Is it worth replacing the AFM to Plenum hose...
Discussion
....even if appears to be in a serviceable condition? Now that spring is more or less here (hope that doesn't jinx anything
) I want to start driving my Chim, but need to track down the rough running issues (which I mentioned on a thread a few months ago)
I saw a Scotty Kilmer Video (Youtuber) about how replacing the AFM pipe on a lot of cars is worth doing as of course if unmetered air gets into the intake after the AFM, it causes havoc with the running (obvs). This pipe is susceptible to leaks because it connects the body of the car to the engine, so it's always moving and when the rubber is old and gets brittle, well, it's fairly obvious what can happen.
I've inspected mine and it's appears fine - has anyone else replaced theirs and noticed an improvement in running? I'm talking about the 90 degree pipe after the AFM...
) I want to start driving my Chim, but need to track down the rough running issues (which I mentioned on a thread a few months ago) I saw a Scotty Kilmer Video (Youtuber) about how replacing the AFM pipe on a lot of cars is worth doing as of course if unmetered air gets into the intake after the AFM, it causes havoc with the running (obvs). This pipe is susceptible to leaks because it connects the body of the car to the engine, so it's always moving and when the rubber is old and gets brittle, well, it's fairly obvious what can happen.
I've inspected mine and it's appears fine - has anyone else replaced theirs and noticed an improvement in running? I'm talking about the 90 degree pipe after the AFM...
Personally, the factory used an inappropriate product in the flexi hosing. It is susceptible to heat gain from the manifoled below and from deformation. Plus the discussion of the rough profile of the internal surfaces and air flow.
Given that any original item is now a couple of decades old, then replacement could be seen as renewing a consumable.
The elbow sections being sold have different I.D. to match up with the plenum and the AFM (which are different) coupled with the low volume then they are expensive.
On my 350i - yes I know it isn't a Chimp - I used an alloy elbow (which I trimmed to fit) with a matching OD of the plenum, a silicone 45' to connect to the plenum and a straight silicone reducer to connect to the 'AFM'. Used decent worm drive clips to hold together. Then wrapped it in exhaust wrap. All of which was, installed, about 2/3 the price of the dedicated silicone elbow alone.
It isn't going to do any harm swapping out the flexible for a rigid set up. Indeed, the silicone elbow looks, IMHO, more 'factory' than the mess TVR installed. Not sure it'll fully cure any rough running. This could be teo things or twenty.
Given that any original item is now a couple of decades old, then replacement could be seen as renewing a consumable.
The elbow sections being sold have different I.D. to match up with the plenum and the AFM (which are different) coupled with the low volume then they are expensive.
On my 350i - yes I know it isn't a Chimp - I used an alloy elbow (which I trimmed to fit) with a matching OD of the plenum, a silicone 45' to connect to the plenum and a straight silicone reducer to connect to the 'AFM'. Used decent worm drive clips to hold together. Then wrapped it in exhaust wrap. All of which was, installed, about 2/3 the price of the dedicated silicone elbow alone.
It isn't going to do any harm swapping out the flexible for a rigid set up. Indeed, the silicone elbow looks, IMHO, more 'factory' than the mess TVR installed. Not sure it'll fully cure any rough running. This could be teo things or twenty.
I changed mine for the ACT smooth kit, but mainly because the tumbledryer tube was wearing through on its steel coil.
I have noticed several horses since I installed it.
The other thing I had to do was create a bracket from a piece of aluminium to hang the connecting tube from the top of the nose cavity - because the ACT hoses position the filter almost at the top, rather than at the bottom.
Easy enough to do, and the intake is not quite as low to the ground now either.
I have noticed several horses since I installed it.
The other thing I had to do was create a bracket from a piece of aluminium to hang the connecting tube from the top of the nose cavity - because the ACT hoses position the filter almost at the top, rather than at the bottom.
Easy enough to do, and the intake is not quite as low to the ground now either.
Edited by PabloGee on Tuesday 4th March 14:33
Thanks for the replies people. PabloGee I always thought the idea was to have the air filter as low as possible due to the air being colder (and therefore more dense) the nearer to the road surface you get. Having a few extra bhp would be nice, but I'm not really interested in speed anymore (well, maybe occasionally 
) I would never go around picking fights in my chim, which despite being a 450 would certainly be matched by a decent hot hatch these days.
I just want to get the thing running right and thought I'd try the easy things first - it's idles ok when it's cold, but when hot it will stall at 60mph changing up from 3rd to 4th - that's why I thought I've got the mother of all intake leaks.
) I would never go around picking fights in my chim, which despite being a 450 would certainly be matched by a decent hot hatch these days.I just want to get the thing running right and thought I'd try the easy things first - it's idles ok when it's cold, but when hot it will stall at 60mph changing up from 3rd to 4th - that's why I thought I've got the mother of all intake leaks.
I'd be surprised if the height change of 6 inches would make much difference to our cars.
I would have left it where it was if the ACT hoses arrived there, but they don't.
Kind of makes sense to lift it up in the later nose, that said, I'm not sure how effective the grill is at stopping water at speed, but it does seem to prevent the majority of water running down off the bonnet when washing the car.
I would have left it where it was if the ACT hoses arrived there, but they don't.
Kind of makes sense to lift it up in the later nose, that said, I'm not sure how effective the grill is at stopping water at speed, but it does seem to prevent the majority of water running down off the bonnet when washing the car.
PabloGee said:
I changed mine for the ACT smooth kit, but mainly because the tumbledryer tube was wearing through on its steel coil.
I have noticed several horses since I installed it.
