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Clio 172 Cup Racer
Yeh. Sorry about that Andrew. Fingers crossed it will be at Oulton. Enjoyed your first race thenwell done!
If you think track days are good! Fantastic day, enjoyed every minute. At this rate there could be 10 Clio's in the field next year.
I've heard of 11 so far and could be even more to come! Will be great funIf you think track days are good! Fantastic day, enjoyed every minute. At this rate there could be 10 Clio's in the field next year.
JohnnyE
ClioSport Club Member
ITB'd Clio
BMW 330ci sp/ 172Cup
Update# 20 something - Inlet manifold
Right. before i write up the results of the rolling road day i need to rewind a few months! During the engine build process Mike and I thought we could have a go at making our own inlet manifold! We wanted to see if we cold improve on Renaults design and thought there was some extra potential to be released from our new engine. The idea all stemmed after a flow bench session earlier in the year where we primarily tested our cylinder head but progressed to bolting on the lower inlet followed by the upper plenum. The Upper plenum certainly reduced the cfm figures so that probably planted the seed in our heads - lets make our own simple hey? err, no not really.....
Some pics from the flow bench session (these have already appeared earlier on):
We then started to research what attributes of inlet design affect its performance and how inlets are tuned to suit engine characteristics. To be honet i spent ages reading various "tuning" guides on the Internet and at one point thought this is going to be too hard. I tried focussing on ideas from people with real experience rather than newbies like us There are so many aspects of the design that can alter the result that it started to get a little overwhelming. Early on i even thought about modding the original plenum to improve flow; but a previous thread on here suggested it wasn't a great idea. We also looked at the Stone Automotive RS2 manifold for some guidance. I havent seen one of these in the flesh but the advert images certainly make it look like a very well produced package - one that does a great job of fitting in the engine bay whilst retaining the slam panel. As ours is mainly a track car (when its not broken) we could afford to make some extra space and remove the uneccessary parts - similar to the itb boys.
One thing stood out regarding the design - Runner length! It was this measurement that i thought the RS2 came up a little short on - only to be expected since JMS designed it to be a bolt on/off application. I spent most of my time reading about how to calculate runner length depending on where you want to make the power (torque) in relation to the rev range. I also read how various engine characteristics change the values of the runner. Some of the measurements I used were - inlet cam duration, runner id (initially based around port size in cylinder head) and RPM of max torque. I'm sure others will know that more things need to be catered for, such as stroke, valve size, exhaust effieciency blah blah blah etc but i needed to start somewhere so just used the previously mentioned values. After all - i donnt pretend to know all there is to know about this but just wanted to have a go at making something that might offer an improvement.
Here is my "fag packet" calc sheet
In the end i opted for a total runner length (including head port) of 304mm, precisely - lol. Gut feeling was that our car is built to go round a track so might suit the power to be weighted toward mid to upper rev range. Guess work really! I found quite a few online runner length calculators and they all came back with roughly the same figure so i was happy enough. I also specc'd up some Jenvet itb's with 90mm trumpets and the length works out to be the same - spooky, but also gave me some confidence The runner must incorporate and velocity stack/trumpet to aid air flow in to the runner - another thing i had read and thought the original plenum could be improved on.
I measured up a few parts to and modelled in Google Sketchup:
This was mainly for me to send info/sizes to Mike - who was the man to produce final CAD drawings and fabrication.
As we didn't have an engine installed measuring up available space was hard work and was mainly done by guessing and looking at Mike's car for some datum points. We were designing this to fit our cup which comes with the relevant alternator mounting point. We also knew the rad would be an issue so thats why we had previously bought the Polo rad and also the bonnet pins so we could remove the slam panel.
The runner would fit (with a bit of work) but the plenum was a bit of a "fingers crossed and prey" excersize. I think i mocked the plenum up in cardboard to see if it would clear the bonnet. To be honest the least ammount of time went in to the plenum design. I did some research but time was getting a bit tight if we wanted this done before the car was to be mapped. I knew the volume of the original is around 3 litres and thought our could do with being a bit bigger. Not too much though as 1 - it needed to fit, and 2 - this isnt an ITB setup so the DBW throttle needs to be retained and throttle response might/would suffer. We also didnt botter tapering the plenum as i didnt know how to calc pressure drop/air speed and certainly didnt have access to any CFD software.
