Time to order the new camshaft

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marc

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Dose any body have any idea what I should set my red line at ? The new engine has been run on the dyno using emerald programmable ecu but with a standard 3.0 csl cam shaft. I have now come to order the cam shaft and need to no at what point i need to make full power.
So far we are pulling 253 bhp 5400 rpm (fly wheel) but I wanted to make the peek power at around 7000- 8000 rpm.
Any body any Idea how you work out a safe red line limit ?

marc
 
Marc

If your current engine specs are "standard" CSL then set it at the factory limit for the engine to start with.
However.......
The physical rev limit is usually determined by the valve springs, you have to avoid "valve bounce" ie the valve doesn't have time to close completely before the lobe of the cam comes around again
If your going for a "fast road" or race cam profile you need to uprate your valve springs. W&N in Germany would be a good place to start

Your quoted power ouput is pretty impressive right now, even if its at 5400. Why do you want to move it up the rev range :?:

Anyway......
Where you get peak power in regard to the rev range is determined by many factors including, but not limited to:

1...Cam profile
2...Valve size and style (4 valves per cylinder versus 2)
3...Stroke of the engine generally long stroke - max power/torque at lower revs compared to a short stroke or "oversquare" engine.
4...Inlet tract lengths - generally short means peak power/ torque at higher revs, longer ones lower down, with more torque.
5...Throttle body size - physical amount of air that can get into the engine
6... Porting of the engine - air flow path

Basically with the design of this engine it will be very difficult to move the power way up the rev range, you can increase the power but moving the power would mean having to bolt on a BMW racing cylinder head as per the racing E9s
Open your wallet and say after me - help yourself!

I have built rally car engines, fiat 1500cc with Abarth cams and valve springs, added an extra 1500 rpm to about 8000rpm before valve bounce occured.
That stated peak power was at about 6000 after I had finished with it
However that engine was dynamically balanced, including the clutch assembly, ported, different injectors, cold air ducting, electric rather than mechanical water pump.... the list goes on!

For stage rallying it was handy to "hang" on to a lower gear sometimes, but it was a bit of a pig at low speeds....


I would be very interested in your Emerald ECU setup, could you let me know how you did it?

Cheers
Malc
 
Hi Malc
The emerald ECU is just what the engine shop had built into his dyno (a friend is doing the work, he works for a well known firm of formula 2 engine builders) but I think I`m going to use one on the car when I fit the engine.
The bottom end is running on a forged crank with a 88 mm stroke , Carrillo H beam rods at 143mm between bearing centers and JE forged pistons (94 mm bore) with reduced deck height to give 11-1 compression with a 35cc head pocket. All the parts have been balanced and running on Clevite 77 race bearings. The head is fully ported with 48mm in let and 40 mm exhaust valves (angled valve stems to get them to fit) running on some special steel rockers, schrick valve springs with Ti retainers and Ti rocker arm locks to remove the springs that keep the rockers on rocker shaft. I am also using a vernier adjustable cam sprocket and single timing chain.
edit...its 65mm head volume not 35mm
For timing I`m using a standard CSL disi with the advance and retard plate locked and the timing controlled by the ecu. I`m also not using a O2 sensor just a standard d-jet throtle position indicator, manifold air pressure sensor and water and air temp sensors
For the in let side of things I`m using standard d jet `log` but with the throttle housing bored out by 2 mm and a larger throttle butterfly and all the intake runners have been flowed to match the enlarged in let ports.
Still running it on a standard exhaust manifold for the time being.
Steve my engine guy tells me the only limiting factor for HP and torque is how hard I rev the engine and with a program they have run is Built in to the dyno, it estimates that it would produce 270 bhp at 6000 rpm, 290 bhp at 6500, 312 bhp at 7000 rpm , 340 bhp at 7500 rpm and 360 bhp at 8000 rpm injectors permitting (currently running I think 40lb injectors at 60% duty cycle with 28 lbs fuel pressure)
I`m just unsure were to go with the red line for the cam shaft profile, I want good top end power but I still want some low down.
any help would be greatly received... I can then order yet another set of new injectors.
marc
 
Woah
That's some serious stuff!
Sounds like the engine is pretty much prepped for racing. THe only other thing I can think of to squeeze more BHP out is the exhaust and exhaust manifold, which is a big problem for RHD cars unless you fabricate a manifold forwards and then down and around the engine!

