back to 35 thou and was same as 32.

Took out Unifilter flat panel air cleaner towards the front of the carbon airbox, and made about 5hp more to 5700, then same as before.  Operator thought that by removing the filter the airbox became effectively larger helping the lower revs though a better resonant frequency suiting ram tubes and extractor lengths.

I could try retarding the cam a little, which should result in more top end Hp at higher revs, but would most likely lose some bottom end, and I really don't like running it past 7500, even with an M3 crank, Carillo rods, and forged pistons in the bottom end. Longevity drops off quickly past this point.

All up a good day.  Motor still healthy, made more power and I got to try a few things. Charged 3hrs dyno and operator time. Think I will leave the motor as it is as gains Vs costs get out of proportion going past this point.

Still quite driveable as still have 75Hp at the wheels at 3000 rpm.

Going to the track Friday and hope to be at least second quicker, with more Hp, bigger brakes, new tyres, but I haven't been on a track for over a year.  Perhaps my money would be better spent on practice, rather than mods.