Vt vcm otrcai question

[ebbett21]

I had on my carbon fibre OTRCAI replaced today with a VCM aluminium OTRCAI. Now both OTRCAIs look very similar but the VCM fits more snug. After the 2 1/2hr trip home theres definetly an improvement on throttle response rite thru rev range. Im impressed
Question is: Is it normal for the OTRCAI to be hot? I mean after 2 1/2 hour trip the OTR was very very hot is that normal? Whys it hot? Extractor heat ect.

[Delft Maloo]

Its sitting on top of your radiator, which is hotter.

[macca_779]

Metal is a hell of a lot better heat conductor than plastic or fibreglass. Its quite normal for them to get very hot... It's the sole reason why I never recommend them.

[dyno junkie]

Which is the reason I changed from a Ziggy to a RamJet.

[ebbett21]

Metal is a hell of a lot better heat conductor than plastic or fibreglass. Its quite normal for them to get very hot... It's the sole reason why I never recommend them.

if they get so hot, why do VCM sell them over fibreglass? Im interested to know the answer. I can live with a hot OTR as i dont plan on frying eggs or sticking my tongue on it.

I had both fibreglass and now this aluminium one, both setups are near identical in design, the fibreglass one a tad bigger, however both OTRs are running the same size K@N Filter.

The metal one has better throttle response down low and up top, seems crisper. Does VCM do back to back testing with these pre VE air intakes with fibreglass, plastic and metal, if so why did they go with aluminium if they get hot ?

[ebbett21]

old one
http://i1018.photobucket.com/albums/af307/ebbett21/001.jpg

new one=just need a shroud
http://i1018.photobucket.com/albums/af307/ebbett21/002.jpg

To confirm put the old one on and went for a drive and not as responsive , and louder just some info

[macca_779]

The newer style one may offer improved flow design. But I suspect your feeling a placebo effect as the difference between two OTRCAI's shouldn't be noticeable by the seat of the pants unless there is a considerable restriction in place on the poorer performing one. Composition material will have an unmeasurable effect on flow characteristics with all else being equal. The heat soaking of the charge on the other hand will crop up with extended use. If you didn't use the same filter in both that too could explain something. As far as VCM using aluminium over plastic or fibreglass. Its an older design. All the new OTRCAI's are Plastic or Fiberglass, even VCM's.

[ebbett21]

The newer style one may offer improved flow design. But I suspect your feeling a placebo effect as the difference between two OTRCAI's shouldn't be noticeable by the seat of the pants unless there is a considerable restriction in place on the poorer performing one. Composition material will have an unmeasurable effect on flow characteristics with all else being equal. The heat soaking of the charge on the other hand will crop up with extended use. If you didn't use the same filter in both that too could explain something. As far as VCM using aluminium over plastic or fibreglass. Its an older design. All the new OTRCAI's are Plastic or Fiberglass, even VCM's.

I suspect the VCM VT-VZ has been around for a while but its good fits snug. I have felt more responsiveness down low and up top with the aluminium one-interesting enough the engine is quieter:1peek: The old intake had a relaively new filter too. My thinking of why the new one is slightly more responsive is the air is rammed in more to the engine because the intake in slighly smaller. Dunno but seems worthy of the money spent
It would be nice if there was a intake for VT-VZ with a much big filter as really i feel on bigger capacity engines the current is abit small.

[Tyre biter]

This thread had a lot of chat about style and type of OTRCAI including heating if air and placement of IAT sensor.

http://www.ls1.com.au/forum/showthread.php?t=131251

For what it is worth, I run the metal Ziggy unit whilst I've seen significant heat soak of the IAT sensor, it hasn't effected the bottom line (333rwkw) but it did effect hot starts (until the IAT was relocated away from the OTRCAI).

I submitted to the 'forum experts' that despite the heat of the metal OTRCAI, the air entering the same couldn't reasonably be expected to heat to the temps measured by the IAT; not anywhere even close to the same I suggested. My questions were never properly answered by the two more significant protagonists of the thread, and this debate/questions went on and on as to the right place for the IAT regardless of the clearly apparent heat soak the sensor endures inside an OTRCAI, especially a metal one.

