Plenum and Intake Mods
Discussion
Hi all. 
At the moment I'm currently replacing the valley gasket as it has developed a small leak, and I thought I'd ask for opinions on any 'subtle' mods that can be done as the plenum and intake manifold are off.
My options/thoughts were, an insulator of sorts, a plenum packer/spacer, shorten the trumpets (by how much
?), remove trumpets, or remove trumpets and blend the base!
So what would you do
?
At the moment I'm currently replacing the valley gasket as it has developed a small leak, and I thought I'd ask for opinions on any 'subtle' mods that can be done as the plenum and intake manifold are off.
My options/thoughts were, an insulator of sorts, a plenum packer/spacer, shorten the trumpets (by how much
?), remove trumpets, or remove trumpets and blend the base!So what would you do
?Magna Parva insulator (they still had five or six of them when I got mine a couple of months ago),. ca. 40 quid; blend the trumpet base, and get a silicone air mass meter - TB elbow. That lot should provide the best bang for bucks.
If you can wait a little (not bl00dy likely with this weather
) or have a plenum going spare, you could also have the TB bored out and a bigger throttle plate fitted. Eliot @mez.co.uk does that job for not a lot of money (£105ish plus shipping etc IIRC) and very nicely, too IMO. This will probably necessitate a fuel injection remap, though.
If you can wait a little (not bl00dy likely with this weather
) or have a plenum going spare, you could also have the TB bored out and a bigger throttle plate fitted. Eliot @mez.co.uk does that job for not a lot of money (£105ish plus shipping etc IIRC) and very nicely, too IMO. This will probably necessitate a fuel injection remap, though.That looks like a 500 set-up in which case the trumpets are already shortened over the Rover length and probably shouldn't be cut down any more.
The SC power chaps sell some bell mouths which fit but I've not seen any test results for the effect.
One of the best things you can do is make sure the new gasket fits the ports correctly ( most do not and need fettling) and ensure the manifold lines up to the port as well. (engineers blues is the stuff to use)
The manifold can be slightly improved on a couple of the ports there's a few sharp turns / edges which can be smoothed off but don't go mad its not the thickest of parts
Matt
The SC power chaps sell some bell mouths which fit but I've not seen any test results for the effect.
One of the best things you can do is make sure the new gasket fits the ports correctly ( most do not and need fettling) and ensure the manifold lines up to the port as well. (engineers blues is the stuff to use)
The manifold can be slightly improved on a couple of the ports there's a few sharp turns / edges which can be smoothed off but don't go mad its not the thickest of parts
Matt
just fitted a thermal plenum spacer plate from tvr power,also whilst it was off,polished up all the inside's of the trumpets(was thinking of shortening them but need to read more into it)fitted a silicone elbow from plenum to afm,and straight silicone hose from afm to filter,it has made it a completly different car to drive,throttle response is infinatly better,it seems a hell of a lot quicker too throughout the whole rev range.for the cost of a few hours work in the garage and the silcone hose's(£68)it is probably the best thing(and cheapest)i've done to mine so far!!
Before you think of going blended base, have a look at my post at the bottom of this page:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I would stick some flared trumpets on there rather than blend the base... Not sure if the heat insulators make any noticeable difference but the enlarged throttle's are good from Eliot. Though to make the most of this you'll want to get a bigger air flow meter!
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
I would stick some flared trumpets on there rather than blend the base... Not sure if the heat insulators make any noticeable difference but the enlarged throttle's are good from Eliot. Though to make the most of this you'll want to get a bigger air flow meter!
Thanks for the input so far guys. 
So as it stands at the mo, on the more basic stuff we've had, use an insulator/don't use an insulator, blend the base/don't blend the base and use trumpets, and smooth elbow.
As Matt's pointed out it's a 500 setup, 36000 mile'er with everything standard except the Precats are out, and a sleeved box.
I'm not looking at chasing big numbers or replacing the ECU in the future, so was just planning on making some subtle tweeks while the cars apart that would provide some benefit without having to go down the route of remaps.
