Cheapo inlet mod..

[ChrisGB]

Hi to All

First mod to the MR2 today. I have been considering the inlet pipe as a possible for modification. I was going to lay up a glassfibre pipe round a soft moud to fit, but being time poor, I decided a first attempt to test the waters would be in order. Using a length of Flexflyte 3" tempreature resistant flexible spring steel coil supported ducting and 2 jubilee clips, the modification was completed in around 10 minutes.

The results are quite noticable. Throttle response at low revs seems to be improved. Running up into the midrange, the car always felt a little weak at around the 4000 rpm mark, not a flat spot, but not the expected pull either. The mod has sorted this and the car now seems noticably stronger from 3500 to 5000 rpm with a decent swell of torque across this band where it used to feel flat. At the top end there is little in it, a small improvement.

Noise wise there is no noticable effect most of the time. The only really noticable effect is at around the 4000rpm mark at full throttle, but it is subtle, just a little louder and deeper.

So improved midrange / upper midrange is the key benefit. Worth a tenner most definately.

Chris

[Anonymous]

Try re-setting your ECU, if you have not already done so, it will re-learn using your improved air flow.

Rob

[ChrisGB]

Try re-setting your ECU, if you have not already done so, it will re-learn using your improved air flow.

Rob

Hi Rob

I have been out giving it some stick for an hour or two this evening and it has now strengthened up at the top end a bit more (as the ECU learns the new airflow possibly). The car now pulls noticably better up to 6500rpm and has a considerably improved midrange. The car originally always felt a bit like it was holding back around 4000 rpm (maybe 3750 to 4500) like the torque curve had a level bit or slight drop  or two in that region, then it used to pick up well from there. Now there is a natural feeling torque delivery that has a slightly noticable step up at around 4300 / 4700 rpm and then good clean pull all the way through the upper rev range.

I cannot put a figure to it, but there is definately more torque. I just got back from one of my favourite test routes and the speeds at the ends of the straights were quite a bit higher. Dont think BHP is up much, if any, but drivability is definately better.

Thinking about how this works, the original inlet had a restriction that was easily bigger than the inlet valve area, so was not acting to restrict the mass of air flow as such. I suspect that it is in there to reduce the induction noise by reducing the intensity of the inlet pulses. Unfortunately, this will also slightly reduce the effectiveness of said pulses and thus reduce cylinder filling at certain engine speeds. This would be an obvious cause for the slightly unnatural feeling delivery of the standard setup.  Driving the car with the roof up tonight, there was definately a bit more noise once in the 3500 rpm + region, so this would make sense. Still reckon it is the most effective £10 spent (tube and two stainless steel jubilee clips) and 10 mins fitting that I have ever seen.

If the TRD pipe achieved the same results it would be worth the nearly £150 asking price IMO.

Chris

[markiii]

or you could just buy one of mine for a third of teh cost   s:wink: :wink: s:wink:

[northernalex]

" Flexflyte 3" tempreature resistant flexible spring steel coil supported ducting and 2 jubilee clips" where did you get this from, might be a cheap alternative to the Markiii pipe (id love a markiii pipe but cant justify getting one as I will prolly be gettting a PPE intake or SP kit later on)


Alex  s:) s:)

[ChrisGB]

" Flexflyte 3" tempreature resistant flexible spring steel coil supported ducting and 2 jubilee clips" where did you get this from, might be a cheap alternative to the Markiii pipe (id love a markiii pipe but cant justify getting one as I will prolly be gettting a PPE intake or SP kit later on)


Alex  s:) s:)

Hi Alex

Bought mine from Anglia Hose and Hydraulics near Colchester in Essex but I am sure you can buy it local to where you are. If not 01206 212168 is their phone number. They sell it by the M.

Chris

[Anonymous]

Anychance of some photos? this sounds like a mod I can start off with (well after I paint the calipers!!)

[ChrisGB]

Anychance of some photos? this sounds like a mod I can start off with (well after I paint the calipers!!)