Yes, I do think Macca@NJCCorp is on the money about the trend nowadays to move to plastic OTRCAI however as merely a layman on the subject, I do wonder if the driver for this medium is more to do with the malleability of plastic, ease of manufacture, the OEM appearance, and cost per unit as opposed to any significant performance gain.

I wouldn't sweat it - VCM has previously said there are nil plans to make a plastic unit for pre-VE and clearly if there were sale-able performance reasons to go the plastic route then a case would have been made - VCM's choice not to suggests the case to go plastic is not compelling and the metal unit serves the purpose just fine.

Cheers, TB

[ebbett21]

This thread had a lot of chat about style and type of OTRCAI including heating if air and placement of IAT sensor.

http://www.ls1.com.au/forum/showthread.php?t=131251

For what it is worth, I run the metal Ziggy unit whilst I've seen significant heat soak of the IAT sensor, it hasn't effected the bottom line (333rwkw) but it did effect hot starts (until the IAT was relocated away from the OTRCAI).

I submitted to the 'forum experts' that despite the heat of the metal OTRCAI, the air entering the same couldn't reasonably be expected to heat to the temps measured by the IAT; not anywhere even close to the same I suggested. My questions were never properly answered by the two more significant protagonists of the thread, and this debate/questions went on and on as to the right place for the IAT regardless of the clearly apparent heat soak the sensor endures inside an OTRCAI, especially a metal one.

Yes, I do think Macca@NJCCorp is on the money about the trend nowadays to move to plastic OTRCAI however as merely a layman on the subject, I do wonder if the driver for this medium is more to do with the malleability of plastic, ease of manufacture, the OEM appearance, and cost per unit as opposed to any significant performance gain.

I wouldn't sweat it - VCM has previously said there are nil plans to make a plastic unit for pre-VE and clearly if there were sale-able performance reasons to go the plastic route then a case would have been made - VCM's choice not to suggests the case to go plastic is not compelling and the metal unit serves the purpose just fine.

Cheers, TB

Thanks but what is the IAT mean? I do know the car idles abit more radical shake and roll with the VCM
Theres no doubt the VCM setup is not as cheap looking and alot effort gone into making it.
But like you say VCM sell a quality product, im thinking fibre carbon is cheaper to make

[Tyre biter]

IAT = Inlet Air Temperature (sensor).

Not sure if CF is cheaper - but I'd expect (real) CF is very expensive.

As for plastic OTRCAI like the VCM VE unit - very expensive tooling costs but the on-going manufacture is said to be pretty inexpensive as opposed to fabricating something out of sheet metal ad much more durable than fiberglass units.

And yes, at VCM there does seem to be a significant amount of effort toward getting something right (both performance wise and aesthetically) in their corporate culture.

Enjoy your mods and cheers, TB

[ebbett21]

This thread had a lot of chat about style and type of OTRCAI including heating if air and placement of IAT sensor.

http://www.ls1.com.au/forum/showthread.php?t=131251

For what it is worth, I run the metal Ziggy unit whilst I've seen significant heat soak of the IAT sensor, it hasn't effected the bottom line (333rwkw) but it did effect hot starts (until the IAT was relocated away from the OTRCAI).

I submitted to the 'forum experts' that despite the heat of the metal OTRCAI, the air entering the same couldn't reasonably be expected to heat to the temps measured by the IAT; not anywhere even close to the same I suggested. My questions were never properly answered by the two more significant protagonists of the thread, and this debate/questions went on and on as to the right place for the IAT regardless of the clearly apparent heat soak the sensor endures inside an OTRCAI, especially a metal one.

Yes, I do think Macca@NJCCorp is on the money about the trend nowadays to move to plastic OTRCAI however as merely a layman on the subject, I do wonder if the driver for this medium is more to do with the malleability of plastic, ease of manufacture, the OEM appearance, and cost per unit as opposed to any significant performance gain.