So far the only item on order is the smooth elbow from ACT, and 'was' thinking of an insulator, which seems to make sense, but was just curious if going to the hastle of blending the base on a standard car would be worth it, as I realise that you wouldn't get the most out of it without a remap/ECU change.
So as it stands at the mo, on the more basic stuff we've had, use an insulator/don't use an insulator, blend the base/don't blend the base and use trumpets, and smooth elbow.
As Matt's pointed out it's a 500 setup, 36000 mile'er with everything standard except the Precats are out, and a sleeved box.
I'm not looking at chasing big numbers or replacing the ECU in the future, so was just planning on making some subtle tweeks while the cars apart that would provide some benefit without having to go down the route of remaps.
So far the only item on order is the smooth elbow from ACT, and 'was' thinking of an insulator, which seems to make sense, but was just curious if going to the hastle of blending the base on a standard car would be worth it, as I realise that you wouldn't get the most out of it without a remap/ECU change.
Crazycraig said:
Thanks for the input so far guys.
So as it stands at the mo, on the more basic stuff we've had, use an insulator/don't use an insulator, blend the base/don't blend the base and use trumpets, and smooth elbow.
As Matt's pointed out it's a 500 setup, 36000 mile'er with everything standard except the Precats are out, and a sleeved box.
I'm not looking at chasing big numbers or replacing the ECU in the future, so was just planning on making some subtle tweeks while the cars apart that would provide some benefit without having to go down the route of remaps.
So far the only item on order is the smooth elbow from ACT, and 'was' thinking of an insulator, which seems to make sense, but was just curious if going to the hastle of blending the base on a standard car would be worth it, as I realise that you wouldn't get the most out of it without a remap/ECU change.
If you don't mind wielding the dremel for about 8-10 hours, I'd say blending the base would still give the best bang for bucks in combination with the plenum insulator. Sure, you may get a bit more torque under the power curve with the trumpets (or you may dont depnding on who to believeSo as it stands at the mo, on the more basic stuff we've had, use an insulator/don't use an insulator, blend the base/don't blend the base and use trumpets, and smooth elbow.
As Matt's pointed out it's a 500 setup, 36000 mile'er with everything standard except the Precats are out, and a sleeved box.
I'm not looking at chasing big numbers or replacing the ECU in the future, so was just planning on making some subtle tweeks while the cars apart that would provide some benefit without having to go down the route of remaps.
So far the only item on order is the smooth elbow from ACT, and 'was' thinking of an insulator, which seems to make sense, but was just curious if going to the hastle of blending the base on a standard car would be worth it, as I realise that you wouldn't get the most out of it without a remap/ECU change.
) but as you've got a 5 litre you're not exactly short on torque around the 4-4.5K mark anyway, compared to the rather modest top end power it's making, and for your investment of just about £0 you can't beat it. If however, you have got a life (unlike yours truly) and your time is worth more than the £250-300 for the trumpets, it makes sense to go with the latter.
Ive been down this route and in the end went for an ACT induction kit, Super flare trumpets, (I tried shortening the originals but made a pigs ear of it. I made an insulator plate from Tufnol carp grade, cost £7 for 2 sheets and onlt used 1. took about 2 hours to make and fit it with nothing more than a drill and a jig saw, More than happy with the results, plenty of pull right through the rev range and the insulator keeps the plenum cool enough to lean on without burning your hand. I already had the plenum off for powder coating otherwise I might never have got round to doing it but im glad i did.
I'm waiting for trumpets and smooth bore kit from Act, I'm wondering where I can get an insulator plate? I don't have a jig saw, so unless the material is very easy to cut I'm not going to be able to do it myself.
I'm guessing the benefit is cooler fuel entering the combustion chambers?
Thanks
I'm guessing the benefit is cooler fuel entering the combustion chambers?
Thanks
The maker of the insulator plates is at www.magnaparva.com (you can order one subject to availability and get an ivoice per email to be paid using PayPal - works quite well).
The benefit is indeed cooler intake air as there now is a heat barrier between the hot engine parts and the plenum - Magna Parva in their documentation reckons that the resulting 10-15 degrees C difference in intake air temps on plastic-bodied cars means the ignition can be advanced by 2-3 degrees, which means extra power and efficiency comes from two sides.