A few ideas were knocked back and forth then we settled on an "approved" design (drawn by Mike):
So, now on the the fabrication.....
...i will leave that bit to Mike as he made it happen
Thanks for reading
Right. before i write up the results of the rolling road day i need to rewind a few months! During the engine build process Mike and I thought we could have a go at making our own inlet manifold! We wanted to see if we cold improve on Renaults design and thought there was some extra potential to be released from our new engine. The idea all stemmed after a flow bench session earlier in the year where we primarily tested our cylinder head but progressed to bolting on the lower inlet followed by the upper plenum. The Upper plenum certainly reduced the cfm figures so that probably planted the seed in our heads - lets make our own
simple hey? err, no not really.....Some pics from the flow bench session (these have already appeared earlier on):
We then started to research what attributes of inlet design affect its performance and how inlets are tuned to suit engine characteristics. To be honet i spent ages reading various "tuning" guides on the Internet and at one point thought this is going to be too hard. I tried focussing on ideas from people with real experience rather than newbies like us
There are so many aspects of the design that can alter the result that it started to get a little overwhelming. Early on i even thought about modding the original plenum to improve flow; but a previous thread on here suggested it wasn't a great idea. We also looked at the Stone Automotive RS2 manifold for some guidance. I havent seen one of these in the flesh but the advert images certainly make it look like a very well produced package - one that does a great job of fitting in the engine bay whilst retaining the slam panel. As ours is mainly a track car (when its not broken) we could afford to make some extra space and remove the uneccessary parts - similar to the itb boys.One thing stood out regarding the design - Runner length! It was this measurement that i thought the RS2 came up a little short on - only to be expected since JMS designed it to be a bolt on/off application. I spent most of my time reading about how to calculate runner length depending on where you want to make the power (torque) in relation to the rev range. I also read how various engine characteristics change the values of the runner. Some of the measurements I used were - inlet cam duration, runner id (initially based around port size in cylinder head) and RPM of max torque. I'm sure others will know that more things need to be catered for, such as stroke, valve size, exhaust effieciency blah blah blah etc but i needed to start somewhere so just used the previously mentioned values. After all - i donnt pretend to know all there is to know about this but just wanted to have a go at making something that might offer an improvement.
Here is my "fag packet" calc sheet
In the end i opted for a total runner length (including head port) of 304mm, precisely - lol. Gut feeling was that our car is built to go round a track so might suit the power to be weighted toward mid to upper rev range. Guess work really! I found quite a few online runner length calculators and they all came back with roughly the same figure so i was happy enough. I also specc'd up some Jenvet itb's with 90mm trumpets and the length works out to be the same - spooky, but also gave me some confidence
The runner must incorporate and velocity stack/trumpet to aid air flow in to the runner - another thing i had read and thought the original plenum could be improved on.I measured up a few parts to and modelled in Google Sketchup:
This was mainly for me to send info/sizes to Mike - who was the man to produce final CAD drawings and fabrication.
As we didn't have an engine installed measuring up available space was hard work and was mainly done by guessing and looking at Mike's car for some datum points. We were designing this to fit our cup which comes with the relevant alternator mounting point. We also knew the rad would be an issue so thats why we had previously bought the Polo rad and also the bonnet pins so we could remove the slam panel.
The runner would fit (with a bit of work) but the plenum was a bit of a "fingers crossed and prey" excersize. I think i mocked the plenum up in cardboard to see if it would clear the bonnet. To be honest the least ammount of time went in to the plenum design. I did some research but time was getting a bit tight if we wanted this done before the car was to be mapped. I knew the volume of the original is around 3 litres and thought our could do with being a bit bigger. Not too much though as 1 - it needed to fit, and 2 - this isnt an ITB setup so the DBW throttle needs to be retained and throttle response might/would suffer. We also didnt botter tapering the plenum as i didnt know how to calc pressure drop/air speed and certainly didnt have access to any CFD software.