Understand about the "prediction" software from the Dyno, The question is can you use that power at those revs? If your racing the car then fine otherwise it's alot of noise in the highstreet :wink:
BTW are your figures calculated at the flywheel or at the wheels?

Definitely interested in more info regarding the emerald ECU and setup
as my old d-jet is pretty stuffed......
Cheers
Malc
 
Perpetual Duration?

To put it kindly, what we have here is a failure to communicate. An engine will respond to a camshaft profile within the RPM range that specific duration of valve opening and closing provides air flow - period. To state that it will generate more power the harder you push it is absolutely false, as at some point the engine is moving more air through it than the intake system provides and power drops off. This is especially true with older cars that don't have VANOS and other trick stuff the newer cars do. Likewise, there is no ECU from the Magic Forest that will alter this except to maximize the potential of your combination.

Picture your power curve as a flat line with a long bump where the peak power is. The longer the camshaft duration, the further up the RPM range the bump will be, to the detriment of bottom end performance. Since yours is a very stout unit of 3664cc, you could run a more aggressive camshaft than most. A Schrick 292º may be conservative but will provide plenty of power. To get the peak up to 8000 rpm you're talking racing profiles of 316º, not sure if they are suitable for the street. Also be advised that not many of the engine builders recommend redlines beyond 7000, lots of torsional dynamics with that long crankshaft. And as Captain Obvious would suggest, be sure to check the piston to valve clearance.
 
To put it kindly, what we have here is a failure to communicate.......

Well not on my part...... just your assumptions. When I had all the intakes and head gas flowed the whole of the in lets and valves would flow enough air to run 520 horse power at ?? degrees (cant remember temp of the top of my head).
Same goes with the crank, it was machined from a forged billet to take 640 horse power plus nitrous injection in a turbo charged configuration have had to have the counter weights changed to run it normally aspirated.

All I`m doing is trying to get some guidance as to cam shaft profiles so I can determine were to get my power, as its only going to be an occasional driver I did quite fancy a high rpm power band. All the Hp figures are form a standard 3.0 csl cam shaft, we used it as it was the only one we had to hand with the right distributor drive and with an idea of running it by standard d jet injection with increased fuel pressure.

As for piston to valve clearance I bet my guy with 25 years of building formula 2 race engines hasn't even thought about that.

To state that it will generate more power the harder you push it is absolutely false.....
not at all false providing you can flow enough air and cam shaft profile permitting a higher revving engine will always produce more HP power.
 
Mo Power--streetable?

You need to have a chat with either Paul Rosche or Hans Herman for input as to maxing out your interesting "build". Contact me off site for contact with HH--he was very involved in BMW's race programs then and to present date both here in the US and abroad and is a long time friend of PR from the late 1960's. They have worked together many times since on race engine design/development. He may be willing to consult with you on sorting out your challenge.
 
