| Welcome to Mercedes-190.co.uk We are the Mercedes 190 owners forum, the place to be for all owners and fans of the Mercedes 190E, 190 and 190D cars. Including Cosworth (2.3 16v and 2.5 16v), EVO 1 and EVO 2 models. Modified and concourse, track cars and daily drivers, all are welcome. This free UK based forum was started back in November 2005 to serve the Mercedes 190 W201 community and now has over 9000 members from all around the world and 600,000 + posts. The members welcome you and encourage you to stay a while and have a look around. We offer you friendly chat and access to some very useful information as well as tutorials with photos and videos for many common repair and maintenance jobs. Whatever your needs there is a good chance you will be able to find what your looking for. Such as our Mercedes 190 buyers guide Sign up to gain access to all areas including for sale / classified areas and country wide meetings and events. Many forum features and sections are only available once you sign up. Join our forum at mercedes-190.co.uk! If you're already a member please log in to your account: **New members signing up** please check your junk mail for the email authorization email otherwise we cannot verify your new account. I have noticed a lot of unauthorized accounts in the system. Regards Admin |
| 16v naturally aspirated tuning thread; (Non EFI discussion) | |
|---|---|
| Tweet Topic Started: Tue May 11, 2010 2:07 pm (4,433 Views) | |
| pentoman | Tue May 11, 2010 2:07 pm Post #1 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
I have got a hold of this program which is an engine simulation and lets you input all the figures for an engine and try out different things to see how they would *theoretically* change the power output of the engine. It might help us look at the areas for improvement in the 16v and what the likely impact is. E.g. higher performance cams are an easy power gain but how much torque do you lose? I am leaving out EFI discussion, there are other threads on that. I've started doing it for the 2.5 just because that is what I have, but this can easily be changed for another engine. Few things I could do with knowing: 1) What size are the valves on 16v? I want to say they are all 35mm valves for some reason? FYI the difference between 35mm and 40mm valves is about 8hp across the rev range. 2) As you can see I have had to choose the default in-built 'ported head with large valves' option because I don't have the exact flow figures to go in the boxes. However didn't somebody post flow figures once? Can someone point me to them please? ![]() 3) I don't know about the induction - 600cfm @ 1.5 inHg what is this!? Do we have individual runners? I think we do because there is an individual air runner to each cylinder. (although still just a single throttle body). ![]() If I choose individual runners I get this curve which is a lot like the stock 2.5-16 curve: ![]() Note power is the red line and torque is the green line. See how torque peaks about 4500rpm and power peaks around 6000rpm just like the 16v? And peak power is 194hp@6000 which is about right for a 2.5-16? Although the torque peak of 200lbft is way off, so perhaps I have got something wrong. If I change the intake runner to any other type then it boosts power a lot at the top end to 220bhp@7000, but sacrifices torque quite a lot, only peaks at 192lbft and its higher up the rev range as well: ![]() So note how in the original curve the torque is boosted at around 4500rpm but the power curve levels out or tails off over 6000rpm just like the 16v does according to the factory curve and to the dyno curves I have seen. I always suspected the long metal intake tubing on the 16v boosted torque a lot but strangled the peak HP - perhaps this is proof? I would also like to compare with Evo II - does anyone have part numbers? 