I wouldn't sweat it - VCM has previously said there are nil plans to make a plastic unit for pre-VE and clearly if there were sale-able performance reasons to go the plastic route then a case would have been made - VCM's choice not to suggests the case to go plastic is not compelling and the metal unit serves the purpose just fine.

Cheers, TB

TB,
Now without a doubt the VCM gets hotter as opposed to the old one. The IAT sensor is located exactly in the same position as old OTR.
Will my PCM need retuning to compensate for the hotter OTR or will it compensate? My understanding is IAT reads air entering the OTR thru into the engine whilst its moving. If the IAT is in same postion as old it will be fine?
At idle the air temp circulating inside the OTR will be hotter compared to the old one but will this cause and undue effects on ECU and on the engine if pcm isnt tuned for this OTR.?
Thanks

[CHEECH86]

when my car was fitted with the alloy vcm, my mechanic cut a outline of thr OTR out of coreflow* plastic (stuff they use on signs) and layed it between the OTR and the radiator. so for example if i drove for 5 hours straight in 35dergee heat it was still cool enough to stop and lift the bonnet and put your hand on it without burning your hand. only start to heat up when the car is sitting in one position for 5mins or so.

hope this helps

[ebbett21]

when my car was fitted with the alloy vcm, my mechanic cut a outline of thr OTR out of coreflow* plastic (stuff they use on signs) and layed it between the OTR and the radiator. so for example if i drove for 5 hours straight in 35dergee heat it was still cool enough to stop and lift the bonnet and put your hand on it without burning your hand. only start to heat up when the car is sitting in one position for 5mins or so.

hope this helps

Thats a big help mate, the alloy vm intake has a layer of some absorbant under the OTR but will do what you did put a layer strip between otr and radiator as it gets hot...bloody hot. Whats the name of this plastic ? Thanks

[CHEECH86]

Thats a big help mate, the alloy vm intake has a layer of some absorbant under the OTR but will do what you did put a layer strip between otr and radiator as it gets hot...bloody hot. Whats the name of this plastic ? Thanks


No idea what the name is of the plastic but its called "corflute" (google image this name) its white with the the little squares going through it. its hard to explain. they make signs our of the stuff. but yeah it doesn't even warp sitting on a radiator.

[Tyre biter]

TB,
Now without a doubt the VCM gets hotter as opposed to the old one. The IAT sensor is located exactly in the same position as old OTR.
Will my PCM need retuning to compensate for the hotter OTR or will it compensate? My understanding is IAT reads air entering the OTR thru into the engine whilst its moving. If the IAT is in same postion as old it will be fine?
At idle the air temp circulating inside the OTR will be hotter compared to the old one but will this cause and undue effects on ECU and on the engine if pcm isnt tuned for this OTR.?
Thanks

Ebbett, I don't have the technical know-how to answer much of this sorry. My experience being the IAT suffered heat soak with my metal OTRCAI because of the radiant heat of the metal housing. Again, I merely reckon the air inside the OTRCAI cannot in all reasonable expectation be heated to anywhere near the numbers measured by the IAT.

Nevertheless you are right, the temp of the OTRCAI and resultant heat soak of the IAT rises when idling merely because the air isn't moving across it at speed - much like a fan cools you on a hot day - the air temp is statically the same but the movement of the air causes a drop in pressure and thereby a drop in temp - I think this is Carnot's theory or somesuch.

Regardless, heating of the IAT and/or air temp in general causes timing to be adjusted to make the engine run richer and this is a safe outcome as opposed to causing the engine to run lean. That is about the extent of my knowledge and leaves only my opinion; moving the IAT out of a heat soaked environment to measure a temp more in line with actual air temps entering the engine can only be a good thing. This is exactly what I enquired about in the previous thread I mentioned and none of the more schooled folks chose to address this observation - IMHO this is because my observation and similar observations of others did not support the positions taken by purportedly more learnered folk, and unfortunately their inability/unwillingness to properly respond was to the same frustrated any meaningful learning by a number of minions including myself.