A few ideas were knocked back and forth then we settled on an "approved" design
(drawn by Mike):So, now on the the fabrication.....
...i will leave that bit to Mike as he made it happen
Thanks for reading
Nafoff
ClioSport Club Member
this is really interesting, very interested to see how this progresses....
talking of airboxes... "hi fred"
talking of airboxes... "hi fred"
Congratulations for trying something different!
I do recall seeing a JMS Manifold on a car (maybe a cup?) that was similar to this at a rolling road in Surrey.
It had runner extensions fitted to increase torque output and I believe the only part changed was the radiator fan but I only had a chance to glance at it.
I do recall seeing a JMS Manifold on a car (maybe a cup?) that was similar to this at a rolling road in Surrey.
It had runner extensions fitted to increase torque output and I believe the only part changed was the radiator fan but I only had a chance to glance at it.
Yeah that was mine, made 8lb/ft more torque and 4bhp extra without remapping to suit the extended runner length.
BMW 330ci sp/ 172Cup
Update #21 - Rolling Road
Bit of a strange one this, as i would ideally like to have documented the inlet build first, but hey ho I have a day off today so thought i might aswell write up the day at RS Tuning - Mike can write up the airbox build later on.
Originally (earlier in the week) we hoped to run the car up to RST with the original inlet on, get it roughly mapped to take a figure, swap to our new "CAM" (Cr33do And Meek) inlet and compare the results. Although we had trial fitted the CAM inlet in various guises the inlet was only 100% completed (off the car) at 1am on Wednesday! It felt like Fred's work ethic/shift patterns had rubbed off on me. I must stress at this point that Mike really pulled his finger out with this one - only 2 weeks ago fabrication hadn't really started!!
Anyway - luckily i have 1/2 a day off work on Wednesday so got cracking with a final test fit of the new inlet. I started at 1:30PM and by 2:30 i thought we could be in trouble! As you will read later on our inlet uses a Jenvey MR23 manifold bolted to the head. Doing up the lower 4 bolts on the head flange is a pain in the arse! My 3/8" drive bits were too big and 1/4" wouldnt reach. I had to dig out an allen key and do each bolt up 1/4 turn at a time - take into account the whole inlet and plenum was present, not just the stubby inlet! 1.5hrs later and the thing was bolted on tight. After that sesion i knew we couldnt afford the time to take it back off, replace the original, then swap over again whilst at RST. Dyno wouldnt allow for this and i didnt fancey doing it all again anyway.
The only other issue was that the injector connectors fouled on the runner back plate so i had to spin the injectors 180 degrees in the rail - not difficult. Also the silicone pipe that would form our induction kit didnt turn up in time! It still hasnt turned up! So we fashioned a s/s tube and flex hose as a temp (although quite effective) solution to get us running.
We fired it UP, no air leaks and took it for a quick test drive. All good so game on for Thursday at RST! During our test run we performed a low speed full throttle run in 2nd gear. Initially it didnt pull that well but as soon as 5k rmp came it went nuts and really pulled. It was that run that i came up with my guess of 200bhp - hardly scientific
So, Thursday came and Mike and I set off to RST; slightly nervous about what the day would bring. New engine, new inlet and lots of potential for a disaster! We arrived early and met Paul for the first time. Inital impressions were he is not one to mince his words! If he thinks something is crap he will tell you - no holding back. He was keen to see our new inlet and popped the bonnet - a few other gathered and not much was said apart from "is it air tight?" - hardly the ideal reaction :-S
The car was positioned in to the workshop
And then swiftly driven on to the rollers
We explained the spec of the engine at that it is pinking under anything other than a very light load - a sign of the engines (very) high compression. To recap - wosner 12.8cr pistons and head skimmed so much previously the cam belt required a larger pulley to gain tension!
Paul but a base map on the car a did an initial pull
The CAM inlet is suprisingly quiet (i was expecting something louder to be honest) but most importantly the engine had held together. Inital power 184bhp - Mike and I were dissapointed
Paul didn't seem overly optimitic about its potential power and said the inlet isnt doing much more than std at mid RPM but is improving higher up the rev range. At this point my previous hopes for big power were dashed and thoughts that we shouldn't have tried to make the inlet crossed my mind!