4) Cams. I have had to use the valve timing figures for the catcams cams for the 16v that were for sale. Because I couldn't find the stock figures for the 16v. If anyone knows these it would be good and would help us look at what difference cams would make. Note that all these graphs are with these sport cams fitted because I didn't have the factory cam figures. I think someone like 'racing' should have these. ![]() There is a function which finds the best cam timing for your current setup, but interestingly when I use that I can only gain max 4hp. So from this it doesn't look like cams are holding the engine back. Probably due to that intake runner mentioned above? Anyway I know this is a simulation but it claims to be very accurate. If we could get the right figures in there we could look at what improvements are possible. It doesn't simulate variable valve timing etc but that's fine because the 190E doesn't have any of that! 6) One more thing - if you change the compression ratio for a 2.5-16 up to 10.5:1 then you gain about 5hp and 5 lbft throughout the whole rev range, which would feel very nice, like having a bigger engine. The reason I mention this is because the 2.3-16 already has a 10.5 compression ratio. For some reason Mercedes lowered it on the 2.5 model. I wonder why? So that's one area the 2.3 is superior to the 2.5 (although it may also make the 2.3 more fragile as well). Also the e30 m3 has 10.5 compression ratio. Thoughts please maybe from our German tuning friends? I will keep playing and researching to see what I think. But it really seems like even with a high flowing head having ' |
![]() |
|
| pentoman | Tue May 11, 2010 2:44 pm Post #2 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
OK I think I was wrong about the intake runner. We actually have a single-plenum design. Also more about cam timing, apparently lift on the 2.5 is 9.5mm. Lift on the e30 m3 is 10.27mm. Duration on the m3 is 248 according to http://www.s14.net/forums/showthread.php?t=37714&page=3 but they all go to 280ish duration. One guy is using over 300 duration on his cams but also with 13:1 compression ratio pistons apparently! Makes 260+hp. Just using these m3 figures as reference because there is not a lot available for the 190. Anyone know the duration of the stock 190 16v cams? Would be nice to have these. Edited by pentoman, Tue May 11, 2010 2:50 pm.
|
![]() |
|
| RobertE | Tue May 11, 2010 3:08 pm Post #3 |
|
Serial victim...
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]()
|
The cfm number is cubic feet per minute, chap. Jesper posted about this ages ago, I recall. Someone found the post, but I could not. I've just been to inspect one of the spare cylinder heads I have and q. honestly I can't really see much room for improvement. Obviously, I concluded, the density of the casting itself allowed Cosworth to design and build it with the maximum of post-casting machining, but any more would, I think, be a risk. I have never heard of examples of Cosworth cyliner heads going 'porous', (not like, say, a Leyland one) so I assume that the metal is a) sound and b) as good as they could make it. Top job! |
![]() |
|
| RobertE | Tue May 11, 2010 3:10 pm Post #4 |
|
Serial victim...
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]()
|
Also, google catcams in Ditchling, Sussex. They'll sell you a pair of Evo 2 - spec cams for (iirc) less than £600. But you only need the inlet... |
![]() |
|
| bolide | Tue May 11, 2010 3:41 pm Post #5 |
|
Bolide
![]() ![]() ![]() ![]()
|
That looks very oriented towards American engines & tuning methods. Yanks quote carburettor sizes in CFM and I associate all that "Dual-plane high-torque" stuff with V8 tuning Still, a useful tool to play with "What-Ifs?" If you can get it to give a reasonably accurate power output for a standard engine then you should be able to see what kind of gains you'll get from more revs, wilder cams, etc Are they quoting outputs in BHP or HP SAE (Silly American Estimate)? Nick Froome www.w124.co.uk |
![]() |
|
| cosser | Wed May 12, 2010 12:18 pm Post #6 |
|
Part of things
![]() ![]() ![]() ![]()
|
Hi Pentoman, here's some data on the valves ![]() ![]() Cosser..!! |
![]() |
|
| jeremy | Wed May 12, 2010 12:39 pm Post #7 |
![]()
Too Far Gone To Help
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]()
|
This looks fascinating . Shame I can't understand it . Jeremy |
![]() |
|
| rhysmangatmotorsport | Wed May 12, 2010 2:46 pm Post #8 |
|
Mangatmotorsport
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]()
|
nice one, good info.. |
![]() |
|
| pentoman | Wed May 12, 2010 7:33 pm Post #9 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
OK Thanks cosser - have not got correct valve sizes in there. I think the next thing we really need is the camshaft timings - they seem to make a big difference now I have got the correct intake type (d'oh!). I also think Jesper posted CFM and all those numbers for the 16v head, but can't find it. Edited by pentoman, Wed May 12, 2010 7:36 pm.