Will try and do some tomorrow if I get up early enough to fit them in before I go out. If you can locate the restriction in the inlet duct just under the nearside tail light, imagine it replaced with a length of spiral wire ducting. The ducting has to be cut to go over the ends of the airbox and pipe coming from over the wheel arch. It really is a simple to do mod.

Remove two bolts holding tail light assembly, unclip loom from tailight assembly, remove cluster remembering not to break off the lower location tab which is situated toward the left side of the cluster down low (you need to pull the cluster out to the rear a little at an angle then toward the middle of the car to release the lower tab) and rest light cluster out of the way.

One screw holds the original restrictor, located just beneath the coolant resevoir. I got a posidrive in there without needing to remove the coolant bottle. Also worth loosening the screw holding the duct at its rearmost point. Wriggle the original duct about until you can get it out. Cut new ducting to appropriate length. Cut slots in airbox end to clear webbing on airbox inlet if you want it to look nicer. Jubilee clip airbox end on, jubilee clip duct end on. Replace light, remembering to re clip loom.

Job took 10 mins tops. Easy to reverse it if you dont like the effect. I will invest in a proper replacement son, but used this to see how it was likely to perform.

Chris

[ChrisGB]

Anychance of some photos? this sounds like a mod I can start off with (well after I paint the calipers!!)

Photos as requested:

Apologies for the photographic quality. Trying to get decent shots of black things in shadows takes more time than I have this morning!

Hope these help.

Chris

[leon_in_uk]

thanks for posting the pics...

i had an air feed when i had my pipercross. just brough a metal flexi tube, similar to that, for about £6..

it does the effect, but surly this does the same as the markiii pipe, wouldnt it???

[Anonymous]

looks good - think I'll have a go at this.

I was just going to up and buy a markiii pipe myself but it appears from the fitting guide thread that the latest version is liable to crack your airbox...(sorry markiii don't flame me - not knocking your efforts here but that really is the lasting impression that fitting thread gives )

[northernalex]

it does the effect, but surly this does the same as the markiii pipe, wouldnt it???

I would expect it would, and the air flow would be more turbulant, however it wil get hot quicker than the markiii polished pipes.  Far cheaper though.

Someone who knows more care to comment?

[ChrisGB]

it does the effect, but surly this does the same as the markiii pipe, wouldnt it???

I would expect it would, and the air flow would be more turbulant, however it wil get hot quicker than the markiii polished pipes.  Far cheaper though.

Someone who knows more care to comment?

From the top:

Turbulence: the original and replacement pipes fit inside the airbox and wheelarch duct, this fits outside. This means there are two small steps on the inside of the system where the pipe leaves the duct and where it enters the airbox. Both will cause some turbulance near the surface of the pipes. The spiral wound duct pipe has an almost smooth inner surface, so no effect of any importance there.

I think this mod works on two levels, firstly by removing a restriction in the inlet duct, it allows a little more air to flow if the engine demands it, but secondly and IMO a bigger effect is on the waves passing between valve backs and inlet duct end in the intake system. The restrictor seems to have been designed to partially decouple the inlet from atmoshpere by reducing the intensity of these waves (which form the basis of any inlet system tuning). Removing it results in a bit more noise, but more effective  pulse enhanced induction. In this respect the turbulance is largely irrelevant. Given the valve curtain area is certainly much smaller than the 7.1 square inches that the inlet pipe CSA gives and it is a safe bet that a little turbulance will be very unlikely to affect air flow in any measurable way.

Heat soak:

The pipe section is continually cooled by the air passing through it. The pipe will get warm, however its thin rubberised fabric walls will hold very little heat. This means they will get warm quickly if the car is stood at the lights. However, the same thin rubbrised fabric walls will have a much smaller specific heat capacity and will have a very poor heat conductivity, so the air flowing through the pipe will not be heated by any noticable amount.

A metal pipe will take longer to warm up, but will transmit heat well, so may cause a greater warming effect if the car is stood heat soaking for a while. Also it will hold more heat energy, so will cause heating of the intake air for longer. In all cases (metal, plastic or flexipipe), the effects will be nigligable as the short length, small air contact area and high airflow will combine to render any heating effect undetectable on a dyno IMO.