Time for a coffee and leave Paul to it...
...30-45mins later we venture back in to the dyno room and a new figure is on the screen....
.....194.3hp at 7k RPM - that's better! Mike and I were quite happy now. Even Paul was quite impressed with the figure and talked positively about the inlet He said that our car was out performing several cars that he had previously seen with short ATP boddies - and thought it was quite impressive for a single throttle car!
Final graph
Video of one of the many dyno runs - excuse the sound quality but i did have a wopping great fan blowing a huricane over my left shoulder!
Paul continued to tweak the map to gain extra power in other areas of the rev range but the "headline" figure would remain.
So why didnt we hit 200bhp (I know its "just" a figure"). Well the answer is this. Our engine is HIGH comp, very HIGH comp. Think somewhere between 13 and 14:1! The timing advance needed to be pulled right back to somewhere around 13-16 degrees, instead of the usual 27ish to avoid detonation. Excuse me if the figures sounds wrong - i did my best to remember everything.
You could tell Paul really wanted to get more from it (and he did at one point) but ultimatley the car needs to leave his workshop safe. It's really crying out for race fuel and then 200bhp would be on the cards. We also need to fix a minor airleak between the Jenvy and the head. Currently we are using a std gasket but this will be swapped for o-rings. We have already bought the long 1/42 extension to do that. Paul recommends a new set of plugs too - Megane Sport one NGKPFR7ZTG gapped to 0.7mm. Will run that past Fred. Maybe that will see us hit 195bhp
The drive home was mostly motorway so real world testing proved difficult. However, the car pull well from low down and comes on song the higher you rev it. Personally, i think the torque curve will work well on track and overall i think Mike and I are glad to have given inlet design a shot. After all, it's our track car and this type of stuff can sometimes be as interesting as flinging around the corners
Now researching methonal injection.....
Bit of a strange one this, as i would ideally like to have documented the inlet build first, but hey ho I have a day off today so thought i might aswell write up the day at RS Tuning - Mike can write up the airbox build later on.
Originally (earlier in the week) we hoped to run the car up to RST with the original inlet on, get it roughly mapped to take a figure, swap to our new "CAM" (Cr33do And Meek)
inlet and compare the results. Although we had trial fitted the CAM inlet in various guises the inlet was only 100% completed (off the car) at 1am on Wednesday! It felt like Fred's work ethic/shift patterns had rubbed off on me. I must stress at this point that Mike really pulled his finger out with this one - only 2 weeks ago fabrication hadn't really started!!Anyway - luckily i have 1/2 a day off work on Wednesday so got cracking with a final test fit of the new inlet. I started at 1:30PM and by 2:30 i thought we could be in trouble! As you will read later on our inlet uses a Jenvey MR23 manifold bolted to the head. Doing up the lower 4 bolts on the head flange is a pain in the arse! My 3/8" drive bits were too big and 1/4" wouldnt reach. I had to dig out an allen key and do each bolt up 1/4 turn at a time - take into account the whole inlet and plenum was present, not just the stubby inlet! 1.5hrs later and the thing was bolted on tight. After that sesion i knew we couldnt afford the time to take it back off, replace the original, then swap over again whilst at RST. Dyno wouldnt allow for this and i didnt fancey doing it all again anyway.
The only other issue was that the injector connectors fouled on the runner back plate so i had to spin the injectors 180 degrees in the rail - not difficult. Also the silicone pipe that would form our induction kit didnt turn up in time! It still hasnt turned up! So we fashioned a s/s tube and flex hose as a temp (although quite effective) solution to get us running.
We fired it UP, no air leaks and took it for a quick test drive. All good so game on for Thursday at RST! During our test run we performed a low speed full throttle run in 2nd gear. Initially it didnt pull that well but as soon as 5k rmp came it went nuts and really pulled. It was that run that i came up with my guess of 200bhp - hardly scientific
So, Thursday came and Mike and I set off to RST; slightly nervous about what the day would bring. New engine, new inlet and lots of potential for a disaster! We arrived early and met Paul for the first time. Inital impressions were he is not one to mince his words! If he thinks something is crap he will tell you - no holding back. He was keen to see our new inlet and popped the bonnet - a few other gathered and not much was said apart from "is it air tight?" - hardly the ideal reaction :-S
The car was positioned in to the workshop
And then swiftly driven on to the rollers
We explained the spec of the engine at that it is pinking under anything other than a very light load - a sign of the engines (very) high compression. To recap - wosner 12.8cr pistons and head skimmed so much previously the cam belt required a larger pulley to gain tension!