The benefit is indeed cooler intake air as there now is a heat barrier between the hot engine parts and the plenum - Magna Parva in their documentation reckons that the resulting 10-15 degrees C difference in intake air temps on plastic-bodied cars means the ignition can be advanced by 2-3 degrees, which means extra power and efficiency comes from two sides.
900T-R said:
The maker of the insulator plates is at www.magnaparva.com (you can order one subject to availability and get an ivoice per email to be paid using PayPal - works quite well).
The benefit is indeed cooler intake air as there now is a heat barrier between the hot engine parts and the plenum - Magna Parva in their documentation reckons that the resulting 10-15 degrees C difference in intake air temps on plastic-bodied cars means the ignition can be advanced by 2-3 degrees, which means extra power and efficiency comes from two sides.
So should I be looking at advancing my ignition, if so how do I do it.The benefit is indeed cooler intake air as there now is a heat barrier between the hot engine parts and the plenum - Magna Parva in their documentation reckons that the resulting 10-15 degrees C difference in intake air temps on plastic-bodied cars means the ignition can be advanced by 2-3 degrees, which means extra power and efficiency comes from two sides.
sapper said:
So should I be looking at advancing my ignition, if so how do I do it.
I would leave that for a proper rolling road session TBH. The cooler intake air leads to a denser charge (more oxygen entering the combustion chamber per stroke) so you'll have at least a part of the benefit right away.If you want to set your ignition timing up then you'll need a timing light, preferably one of those with an advance dial so you can find out exactly where the timing is now.
Confirm that the TDC mark on the pulley is correct - many are not - no. 1 sparkplug out and use feelers / dial gauge etc
Mark TDC on pulley with white paint / tippex
Fit timing light in line with no 1 cylinder
Loosen the dizzy clamp bolt - not enough so the dizzy moves freely just so you can move it by hand without it being too stiff
Remove vacuum advance line from dizzy
Start engine run until warm - (mabye do this before fitting timing light etc)
Aim light at the white mark and so so you can see the pointer on the block,
Adjust strobe light with dial until the pointer and TDC mark line up
Read off dial for timing in degrees.
Set dial to where you want it to be ( 8-10°BTDC is fairly normal)
Swing dizzy so TDC mark and pointer line up
Refit everything then go and drive and see if you've got any detonation, typically happens at peak torque ( 3000-4000Rpm) under full throttle.
If you can hear it over everything else come back a few degrees
To do this properly you need a detonation detection system or det cans as they are known
http://autospeed.com/cms/article.html?&A=1353
Easy eh?
Matt
Confirm that the TDC mark on the pulley is correct - many are not - no. 1 sparkplug out and use feelers / dial gauge etc
Mark TDC on pulley with white paint / tippex
Fit timing light in line with no 1 cylinder
Loosen the dizzy clamp bolt - not enough so the dizzy moves freely just so you can move it by hand without it being too stiff
Remove vacuum advance line from dizzy
Start engine run until warm - (mabye do this before fitting timing light etc)
Aim light at the white mark and so so you can see the pointer on the block,
Adjust strobe light with dial until the pointer and TDC mark line up
Read off dial for timing in degrees.
Set dial to where you want it to be ( 8-10°BTDC is fairly normal)
Swing dizzy so TDC mark and pointer line up
Refit everything then go and drive and see if you've got any detonation, typically happens at peak torque ( 3000-4000Rpm) under full throttle.
If you can hear it over everything else come back a few degrees
To do this properly you need a detonation detection system or det cans as they are known
http://autospeed.com/cms/article.html?&A=1353
Easy eh?
Matt
I did something very simular using a small amp from some trashed PC speakers. The output of the knock sensor fed directly into both the left and right channel, and the speakers replaced with a pair of over ear headphones. Although the output of the knock sensor is a lower output than from a PC sound card, the overall signal was large enough to drive the headphones. The Knock sensors are nothing effectively more than piezo microphones, although they may be mechanically tuned to resonate at knock frequencies.