|
![]() |
|
| alogaparaloga | Wed May 12, 2010 8:44 pm Post #10 |
|
crazy mind
![]() ![]() ![]() ![]() ![]()
|
Hi mate. glad to see other members trying to model their engines. I have tried the same software you are using to simulate various engines, but the results are not reliable enough. It is good to have these results as a general guide but you cannot depend on them. I have done my own static models for petrol engines using excel, with quite good results and I go as far as Otto cycle and chemistry. What I cannot understand with this software is what algorithm they run in the background for flows and fuels which are the most important. |
![]() |
|
| cosser | Thu May 13, 2010 11:13 am Post #11 |
|
Part of things
![]() ![]() ![]() ![]()
|
Hey pentoman, Is this what you're looking for..?? ![]() ![]() Cosser..!! |
![]() |
|
| matsalleh76 | Thu May 13, 2010 11:41 am Post #12 |
|
Matsalleh76. RIP. Gone But Never Forgotten.
![]() ![]() ![]() ![]()
|
Quick question: What is the confirmed 2.3/2.5-16 combustion chamber volume? I understand (but am open for correction) that the combustion chamber volume on a 2.3/2.5-16 is ~56cc. Please confirm/correct, etc. etc. One of Cosser's screen prints with the volume and combustion chamber dimensions would be wonderful. Thanks, bobf. |
![]() |
|
| cosser | Mon May 17, 2010 11:11 am Post #13 |
|
Part of things
![]() ![]() ![]() ![]()
|
Hey guys, I thought you calculated the cylinder volume by dividing the total volume by the number of cylinders..?? i.e. 2299 / 4 = 574.75 cc per cylinder..?? Cosser..!! |
![]() |
|
| alogaparaloga | Mon May 17, 2010 1:39 pm Post #14 |
|
crazy mind
![]() ![]() ![]() ![]() ![]()
|
Cylinder volume differs from combustion chamber volume. Combustion chamber volume is the volume on the cylinder head + the volume of Deck height. Deck height is given by the distance of piston land at TDC to the block surface + the thickness of the head gasket. |
![]() |
|
| pentoman | Mon May 17, 2010 9:03 pm Post #15 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
Hello. Yes, thankyou, those are useful. They will also be useful for anyone doing any tuning with the 16v, to know what the standard cams are and therefore how aggressive or reserved they are. According to those figures (EDIT THESE FIGURES ARE WRONG - SEE NEXT POSTS), it gives us a 231 Exhaust duration and a 225 intake duration (seat to seat). Just looking up some other cars for reference, the duration on a 1995 3.0 M3 (286bhp) is 260/260. From what I read a race car will use over 300 duration, so that's a far distance and a big power gain there (at high revs, if it's not strangled by the intake system, and while sacrificing low down torque) @alogaparaloga: Yes, now I have played with this some more I think it is a very clever model, but not a simulation. I.e. it guesses at what the results will , using real life examples etc. But it is just guessing mathematically really. As opposed to genuinely simulating all parts of the engine. Edited by pentoman, Mon May 17, 2010 9:17 pm.
|
![]() |
|
| pentoman | Mon May 17, 2010 9:14 pm Post #16 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
OK Now I cam confused. From Cosser's readings, the exhaust valve closes before TDC, and the intake opens after TDC. This means there is no overlap. (Overlap being when both valves are open - I think common on racing cars etc & it gives them a lumpy idle??). However in the program I cannot find a way to input this. It will only take an input that has a minimum overlap of 0. Otherwise it asssume you want some overlap??