Again, have a look at the old thread and make your own mind up as best that you can. My two cents being - if your IAT is measuring air temps well above ambient then it is suffering heat soak (the sensor as opposed to the air passing it) and thereby it needs to be moved. Even VCM told me this.

Good luck with it all and cheers, TB

[ebbett21]

Ebbett, I don't have the technical know-how to answer much of this sorry. My experience being the IAT suffered heat soak with my metal OTRCAI because of the radiant heat of the metal housing. Again, I merely reckon the air inside the OTRCAI cannot in all reasonable expectation be heated to anywhere near the numbers measured by the IAT.

Nevertheless you are right, the temp of the OTRCAI and resultant heat soak of the IAT rises when idling merely because the air isn't moving across it at speed - much like a fan cools you on a hot day - the air temp is statically the same but the movement of the air causes a drop in pressure and thereby a drop in temp - I think this is Carnot's theory or somesuch.

Regardless, heating of the IAT and/or air temp in general causes timing to be adjusted to make the engine run richer and this is a safe outcome as opposed to causing the engine to run lean. That is about the extent of my knowledge and leaves only my opinion; moving the IAT out of a heat soaked environment to measure a temp more in line with actual air temps entering the engine can only be a good thing. This is exactly what I enquired about in the previous thread I mentioned and none of the more schooled folks chose to address this observation - IMHO this is because my observation and similar observations of others did not support the positions taken by purportedly more learnered folk, and unfortunately their inability/unwillingness to properly respond was to the same frustrated any meaningful learning by a number of minions including myself.

Again, have a look at the old thread and make your own mind up as best that you can. My two cents being - if your IAT is measuring air temps well above ambient then it is suffering heat soak (the sensor as opposed to the air passing it) and thereby it needs to be moved. Even VCM told me this.

Good luck with it all and cheers, TB

Im thinking the OTR gets so hot is because its ontop of the radiator, so if that can be rectified then problem solved.. I do think the heat sock is minimal unless your driving for hours on end. The air entering the OTR after accelerating from idle will cool it, however problem being the OTR gets hotter and hotter from the radiator as the time goes by. .the OTR inside must be like a oven. Im starting to wonder the benefit is from a metal OTR
Thanks,

[ATOMIC MALOO R8]

Ebbett, I don't have the technical know-how to answer much of this sorry. My experience being the IAT suffered heat soak with my metal OTRCAI because of the radiant heat of the metal housing. Again, I merely reckon the air inside the OTRCAI cannot in all reasonable expectation be heated to anywhere near the numbers measured by the IAT.

Nevertheless you are right, the temp of the OTRCAI and resultant heat soak of the IAT rises when idling merely because the air isn't moving across it at speed - much like a fan cools you on a hot day - the air temp is statically the same but the movement of the air causes a drop in pressure and thereby a drop in temp - I think this is Carnot's theory or somesuch.

Regardless, heating of the IAT and/or air temp in general causes timing to be adjusted to make the engine run richer and this is a safe outcome as opposed to causing the engine to run lean. That is about the extent of my knowledge and leaves only my opinion; moving the IAT out of a heat soaked environment to measure a temp more in line with actual air temps entering the engine can only be a good thing. This is exactly what I enquired about in the previous thread I mentioned and none of the more schooled folks chose to address this observation - IMHO this is because my observation and similar observations of others did not support the positions taken by purportedly more learnered folk, and unfortunately their inability/unwillingness to properly respond was to the same frustrated any meaningful learning by a number of minions including myself.

Again, have a look at the old thread and make your own mind up as best that you can. My two cents being - if your IAT is measuring air temps well above ambient then it is suffering heat soak (the sensor as opposed to the air passing it) and thereby it needs to be moved. Even VCM told me this.

Good luck with it all and cheers, TB

do a search on the best IAT sensor position theres a lot of pages on it :rofl: