what compression ratio does a standard eta block with a 325i 885 head make? and what are the expected torque/power figures for such a build?
thanks
eta engine
Moderator: martauto
bump. im sure it probably says on the wiki, however the link isnt working
http://www.e30zone.net/e30zonewiki/inde ... ding_a_2.7
http://www.e30zone.net/e30zonewiki/inde ... ding_a_2.7
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daimlerman
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This is one off those 'How long is a piece of string?' questions!
Using a 731 head and a stock 325 BMW cam,mine made 174bhp,with a flat torque curve from 2000rpm to 5300rpm at 180ft lb.
A lumpy aftermarket cam will move the power further up the range and reduce the low down torque.
I currently have a stock 323 BMW cam,engine now pulls cleanly to the red line,but as yet I have not had the chance for a r/r run.
Using a 731 head and a stock 325 BMW cam,mine made 174bhp,with a flat torque curve from 2000rpm to 5300rpm at 180ft lb.
A lumpy aftermarket cam will move the power further up the range and reduce the low down torque.
I currently have a stock 323 BMW cam,engine now pulls cleanly to the red line,but as yet I have not had the chance for a r/r run.
Youth is wasted on the young.
i suppose what i should have put is compared to say a stock 325i or eta - i take it even though yours has similar power to a 'good shape' b25, it is very tourquey?
I will be using an early eta block, 885 head and standard cam, with 325i inlet and exhaust log manifold - for pure cheapness. See how that is as a base line then go from there - better suited cam, manifold etc.
i was concerned with the compression btw as regards to LPG
I will be using an early eta block, 885 head and standard cam, with 325i inlet and exhaust log manifold - for pure cheapness. See how that is as a base line then go from there - better suited cam, manifold etc.
i was concerned with the compression btw as regards to LPG
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daimlerman
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I cannot remember what the CR is with that combination,9.5 or 10.1 rings bells but I cannot be sure!
I was all set to fit the bigger valves when I swapped cams,but was talking to Andyboy about it and he suggested that doing so would affect the lowdown torque that I enjoy so much in favour of a little more power at the top end,where I rarely go!
Never tried LPG with an E30 myself,but my gut feeling is that you will like the result.
I was all set to fit the bigger valves when I swapped cams,but was talking to Andyboy about it and he suggested that doing so would affect the lowdown torque that I enjoy so much in favour of a little more power at the top end,where I rarely go!
Never tried LPG with an E30 myself,but my gut feeling is that you will like the result.
Youth is wasted on the young.
thanks. how could I not after only ever driven an m20b20! im sure even a b25 would put a smile on my face! but im saving that engine for the 3.2 build. Ill have to see if anybody on here uses LPG on a 2.7, rings a bell that somebody does. Need to upsize my mixer
chris
chris
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StuBeeDoo
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That will be me then.CHR1S1990 wrote:Ill have to see if anybody on here uses LPG on a 2.7, rings a bell that somebody does. Need to upsize my mixer
What type of mixer are you using now, and what size is it?
This is why I no longer drive an E30......
There you are! do you know, i couldnt even tell you! I put it on over a year ago now, and i bought it listed as a 325i mixer, who also didnt know the size. Its absolutely perfect for an m20b20 though - idles well and doesnt feel like ive lost any top end. if anything its improved on lpg as it ran extremely rich on petrol.
what size are you using?
i havent used petrol in over a year - i always start on gas too (starts every time
) so I was thinking of removing the AFM and keeping it in the boot if I ever need it, then buying the cylindrical type mixers they use on landrovers etc. That way I can do away with the cat flap too, bonus
what size are you using?
i havent used petrol in over a year - i always start on gas too (starts every time
) so I was thinking of removing the AFM and keeping it in the boot if I ever need it, then buying the cylindrical type mixers they use on landrovers etc. That way I can do away with the cat flap too, bonus-
StuBeeDoo
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I've got the Land/RangeRover cylindrical mixer with a 39mm venturi in and it's about right. I tried 42mm & 45mm venturis and my Leo couldn't get the mixture rich enough. To get the idling at somewhere near the right speed (1k rpm) I've had to set the parameters on the Leo so that the mixture at idle is weak. I figured that as long as it's only at idle when the engine is under no load it shouldn't do any harm. As soon as I touch the throttle pedal the Leo does its job properly. This also has a spin-off that there's less LPG used on the over-run. I did experiment with actually using the over-run cut-off facility on the Leo, but the transition from cut-off to not gave the car a nasty jerk.
There is an alternative to removing the AFM. I've got an "Iwema L-jet opener". It holds the AFM flap wide-open all the time you're running on gas, and has the bonus of not needing a "cat-flap".