I suppose ultimately it all depends on how much air and fuel you can get in, and out of the engine.
Marc...
alternative thoughts.....
there is some pretty decent software out there for "modelling" engines, Performance Trends is one I can think of off hand as it were, have a rummage on the Web.
I do know somebody who spent a fair bit of money on such a software package. Once he had all the engine info in and twiddled with all the parameters, like cam lift, duration, timing etc he built the engine to the specs suggested.
The real engine came out pretty much as per the model
As he stated, the software cost the better part of £1000 but he would of spent the same amount of money experimenting with a "real" engine and parts, plus it would of taken weeks rather than just a couple of days to find the "ultimate" engine spec he was looking for.
Malc
 
Marc you and I have the same goals I too would like to produce peak power at arround 7-8K rpm unfortunatly my engine will probably have to wait a couple of years after the expense of my restoration. I am a little supprised that you have kept the stock inlet manifold albeit a ported one. As things stand with a 272 degree cam you're fine but you're getting close to the limit of what will work with a plenum chamber and if you go much wilder with the cam you may find that it won't work very well at all. All the literature I've read and the few people I've spoken to tell me that big duration cams and plenum chambers don't work. Putting your question to one side for a moment if I were in your shoes (lucky sod) I'd be looking at putting a set of individual throttle bodies on your motor before upping the cam. This on its own will more than likely yeald an increase in BHP with no detriment to driveability. After all (and with all due respect) no matter how well the porting job was done on your manifold the fact is that the air entering the engine has to make many changes in direction and ultimatly this will cost power.
To answer your question, my honest advice would be to talk to the people who know, the makers of performance camshafts. There are several that spring to mind the most obvious being Schrick but they tend to be very expensive as the do a lot of R+D and have to recoupe their costs then every one else just copies their profiles. Newman cams and also Cat cams (sold through q.e.p in the UK)are a couple of the less well known but excellent brands, google them, give them a call and tell them what you want to achieve and I'm sure they'll be able to tell you what no one on this forum (my self included(no offense guys)) is qualified to.
 
I would have loved to use individual throttle bodies, and I think that is really the way to go. One of my main goals with the CSL engine build was to have it look absolutely standard from the out side. I have spent about 2 years looking for one of the old Alpina inlet manifolds with out success so went for a modified original d jet log and runners. We found most of the obstruction to flow was from the throttle butterfly so it was opened up as far as possible to increase flow, by just under 2mm. I`m going to talk to some cam people next week and get a cam made to get peak Hp at around 7200 rpm and feel confident It should produce around 275-280 bhp. My goal was 270 bhp with an engine was track-able on the street and reliable.

Its been hard work from the start with this engine.... for similar money I could have built a 650 bhp motor for my 930 turbo. That's the next project next year.
thanks for all your help guys, will post the dyno graph results as soon as I get the new cam in. Got to decide now weather to use the 5 speed overdrive box I have or look for a 5 speed close ratio box.
marc
 
Hi Marc, yes I can belive what you have done so far has cost you a serious amount of cash. despite the fact that you have custom rods and pistons which would have cost serious money I'll wager that it was the head and porting work which will have cost the most? From what you said it sounds like you've had the angles of the valves altered, not cheap! I have been studying a lot of facts and figures for the M30 series of engines just recently as I'm starting to make plans for when I do my engine, in fact I posted a question on here a couple of weeks ago as to why the M90 produces peak power so low @5200 RPM the answers I got didn't throw any light on the matter so I started to read up as much as I could and made comparisons between different engines the conclusion that I have come to are just that MY CONCLUSIONS and are by no means set in stone however I'll share them with you to see what you or any one else thinks and who knows if I'm wrong it could save me a lot of time and money. Here goes.

I started to look at specific outputs of different engine and what a saw interested me,generally speaking with reference to the M30 engine, the smaller the engine the higher up in the rev range it produced peak power.
Take for example the E12 5 series
2.5 produces peak @ 6K
2.8 produces peak @5.8K
3.5 (M90 block) produces peak @ 5.2K

The E28 series show similar results except that the 2.5 produces peak at 6.5K! It onlt starts to balance out when the E34 cars were produced and I guess after a lot more R+D.
Interestingly a point to note is that the early 3.0 motors produced 200bhp @5.6K injected and the carburettor version produced 180bhp @6K with the same cam profile and compression ratio.