Paul but a base map on the car a did an initial pull
The CAM inlet is suprisingly quiet (i was expecting something louder to be honest) but most importantly the engine had held together. Inital power 184bhp - Mike and I were dissapointed
Paul didn't seem overly optimitic about its potential power and said the inlet isnt doing much more than std at mid RPM but is improving higher up the rev range. At this point my previous hopes for big power were dashed and thoughts that we shouldn't have tried to make the inlet crossed my mind!
Time for a coffee and leave Paul to it...
...30-45mins later we venture back in to the dyno room and a new figure is on the screen....
.....194.3hp at 7k RPM - that's better! Mike and I were quite happy now. Even Paul was quite impressed with the figure and talked positively about the inlet
He said that our car was out performing several cars that he had previously seen with short ATP boddies - and thought it was quite impressive for a single throttle car! Final graph
Video of one of the many dyno runs - excuse the sound quality but i did have a wopping great fan blowing a huricane over my left shoulder!
Paul continued to tweak the map to gain extra power in other areas of the rev range but the "headline" figure would remain.
So why didnt we hit 200bhp (I know its "just" a figure"). Well the answer is this. Our engine is HIGH comp, very HIGH comp. Think somewhere between 13 and 14:1! The timing advance needed to be pulled right back to somewhere around 13-16 degrees, instead of the usual 27ish to avoid detonation. Excuse me if the figures sounds wrong - i did my best to remember everything.
You could tell Paul really wanted to get more from it (and he did at one point) but ultimatley the car needs to leave his workshop safe. It's really crying out for race fuel and then 200bhp would be on the cards. We also need to fix a minor airleak between the Jenvy and the head. Currently we are using a std gasket but this will be swapped for o-rings. We have already bought the long 1/42 extension to do that. Paul recommends a new set of plugs too - Megane Sport one NGKPFR7ZTG gapped to 0.7mm. Will run that past Fred. Maybe that will see us hit 195bhp
The drive home was mostly motorway so real world testing proved difficult. However, the car pull well from low down and comes on song the higher you rev it. Personally, i think the torque curve will work well on track and overall i think Mike and I are glad to have given inlet design a shot. After all, it's our track car and this type of stuff can sometimes be as interesting as flinging around the corners
Now researching methonal injection.....
Last edited by a moderator:
Top marks for doing something different, but for all that time/hassle/money just to get 195bhp with high comp pistons/cams and a custom manifold it doesn't seem worth it.
As long as your happy with it though.
Nick
As long as your happy with it though.
Nick
BMW 330ci sp/ 172Cup
Hard not to agree with you Nick. The pistons were bought as the std ones were scrap (ours failed and so have others - poor casting) and it seemed crazy not to put some cams in whilst the engine was apart. The inlet was a "if we dont try it, we will never know" exercise and in reality cost is peanuts in cash (but lots of time). Just goes to show how hard it is to get power of these lumps.
Nick
BMW 330ci sp/ 172Cup
Figures. Not too bad but was hoping for a little more. especially when some people manage 203bhp from these cams and an induction kit?
Loads of pictures to follow. It's quite a nice bit of kit and is all detachable
But are those geting high figures on just cams and btcc air filters being tested on reliable independent rollers?
If it drives well and your happy with it then forget the figures.
BMW 330ci sp/ 172Cup
But are those geting high figures on just cams and btcc air filters being tested on reliable independent rollers?
If it drives well and your happy with it then forget the figures.
hehe
yes we are happy with the way it goes!
wow...love it, what a fantastic project. By all accounts thats some performance there mate.
I love the induction system
I love the induction system
RB 182
Can i do my biofuel conversion to it now? that should make it go faster
Potato fuel you say?