Mark
Mark
crispian22 said:
just fitted a thermal plenum spacer plate from tvr power,also whilst it was off,polished up all the inside's of the trumpets(was thinking of shortening them but need to read more into it)fitted a silicone elbow from plenum to afm,and straight silicone hose from afm to filter,it has made it a completly different car to drive,throttle response is infinatly better,it seems a hell of a lot quicker too throughout the whole rev range.for the cost of a few hours work in the garage and the silcone hose's(£68)it is probably the best thing(and cheapest)i've done to mine so far!!
CrisWhere did you get the silicone hoses from ?
Russ
350Matt said:
If you want to set your ignition timing up then you'll need a timing light, preferably one of those with an advance dial so you can find out exactly where the timing is now.
Confirm that the TDC mark on the pulley is correct - many are not - no. 1 sparkplug out and use feelers / dial gauge etc
Mark TDC on pulley with white paint / tippex
Fit timing light in line with no 1 cylinder
Loosen the dizzy clamp bolt - not enough so the dizzy moves freely just so you can move it by hand without it being too stiff
Remove vacuum advance line from dizzy
Start engine run until warm - (mabye do this before fitting timing light etc)
Aim light at the white mark and so so you can see the pointer on the block,
Adjust strobe light with dial until the pointer and TDC mark line up
Read off dial for timing in degrees.
Set dial to where you want it to be ( 8-10°BTDC is fairly normal)
Swing dizzy so TDC mark and pointer line up
Refit everything then go and drive and see if you've got any detonation, typically happens at peak torque ( 3000-4000Rpm) under full throttle.
If you can hear it over everything else come back a few degrees
To do this properly you need a detonation detection system or det cans as they are known
http://autospeed.com/cms/article.html?&A=1353
Easy eh?
Matt
Way out of my league, but thanks for the advice. Only problem is I now think im missing out on something.Confirm that the TDC mark on the pulley is correct - many are not - no. 1 sparkplug out and use feelers / dial gauge etc
Mark TDC on pulley with white paint / tippex
Fit timing light in line with no 1 cylinder
Loosen the dizzy clamp bolt - not enough so the dizzy moves freely just so you can move it by hand without it being too stiff
Remove vacuum advance line from dizzy
Start engine run until warm - (mabye do this before fitting timing light etc)
Aim light at the white mark and so so you can see the pointer on the block,
Adjust strobe light with dial until the pointer and TDC mark line up
Read off dial for timing in degrees.
Set dial to where you want it to be ( 8-10°BTDC is fairly normal)
Swing dizzy so TDC mark and pointer line up
Refit everything then go and drive and see if you've got any detonation, typically happens at peak torque ( 3000-4000Rpm) under full throttle.
If you can hear it over everything else come back a few degrees
To do this properly you need a detonation detection system or det cans as they are known
http://autospeed.com/cms/article.html?&A=1353
Easy eh?
Matt
sapper said:
Ive been down this route and in the end went for an ACT induction kit, Super flare trumpets, (I tried shortening the originals but made a pigs ear of it. I made an insulator plate from Tufnol carp grade, cost £7 for 2 sheets and onlt used 1. took about 2 hours to make and fit it with nothing more than a drill and a jig saw, More than happy with the results, plenty of pull right through the rev range and the insulator keeps the plenum cool enough to lean on without burning your hand. I already had the plenum off for powder coating otherwise I might never have got round to doing it but im glad i did.
What thickness Tufnol did you use?Groomvroom said:
sapper said:
Ive been down this route and in the end went for an ACT induction kit, Super flare trumpets, (I tried shortening the originals but made a pigs ear of it. I made an insulator plate from Tufnol carp grade, cost £7 for 2 sheets and onlt used 1. took about 2 hours to make and fit it with nothing more than a drill and a jig saw, More than happy with the results, plenty of pull right through the rev range and the insulator keeps the plenum cool enough to lean on without burning your hand. I already had the plenum off for powder coating otherwise I might never have got round to doing it but im glad i did.
What thickness Tufnol did you use?Gassing Station | Chimaera | Top of Page | What's New | My Stuff