|
![]() |
|
| pentoman | Mon May 17, 2010 9:27 pm Post #17 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
OK Corrections. The seat-to-seat intake and exhaust durations for the 2.5-16, calculated using a web calculator thing, according to data from cosser's data sheets, are: 2.5-16: Intake 209 degrees. Exhaust 211 degrees. Which sounds very mild. Potential for improvement there? For the 2.3-16 (EURO???) these are the figures: intake 199 degrees exhaust 199 degrees Which sounds even more mild. And makes it impressive the 2.3 makes such good power with what appear to be less aggressive cams (but a higher compression ratio). However before believing the figures, I would like to be sure this is the 2.3 EURO not the 2.3 US which is detuned and has milder cams! Evo 2 is: intake 219 degrees exhaust 211 degrees Anyway that is all for now. All setups have no overlap at all. The thing with cams is that I think racy cams can upset the KE Jetronic. I think with overlap you get some back-pulses down the intake which moves the flap in the intake backwards, and really screws up the fuel flow. Can't remember where I read that now. |
![]() |
|
| alogaparaloga | Mon May 17, 2010 9:33 pm Post #18 |
|
crazy mind
![]() ![]() ![]() ![]() ![]()
|
True Pentoman I used the wrong words. Actually the mathematical calculations to predict performance are called static modeling. It's needed to do the correct assumptions to have reasonable results but is a bit difficult to be spot on without considering AFR and ignition timing. Otherwise a good general guide. |
![]() |
|
| matsalleh76 | Tue May 18, 2010 12:18 am Post #19 |
|
Matsalleh76. RIP. Gone But Never Forgotten.
![]() ![]() ![]() ![]()
|
There is overlap. Use these figures to calculate same: Cam Timing: ……………...........................2.3-16...................2.5-16/EVO…....EVO2 Intake valve opens:…….....7 deg ATDC.....................7..................7 Intake valve closes:……...26 deg ABDC...................37.................47 Exhaust valve opens:…....32 deg BBDC....................41..............37 Exhaust valve closes:…....13 deg ATDC....................11...............7 Regards, bobf Edited by matsalleh76, Tue May 18, 2010 12:23 am.
|
![]() |
|
| alogaparaloga | Tue May 18, 2010 8:33 am Post #20 |
|
crazy mind
![]() ![]() ![]() ![]() ![]()
|
True that pressure waves will force the AFM plate to close but the main problem is that the fuel system is a continuous injection system and AFR is prone to ignite during cam overlap as there is some mixture pushed back to the intake system from the cylinder. This happens to a limitted rev range though and depends on how large overlap. Edited by alogaparaloga, Tue May 18, 2010 8:38 am.
|
![]() |
|
| Chris Martens | Tue May 18, 2010 1:01 pm Post #21 |
|
Part of things
![]() ![]() ![]() ![]()
|
some remarks; The cam timing data according to Daimler is at 2 mm lift! Most data for duration is at 0mm lift or near 0mm, comparison of data from 2mm / 0mm lift is near to impossible because you don't know the lift per deg of the cam until you messure it. Jesper's diagram of the flow can be seen here on the rev. This engine simulation program looks interesting. What's the name and where can I get that program? regards, Christian |
![]() |
|
| alogaparaloga | Tue May 18, 2010 3:03 pm Post #22 |
|
crazy mind
![]() ![]() ![]() ![]() ![]()
|
Software is called DYNO 20XX depending the year of release |
![]() |
|
| pentoman | Tue May 18, 2010 8:01 pm Post #23 |
![]()
Resident OVP Expert
![]() ![]() ![]() ![]() ![]() ![]()
|
@All - yes, once again I have made a mistake, and written values for 2mm lift (0.078") not 0mm lift which I first claimed. Therefore this has to be taken into account. NB I used the figures for a used timing chain. @Chris - thanks for the link @alogaparaloga - interesting words about the overlap problems with continuous injection. |
![]() |
|
| 1 user reading this topic (1 Guest and 0 Anonymous) | |
| « Previous Topic · Engine · Next Topic » |








![]](http://z2.ifrm.com/static/1/pip_r.png)













2:03 AM Jul 11