The only issue I've got with running the 2.7 with LPG is that with less than half a tank of gas, if I give it some beans (above 4k rpm) the mixture sometimes goes weak and causes the engine to hesitate. This is likely a flow problem with my system. I haven't bothered doing anything about it as I rarely go over 4k, I mostly make use of the bucketfuls of torque.
I have to say that I'm not over-impressed with the actual LPG consumption - 17-18mpg commuting and 22-23mpg touring - but it terms of financial cost, I can live with it as the car is cheaper to run than my wife's '09 Fiesta, which returns 35-40mpg on petrol. It's just a pain remembering to fill-up at 170miles day-to-day or just over 200miles on a run. If I could get a realistic touring range of 250 miles I'd be happier, but I'm just nit-picking, really. I'd love to be able to get Ant to remap it specifically for LPG, but being over 300 miles away from him it's difficult. I've read that LPG-specific ignition timing can possibly improve consumption by up to 20%. I'd like some of that!!
I'm on my second 2.7 engine and for this build I went for torque rather than BHP. I don't have any hard-and-fast figures, but I'm happy with it as it is. It's basically an eta bottom-end with all M20B20 top-end other than a 325i cam and TB. The only non-torque-orientated part is the sub-6kg flywheel. It's purely personal, but I kept away from the 885 'head and stuck with the 731, simply because of the higher c/r and smaller valves being better for mid-range. My first 2.7 (I didn't build it) also had the 731 head, but the ports had been enlarged to 885 size and 325i valves had been fitted and it had the 325i inlet manifold. Again, I had no figures for it other than the seller's claim of 190/190 but that one was definitely less bottom-end and more more top-end orientated. Of the two, I have to say that I much prefer the new engine's power delivery over the old one - but then again I'm getting older and I find that revving the bollocks off it is tiresome.
I rarely need to use petrol, either. I've found that as long as the ambient temperature is above about 7degC it will start on LPG.
Hope this is of some help. If you need to know anything else, I'll gladly help if I can.
Cheers
Stuart.
There is an alternative to removing the AFM. I've got an "Iwema L-jet opener". It holds the AFM flap wide-open all the time you're running on gas, and has the bonus of not needing a "cat-flap".
The only issue I've got with running the 2.7 with LPG is that with less than half a tank of gas, if I give it some beans (above 4k rpm) the mixture sometimes goes weak and causes the engine to hesitate. This is likely a flow problem with my system. I haven't bothered doing anything about it as I rarely go over 4k, I mostly make use of the bucketfuls of torque.
I have to say that I'm not over-impressed with the actual LPG consumption - 17-18mpg commuting and 22-23mpg touring - but it terms of financial cost, I can live with it as the car is cheaper to run than my wife's '09 Fiesta, which returns 35-40mpg on petrol. It's just a pain remembering to fill-up at 170miles day-to-day or just over 200miles on a run. If I could get a realistic touring range of 250 miles I'd be happier, but I'm just nit-picking, really. I'd love to be able to get Ant to remap it specifically for LPG, but being over 300 miles away from him it's difficult. I've read that LPG-specific ignition timing can possibly improve consumption by up to 20%. I'd like some of that!!
I'm on my second 2.7 engine and for this build I went for torque rather than BHP. I don't have any hard-and-fast figures, but I'm happy with it as it is. It's basically an eta bottom-end with all M20B20 top-end other than a 325i cam and TB. The only non-torque-orientated part is the sub-6kg flywheel. It's purely personal, but I kept away from the 885 'head and stuck with the 731, simply because of the higher c/r and smaller valves being better for mid-range. My first 2.7 (I didn't build it) also had the 731 head, but the ports had been enlarged to 885 size and 325i valves had been fitted and it had the 325i inlet manifold. Again, I had no figures for it other than the seller's claim of 190/190 but that one was definitely less bottom-end and more more top-end orientated. Of the two, I have to say that I much prefer the new engine's power delivery over the old one - but then again I'm getting older and I find that revving the bollocks off it is tiresome.
I rarely need to use petrol, either. I've found that as long as the ambient temperature is above about 7degC it will start on LPG.
Hope this is of some help. If you need to know anything else, I'll gladly help if I can.
Cheers
Stuart.
This is why I no longer drive an E30......
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StuBeeDoo
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I should have added.....
IMHO the eta pistons are far too big and heavy for an engine that gets revved hard.
IMHO the eta pistons are far too big and heavy for an engine that gets revved hard.
Last edited by StuBeeDoo on Sun Oct 17, 2010 1:04 pm, edited 1 time in total.