On the downside, this is a temporary mod. The pipe is rated to 150deg C. The car underbonnet area will get very warm in that area when one switches off on a still day, with heat from the exhaust system soaking the area, so I am sure that it will perish or dry out and crack eventually, I will need to keep an eye on it. Also, it is routed around any other pipes, but may be just in contact with an unfinished pressing edge just where it joins the wheelarch duct, so may well cut through. Need to monitor this as well. The jubilee clips have no lips on the mouldings to grip, so there is also a good chance that the pipe will come off at some stage although we had a good high speed thrash for 180 miles today and a couple of hundred fast miles over last week with no problems.

So yes there are more elegant and permanent solutions, but this seems to work well as a stopgap. It proves what I wanted to check, namely that fitting a proper pipe would be worth spending money on.

I too was concerned about the fit of the markiii pipe in the airbox, so I will be using the original for measurements and hand laying a very light weight cotton / epoxy version around a wax mandrel. May even lay in the mounting lug.

Chris

[Anonymous]

I have been reading your posts and am impressed with the knowledge shown on this subject so thought i'd pose my question: I have a Blitz power SUS induction kit fitted to my car and, ever since fitting it, have been concerned about the amount of cold air that the filter itself is recieving. I still have the 1st stage of the inlet system (the one from the left vent to the rear of the light cluster). but there it stops and there is a gap of about 8 - 10" (where the airbox used to be) before the filter begins. Can anyone (preferably) supply a pipe and clips to help get a more direct feed or just point me in the direction of a helpful shop? Also, the filter itself is located worryingly close to the manifold and i'm concerned about heat soak from it... Any suggestions would be highly appreciated! (especially if someone can supply a shield, homemade or not, for a respectable price!)

[ChrisGB]

I have been reading your posts and am impressed with the knowledge shown on this subject so thought i'd pose my question: I have a Blitz power SUS induction kit fitted to my car and, ever since fitting it, have been concerned about the amount of cold air that the filter itself is recieving. I still have the 1st stage of the inlet system (the one from the left vent to the rear of the light cluster). but there it stops and there is a gap of about 8 - 10" (where the airbox used to be) before the filter begins. Can anyone (preferably) supply a pipe and clips to help get a more direct feed or just point me in the direction of a helpful shop? Also, the filter itself is located worryingly close to the manifold and i'm concerned about heat soak from it... Any suggestions would be highly appreciated! (especially if someone can supply a shield, homemade or not, for a respectable price!)

Hi Sean

I have no idea what the air temps would be in that area, but cannot see Toyota adding the expense of a duct system if the air there was at useful temperature. I have never seen an inductionkit produce an improvement in power myself in any car, apart from one special where the cone filter was in the scuttle tray, not under the bonnet.How did the performance change when you fitted the kit? If the air is cool enough, there should be no negative effects, but doing it this way, you know the air is taken from just inside the wing vent. Pesronally, I would be tempted to go back to stock airbox and inlet pipe mod and try measuring a few increments with a stopwatch or use your favourite roads for a little objective perfomance testing to see how the perfomance is affected. I have a bit of local road I know well and know just how fast I will be going at certain points. This gives a good indication of any performance benefits. This mod works, Shell V Power works, ECU reset works and the car is running really very well now.

Chris

[Anonymous]

cheers for the info chris, i'm a bit loathed to remove the kit as i made a point of gettin an expensive kit (and hopefully a good one!) as for performance differences, Ive noticed a marked increase in 'umph' once the car reaches 4000rpm (which i spend most of my time above!) and as for below, i havent really made a point of checking it as, like i say, if i want to go fast, im usually above 4000rpm in most of the gears. I'm just looking for a way of ensuring im getting direct cold air fed against the cone, and stopping the hot manifold air getting to it. From your previous pictures, chris, it looks to me like a slightly longer version of the exact setup you have would suit my needs perfectly

[ChrisGB]

cheers for the info chris, i'm a bit loathed to remove the kit as i made a point of gettin an expensive kit (and hopefully a good one!) as for performance differences, Ive noticed a marked increase in 'umph' once the car reaches 4000rpm (which i spend most of my time above!) and as for below, i havent really made a point of checking it as, like i say, if i want to go fast, I'm usually above 4000rpm in most of the gears. I'm just looking for a way of ensuring I'm getting direct cold air fed against the cone, and stopping the hot manifold air getting to it. From your previous pictures, chris, it looks to me like a slightly longer version of the exact setup you have would suit my needs perfectly

Hi Sean

Ideally, you want to make sure there are no gaps in the system between cone and wing vent, that way the engine will draw cool air in from the wing vent area. I take it the cone is an open on all sides one? This would mean mking a sealed box around it and linking this to the ducting.