May I ask how you have noticed the extra horses? Dyno, or placebo? Those mods will help other work in increasing power but not stand alone that anyone would notice. I don't wish to start an arguement more just wanting to see people get an honest and balanced view. I have noticed several horses since I installed it.
I fitted the full smooth bore kit. The air filter can not be seen through the grill. It stops it getting soaked in water.
The early TVRs had the air filter in the hot engine bay.
I have been riding motor bikes for 53 years. Most of them through the seat of my pants.
Now my pants are really smart arses & can tell me if things are running OK. These pants can't be bought on line they grow on you with age & feeling.
So no dyno before or after needed. I could feel the car breathing a lot easier & pulling better.
Probably no HP gain but it ran better , smoother & pulled better.
So my pants say smooth bore is the way to go.
The early TVRs had the air filter in the hot engine bay.
I have been riding motor bikes for 53 years. Most of them through the seat of my pants.
Now my pants are really smart arses & can tell me if things are running OK. These pants can't be bought on line they grow on you with age & feeling.
So no dyno before or after needed. I could feel the car breathing a lot easier & pulling better.
Probably no HP gain but it ran better , smoother & pulled better.
So my pants say smooth bore is the way to go.
You can just buy some silicone hoses and do it yourself, may not look quite as pretty at the filter end but you can't see it anyway.
To be fair the Act kit is nice, would be good if they just sold it as a complete one with the elbow included.
You can buy "I have a smooth bore elbow" T Shirts.
To be fair the Act kit is nice, would be good if they just sold it as a complete one with the elbow included.
You can buy "I have a smooth bore elbow" T Shirts.
I looked into building my own version with silicone hose sections - unfortunately you're dealing with some unusual twists and turns, which will be very difficult to execute. Even the plenum elbow requires different inner diameters at either end.
I would heartily recommend the ACT kit, because it is shaped exactly to fit the car, with only one join at the nose - a join that makes absolute sense.
I still needed to trim the kit down a little around the AFM, but that's to be expected - the technique is to fit the jubilee clip and cut to it with a new stanley blade.
I would heartily recommend the ACT kit, because it is shaped exactly to fit the car, with only one join at the nose - a join that makes absolute sense.
I still needed to trim the kit down a little around the AFM, but that's to be expected - the technique is to fit the jubilee clip and cut to it with a new stanley blade.
I’d agree with Fred’s assessment.
The ACT kit is excellent and a very worthwhile upgrade especially if you get rid of the AFM and install a modern Ecu system so you have a continuous wide smooth bore line incorporating a smooth bore elbow all the way to the butterfly.
I’d also agree it won’t add top end BHP very much but everywhere else it helps the engine breath so giving a more urgent sense of power.
Two things I noticed was this gives more induction roar and when cruising my throttle setting was next to non existent. Like I was barely touching the throttle for the same cruising speed.
I’d installed the ACT set up before the Ecu change so both these effects were more noticeable after the Ecu went in. My car was then mapped with the ACT set up so could just be the effect of the Ecu but I think both play there part. Just much more efficient. The main thing the ACT set up improves is the flow of air from the filter through the wing which is very poor using the old pipe work. It has less bends and takes a more direct line.
At cruising speeds my car was better on fuel which you would expect given the level of upgrade the car now possessed.
The ACT kit is excellent and a very worthwhile upgrade especially if you get rid of the AFM and install a modern Ecu system so you have a continuous wide smooth bore line incorporating a smooth bore elbow all the way to the butterfly.
I’d also agree it won’t add top end BHP very much but everywhere else it helps the engine breath so giving a more urgent sense of power.
Two things I noticed was this gives more induction roar and when cruising my throttle setting was next to non existent. Like I was barely touching the throttle for the same cruising speed.
I’d installed the ACT set up before the Ecu change so both these effects were more noticeable after the Ecu went in. My car was then mapped with the ACT set up so could just be the effect of the Ecu but I think both play there part. Just much more efficient. The main thing the ACT set up improves is the flow of air from the filter through the wing which is very poor using the old pipe work. It has less bends and takes a more direct line.
At cruising speeds my car was better on fuel which you would expect given the level of upgrade the car now possessed.
Edited by BritishTvr450 on Thursday 6th March 09:27
PabloGee said:
Typically in fields.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
definately better than the original vacuum hose stuff and was one of the first things I changed, then it all got out of hand and I couldn't stop.
macdeb said:
PabloGee said:
Typically in fields.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
definately better than the original vacuum hose stuff and was one of the first things I changed, then it all got out of hand and I couldn't stop. typical ex super biker 
Sardonicus said:
macdeb said:
PabloGee said:
Typically in fields.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
definately better than the original vacuum hose stuff and was one of the first things I changed, then it all got out of hand and I couldn't stop. typical ex super biker hello bloke, long time no see. Hope you well.
macdeb said:
Sardonicus said:
macdeb said:
PabloGee said:
Typically in fields.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
definately better than the original vacuum hose stuff and was one of the first things I changed, then it all got out of hand and I couldn't stop. typical ex super biker hello bloke, long time no see. Hope you well. hope your good too 
Sardonicus said:
macdeb said:
Sardonicus said:
macdeb said:
PabloGee said:
Typically in fields.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
Absolutely no difference whatsoever to the car, it is simply a much smarter and more robust fitting than the old stuff.
definately better than the original vacuum hose stuff and was one of the first things I changed, then it all got out of hand and I couldn't stop. typical ex super biker hello bloke, long time no see. Hope you well. hope your good too Gassing Station | Chimaera | Top of Page | What's New | My Stuff