It is my belief that this anomaly (if you want to call it that) must be due to the induction system, if you think about it logically a smaller engine requires less air and so any restriction (or bad design) in the induction system will be less of a restriction to a smaller engine hence they can "breathe" more freely. It is my opinion that the inlet manifold and plenum chamber on these engines is pants (this has got nothing to do with trying to change your mind about my last post and in any case you didn't even disagree with me) if you want further proof look at the figures for the injected and non injected 3.0 engines. Granted the injected engine produces more power but lower down, this is great if you're Joe Average but not if you want to rev your engine.

If anyone disagrees on me with this one I'm only too happy for you to put forward your opinion as it is something that has bugged me about my motor for a long time.

Gazzol
 
I assumed (wrongly maybe...) it was due to the stroke length increasing with every cubic capacity increase. The 2.5 had Avery short stroke at 71.6 mm the 2.8 having a stroke of 80 mm and the 3.0 had a stroke of 80 mm (but increased bore size) that increased to 84 for the 3.150 cc motor used in the last batch of csl bats (i think). Also they made some 3.3 motors with a stroke off 88mm (i haven't worked out the cc but would imagine it could be a long stroke 2.8).

If your going to build an engine get in touch as I have loads of bits left over from mine, got a fully balanced set of 143mm rods lightened and fluxed etc etc, a original complete 3.0 csl engine that I got of eBay for £50, a 2.8 motor with all inlets, a 3.5 moronic engine and several sets of pistons, heads, valves, springs, rockers (one set fully lightened with micro polished pads) sumps, injectors , exhaust manifolds etc etc.
marc
 
Hi Marc,

I wouldn't be so rude as to say that you were wrong in your assumption it is after all a logical one to make at first sight. However if you delve a little deeper into it the road version of the S38 as used in the E28 produced peak @6.5k rpm and the later E34 derivatives didn't peak until 6.9k. I don't know what the valve timing was on the S38 motors but I would hazard a guess that it wouldn't be more than 280 degrees and more than likely considerably less. Lets assume for a moment that both engines have the same valve duration with the same lobe centre line angle (overlap period) you don't need me to tell you which one is going to produce more power all other things being equal.
So that leaves us with two possible causes for the difference in peak power points in the rpm range. Lets assume we are talking about the M90 block as this has the same bore/stroke as the early S38
One (the only difference between the bottm ends of the motor) is the length of the con rods, but your build throws that theory out of the window.
The other is the induction system, of course the S38 has 24 valves but there is more to it than that. In my experience a 270 degree cam should be more than enough to ensure that peak power occurs at 6K or above.
The more I've looked into this the more conviced I've become that the inlet manifold is to blame. I respect your reasons for not having individual throttle bodies but for me that will be the first thing to get done, heck I might even fit them with the standard management. I am very interested in the spare parts that you have and I note that you may be interested in fitting a dog leg Getrag, I have one of these which I may be parting with shortly as I want to fit a overdriven box for when I tour Europe next year.
If you want to talk about this ofline send me a personal message and maybe we can talk business.

Regards Gazzol[/quote]
 
Gerabox

Marc,
I have a dogleg 5 speed in my scrapper e28 is ok!
would swap for an over drive 5 speed, my missus hated the dogleg box :? so I "promised" a "standard" 5 speed box
Interested?
Malc
 
Where to put your red line depends primarily on your crank. Standard crank has a limit of 8000 rpm. Go above and it flies apart. Not a great sight. Forged crank is a good investment. I hope though Marc you took a good one. It still determines your red line. There are some pretty lousy forged cranks on the market...
Tom
 
Where to put your red line depends primarily on your crank. Standard crank has a limit of 8000 rpm. Go above and it flies apart. Not a great sight. Forged crank is a good investment. I hope though Marc you took a good one. It still determines your red line. There are some pretty lousy forged cranks on the market...
Tom
Click to expand...

All M30 cranks are forged. I think the rods and pistons were cast, though.