Sound like removing the elbow, whatever you replace it with, makes a significant improvement.

Chris

[Anonymous]

the cone is open on all sides yes, do you have any suggestions on where to locate some suitable pipe to connect to the wing inlet pipe? and i've got absolutely no idea how i would go about finding a box to enclose the cone! never mind fitting it... any ideas?

[Anonymous]

Chris, you could ahve saved yourself some effort through some judicious usage of the search facility. Both the mod you have just engineered and testing to assess the performance increase due to the fitment of the inlet pipe are well documented. Respect for having a crack and getting stuck in but part of me can't help thinking that you're reinventing the wheel - a bit  s:? :? s:?

[ChrisGB]

Chris, you could ahve saved yourself some effort through some judicious usage of the search facility. Both the mod you have just engineered and testing to assess the performance increase due to the fitment of the inlet pipe are well documented. Respect for having a crack and getting stuck in but part of me can't help thinking that you're reinventing the wheel - a bit  s:? :? s:?

Hi Rusty

I did plenty of reading up before messing with the inlet. I have not re invented the wheel, but have perhaps made something a little more comprehensive than the search facility turned up. No threads turned up in the searches were particularly informative. Snippets of information dotted around over several threads. Trawling through them all it seemed like a good idea to post a how to and an assessment of the results all in one place. There are a few threads with some info on replacing the elbow, but none when I origianlly posted, that  gave much information on what the differences in drivability and perfomance were. Also struck me that the two alternatives most referred to were not a good idea. The TRD item at silly money or the MKIII with too tight a fit in the airbox.

I did the photos as someone asked for them. It seems like an ultra simple mod if you have spent much time underbonnet and are experienced, but we have to remember that many dont know too much about what goes on around the hot noisy bit, so the photos I felt were useful.

As long as it helped someone, I am happy to have spent time posting the details.

Chris

[markiii]

the MKIII with too tight a fit in the airbox.

a minor glitch fixed 12 months ago   s:D s:D

[ChrisGB]

the MKIII with too tight a fit in the airbox.

a minor glitch fixed 12 months ago   s:D s:D

But I did not know it reading the inlet mod threads (until now that is). May well treat myself to one when the weather warms up a bit.

Chris

[Anonymous]

Chris,

Some of these might have been hard to find, just thought they might be of use to you:

http://www.mr2roc.org/phpBB2/viewtopic.php?t=4062&highlight=pmd

and

http://www.mr2roc.org/phpBB2/viewtopic.php?t=6296&highlight=

The second link is off on a bit of a tangent but I thought it might be of interest!

[Anonymous]

am looking at doing a similar sort of thing, but with the added advantage of the veilside wide body kit having bigger/wider vents (hopefully more air flow)

I've come to the conclusion that if you are using an aftermarket (exposed) filter, the air flow through the stock cloth pipe will be minimal.  This I believe is because the stock system being sealed, will actually suck that cold air from behind the battery, if you've opened up the system then there just wont be any sucking anymore (ooh eerr)

Its even possible in principle/theory, that the air passing the hole behind the battery, if travelling at any speed (from the vent) could infact do the opposite   s:? :? s:?  

i'm going to try and run my filter to near the fuel filler, using flexi pipe that is smooth on the inside (ribbed outside), this way with the filter being sealed all the way to the trubo it should in theory suck cold air from there?

if not, at least it will be better than sitting behind the light and nearer to the heat of the exhaust?

I think that makes sense ?   s:lol: :lol: s:lol:

[loadswine]

Cold air is good if you can get it. Sounds good, waiting to see what you fab up this time!