This is why I no longer drive an E30......
Any chance of a picture of your mixer setup?
My 320i returns 22.5mpg commuting and have got up to 31mpg on the motorway (i dont do this often) so perhaps there might be some room for improvement there?
I use a large 80ltr tank in the boot so filling up isnt a problem, however it is one heavy SOB.
Intersting. I must admit i do like a screamer, but then again i'm used to my m20b20 (which actually has a lot of poke on lpg regardless of how much people slag bottom end power off)
How does it feel to drive on petrol? I think im quite lucky with my setup - when it gets into the minus temperaturs, i can still start on gas no problem.
Based on what you have said, I think for pure cheapness (i have most if not all parts already), i'l put it together as follows:
eta bottom end, left alone (wont change to 2.5 pistons, though i do have some high comp ones) - it's only done under 100,000 miles, and is off an auto and is apparently in good condition - will have this couriered by wednesday
my spare 885 head - i'l get it tested&skimmed, get all the valves lapped in and leave the standard 325i cam
325i inlet & log manifold
swap over all the motronic 1.3 parts and just use the original loom
upgrade my mixer to a 39mm ish cylindrical one and either remove AFM or use an "opener" as you describe
Then when i remove my m20b20, i can rape it of the head to swap over. Then decide whether to go down your route i.e.
leave it be and recon, or swap over some of the bigger valves and a lumpier cam
are the pistons way to heavy for the extra revs needed with the above - m20b20 head and larger valves/cam?
thanks
p.s. good info there drew, cheers
My 320i returns 22.5mpg commuting and have got up to 31mpg on the motorway (i dont do this often) so perhaps there might be some room for improvement there?
I use a large 80ltr tank in the boot so filling up isnt a problem, however it is one heavy SOB.
Intersting. I must admit i do like a screamer, but then again i'm used to my m20b20 (which actually has a lot of poke on lpg regardless of how much people slag bottom end power off)
How does it feel to drive on petrol? I think im quite lucky with my setup - when it gets into the minus temperaturs, i can still start on gas no problem.
Based on what you have said, I think for pure cheapness (i have most if not all parts already), i'l put it together as follows:
eta bottom end, left alone (wont change to 2.5 pistons, though i do have some high comp ones) - it's only done under 100,000 miles, and is off an auto and is apparently in good condition - will have this couriered by wednesday
my spare 885 head - i'l get it tested&skimmed, get all the valves lapped in and leave the standard 325i cam
325i inlet & log manifold
swap over all the motronic 1.3 parts and just use the original loom
upgrade my mixer to a 39mm ish cylindrical one and either remove AFM or use an "opener" as you describe
Then when i remove my m20b20, i can rape it of the head to swap over. Then decide whether to go down your route i.e.
leave it be and recon, or swap over some of the bigger valves and a lumpier cam
are the pistons way to heavy for the extra revs needed with the above - m20b20 head and larger valves/cam?
thanks
p.s. good info there drew, cheers
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StuBeeDoo
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22.5mpg on LPG commuting? You lucky sod! My 2.0 wasn't very much better then the 2.7. 
I don't think I ever got over 25mpg with the 2.0 on a run, and I regularly do 300+ mile cross-country (m/way + A-road) runs. 
I used to regularly rev my 2.0 to 6.5k on LPG with no problems. Typical 2.0, it thrived on revs, particularly with the 2.5 TB fitted.
How does mine drive on petrol? I don't suppose it's any different to how it is on LPG, but it's difficult to appraise it as I've never driven it more than a quarter of a mile on petrol.
As you mentioned "cheapness", I have to say that if I were in your situation I wouldn't bother swapping 'heads for the hell of it. I've done 2 'head jobs now and neither time have I got much change out of £500. When I built my current engine I originally planned to experiment with different 'head specs and different camshafts. I've since decided that due to the costs involved I'll not bother doing anything unnecessarilly. I've got a spare 'head that I could "play" with if I ever have to do another top-end rebuild, but with a completely rebuilt engine just 7k miles old I'm hoping its going to be a very long while before I have to comtemplate any further major work.
I don't currently have any pic's of my AFM, opener, mixer, induction pipe set-up. If I get a chance I'll take some and post them here.
I suspect there are plenty of people running eta engines with either 731 or 885 'heads who rev them hard with no problems. My "heavy pistons" comment is something that has only recently occurred to me. It's a given that high-revving engines don't use heavy pistons. Actually, my last 2.7 I revved to 6k more than a few times and I never thought anything of it. It's only since I've built the latest one that I've come to the conclusion that going much beyond 5k doesn't achieve very much. I suspect that because I deliberately built this engine for low-mid range it "runs out of breath" beyond 5(ish)k rpm.