Based on what I have seen of high performance M30's , the camshaft profile would move the power band up in the rev range, but only to a point. The head, as others have stated, starts to become a serious problem above 5k RPMs, not so much the cam.
 
Hey marc, I was wondering what you ever came up with as far as a cam? Also I have some questions I'd like to ask as well? I have a similar setup although minus the custom crank and work done to the valves.

I'm running throttle bodies for my intake and I'm running a 307 schrick cam. My peak power is coming from 4 - 7k. I have my redline set at 7k which I think is conservative but safe. But the engine pulls hard all the way up and is in no way falling off at 7.
But I am having some drivability issues that I have yet been able to correct. Nothing terrible but something I want to fix. I'm wondering if I am over cammed.

I can drive it around easy just fine. I can go wot just fine. It’s when I go hard off the bottom then try to stop at a certain rpm like 3500 and settle it wants to act up and buck around. The only way we have been able to make it happy is to take away fuel on acceleration which’s makes it more predictable on transitions but at the expense of response.

So right now I'm just compromising with it. But I'm considering going to a 290 cam. At first I had plans to run the car on the track but now I would rather set it up for fun on the road. I'd cry if I waded it up at the track. :?

So my plan is to just get a dedicated track car instead.
 
Professional input on high performance engine design

marc--don't know from whom you are getting your design advice nor whether you are expecting to have a streetable result from your engine build--as you have not suggested your goals other than bunches of power at very high rpm for an M-30--long cranks--no matter their metalurgy-- have upper reasonable limits that have been suggested to you.

you have apparently ignored my earlier suggestion as to the source I believe to be the best available for your quest--and from your stream of posts there has obviously been a lot of guess work going on--and still is.

Once again-Hans Herman, Doctorate Engineer--is likely the most qualified engine and cam designer around with decades of background regarding the M-30--starting with its original design at BMW in the 1960's--and since a world renowned designer of race and high performance engines for the world auto and race community--add to that background--the key and only engine design collaborator on the most advanced engine design program/system that he and Doctor Blair of the University of Belfast have developed--that undertaking has spanned about 25 years and is ongoing--it is in use by most of the major auto manufacturers and serious International race teams.

The question is--now that you have a lot of spare metal on hand--are you serious and do you still have funds to retain the best? I have known Hans for 25 years. today he is busy designing high performance cams for an impressive array of internal combustion engines--from twins to 12's
 
Well the engine is finished, new cam is installed had 2 week ends on the dyno and all is good... well it is know. With the standard intake runners (flowed and matched to ports) max hp we could get was 262 bhp @ 6800 rpm but with a good fat power curve from 2000 rpm. In the end we dumped the d-jet manifold and log and used a triple Weber manifold with 42 mm throttle bodies for each cylinder and after a day mapping we got good power from 1800 rpm with a peak of 311 bhp @ 7300 rpm. That was using trumpets and individual air filters. I`m currently having a replica alpina type air collector made that will link up to the throttle bodies with curved inlet runners. The engine will be going in the winter and have the appearance of a standard 3.0 csl alpina.
will post full specs when work drops off little and I have some spare pc time.
Its time to start sorting out the suspension/wheels and brakes next and start getting the parts together.
Bluemax, my goal was 280 bhp with reliability and track-able enough through the rev range to use on the road, using modern fuel injection and regular 99 octane pump gas. I (for personal preference) wanted a high revving motor. The dyno shows that at all rev ranges it is producing 25% more bhp and torque from 1800 rpm than the standard engine with a real kick from 4800 rpm. Cost wise its not on reflection its not been to bad, I think around £12k (or about the same cost as a gearbox rebuild on my 246 Dino) I havnt had to pay for a lot of the machine work and its tax deductable...I hope.
marc
 
Great information in this about cams and getting the most out of the venerable M30 but what really interests me is how to make the whole thing TAX DEDUCTABLE!!!!!!!!!
 
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