I don't think I ever got over 25mpg with the 2.0 on a run, and I regularly do 300+ mile cross-country (m/way + A-road) runs. I used to regularly rev my 2.0 to 6.5k on LPG with no problems. Typical 2.0, it thrived on revs, particularly with the 2.5 TB fitted.
How does mine drive on petrol? I don't suppose it's any different to how it is on LPG, but it's difficult to appraise it as I've never driven it more than a quarter of a mile on petrol.
As you mentioned "cheapness", I have to say that if I were in your situation I wouldn't bother swapping 'heads for the hell of it. I've done 2 'head jobs now and neither time have I got much change out of £500. When I built my current engine I originally planned to experiment with different 'head specs and different camshafts. I've since decided that due to the costs involved I'll not bother doing anything unnecessarilly. I've got a spare 'head that I could "play" with if I ever have to do another top-end rebuild, but with a completely rebuilt engine just 7k miles old I'm hoping its going to be a very long while before I have to comtemplate any further major work.
I don't currently have any pic's of my AFM, opener, mixer, induction pipe set-up. If I get a chance I'll take some and post them here.
I suspect there are plenty of people running eta engines with either 731 or 885 'heads who rev them hard with no problems. My "heavy pistons" comment is something that has only recently occurred to me. It's a given that high-revving engines don't use heavy pistons. Actually, my last 2.7 I revved to 6k more than a few times and I never thought anything of it. It's only since I've built the latest one that I've come to the conclusion that going much beyond 5k doesn't achieve very much. I suspect that because I deliberately built this engine for low-mid range it "runs out of breath" beyond 5(ish)k rpm.
Last edited by StuBeeDoo on Wed Oct 20, 2010 5:13 pm, edited 2 times in total.
This is why I no longer drive an E30......
I have a 2.7 engine for sale if u are interested
http://www.e30zone.net/modules.php?name ... highlight=
http://www.e30zone.net/modules.php?name ... highlight=
S54, S62, S65 & S85 Plug & Play loom/Ecu Kits
Sump Baffles
Engine Conversion Kits/Parts
TrackDays
Sump Baffles
Engine Conversion Kits/Parts
TrackDays
i thought it was quite economical too. What state is your LPG kit in? Only second hand thing i bought was the tank. Glad I did this as it made for a very easy setup.
ok, well as I already have an 885 head in the garage I will just put this on the eta block. I know the compression ratio wont be the highest, but from what Ive read its hardly lacking in power/torque. Block came yesterday btw, bores look fine (still see hone marks too) and pistons have no valve damage. Think I will just clean it up, paint it, then bolt it all together ready for dropping in on my christmas break. Quick question - i take it I can remove the pistons/shells and put it all back together (for cleaning) with the same rings etc (assuming all are within tollerances)? Which bolts are stretch bolts on the bottom end?
Engine code reads 27 6E A btw. What does the A refer to?
Money no option, which would be the preferred build for power/torque -
Early ETA pistons 731 head with 325i port/valve sizes or
Early 325i pistons and 885 head (with the obvious decking/vernier pulley etc)
keeping in mind as much as low end torque is great, I am young and i do like lumpy cam screamers
I have all these parts, only the 731 head is bolted to my 320i engine lol Its more of a learning curve for me than anything building engines. Id rather spend my money swapping heads and playing about with engines than blowing it all on something student-like (being only 20)
thanks for your input
already have all the parts I need turk, but cheers anyway
ok, well as I already have an 885 head in the garage I will just put this on the eta block. I know the compression ratio wont be the highest, but from what Ive read its hardly lacking in power/torque. Block came yesterday btw, bores look fine (still see hone marks too) and pistons have no valve damage. Think I will just clean it up, paint it, then bolt it all together ready for dropping in on my christmas break. Quick question - i take it I can remove the pistons/shells and put it all back together (for cleaning) with the same rings etc (assuming all are within tollerances)? Which bolts are stretch bolts on the bottom end?
Engine code reads 27 6E A btw. What does the A refer to?
Money no option, which would be the preferred build for power/torque -
Early ETA pistons 731 head with 325i port/valve sizes or
Early 325i pistons and 885 head (with the obvious decking/vernier pulley etc)
keeping in mind as much as low end torque is great, I am young and i do like lumpy cam screamers
I have all these parts, only the 731 head is bolted to my 320i engine lol Its more of a learning curve for me than anything building engines. Id rather spend my money swapping heads and playing about with engines than blowing it all on something student-like (being only 20)
thanks for your input
already have all the parts I need turk, but cheers anyway