TB to IM port matching mod. who has tried this?

[keeders08]

LET ME KNOW your results.


- This is the TB port matched to the TB
- Also the TB has the half-shaft mod.

[Diablo0]

Well... I have a ported and polished magnum intake mani with a 3" inlet welded on to make it match up with my 60mm TB. I wouldn't say it was a huge gain but as we all know, every little bit counts and is more or less a supporting mod.

[keeders08]

Well... I have a ported and polished magnum intake mani with a 3" inlet welded on to make it match up with my 60mm TB. I wouldn't say it was a huge gain but as we all know, every little bit counts and is more or less a supporting mod.

Truue that sir.

Diablo, how hard would it be to swap to magnum head/IM/exhaust man./ECU?
-And obviously you know I want opinions that are helpful unlike alot of these ppl on here that just want to dog your ideas...

Also.. i want ur honest educated opinion on exhaust backpressure.. w/e 2 cents ud like to give out.. i dont mean advice, i just mean YOUR take on the subject,

[Diablo0]

It's something you could do in a weekend or even a day if you knew what you were doing but it's going to quite a bit more difficult than installing a CAI. Keep in mind that you dont' have the Magnum engine harness so you wouldn't have the wiring for the butterflies in the intake manifold so you'd have to do some wiring for that as well to take full advantage of the intake mani.

Exhaust backpressure... I'd say it's not so much about back pressure but keeping exhaust gas velocity. You dont' want an exhaust pipe thats too small to be restrictive but at the same time you don't want one that's too big to cut down on the air velocity flowing through it. By that I mean okay, take one of those little coffee stir straws thats really small and imagine it being 3 feet long. Try to blow through it... probably going to be hard to do huh but you still feel air coming out the end? Compared that to small piping... Now, take a 2" diamater PVC pipe thats 3' long and try to blow through it. A lot easier to blow through it but at the end of the pipe you don't feel as much air coming out. It's kind of like that on a much larger scale. If the piping is too large as the exhaust gas comes out of the engine it starts to cool down. As it cools it gets denser and harder to move and for lack of a better word, sort of puddles up in the exhaust pipe making it hard for the engine to push that denser air out. The air then slows down and in it's own way becomes a restriction.

Hopefully I explained that pretty well but if not I'm sure someone will correct me lol

[occasional demons]

LET ME KNOW your results.


- This is the TB port matched to the TB
- Also the TB has the half-shaft mod.

Your intake/TB isn't true to the term, as it can move ever so slightly with that coupler. if it was bolted with a flange on both TB and IM and the flanges/gasket were the same shape/I.D. and aligned, then they would be port matched to be true to the definition, but the power gain over what you currently have wouldn't be worth the trouble unless you were going with a larger TB bore. The only possible downside to that setup is you're losing a small amount of plenum volume. Is it enough to affect anything?????? only a dyno will tell.

[keeders08]

It's something you could do in a weekend or even a day if you knew what you were doing but it's going to quite a bit more difficult than installing a CAI. Keep in mind that you dont' have the Magnum engine harness so you wouldn't have the wiring for the butterflies in the intake manifold so you'd have to do some wiring for that as well to take full advantage of the intake mani.

Exhaust backpressure... I'd say it's not so much about back pressure but keeping exhaust gas velocity. You dont' want an exhaust pipe thats too small to be restrictive but at the same time you don't want one that's too big to cut down on the air velocity flowing through it. By that I mean okay, take one of those little coffee stir straws thats really small and imagine it being 3 feet long. Try to blow through it... probably going to be hard to do huh but you still feel air coming out the end? Compared that to small piping... Now, take a 2" diamater PVC pipe thats 3' long and try to blow through it. A lot easier to blow through it but at the end of the pipe you don't feel as much air coming out. It's kind of like that on a much larger scale. If the piping is too large as the exhaust gas comes out of the engine it starts to cool down. As it cools it gets denser and harder to move and for lack of a better word, sort of puddles up in the exhaust pipe making it hard for the engine to push that denser air out. The air then slows down and in it's own way becomes a restriction.

Hopefully I explained that pretty well but if not I'm sure someone will correct me lol

Well I do understand exhaust um just tryin to get some back up on the issue lol, ppl seem to be tryin to tell others they dont need any backpressure, which is wrong.

my set up is going to be this...

OBX header/downpipe, high flow cat, stainless res, or moroso inline muffler, and a dynomax muffler...

ur opinion on my setup idea is def. welcome

[esteinmaier]

Well I do understand exhaust um just tryin to get some back up on the issue lol, ppl seem to be tryin to tell others they dont need any backpressure, which is wrong.

Did you even read what Diablo wrote? He just told you that you don't need back pressure. He gave you a thorough explanation.

[keeders08]

Well I do understand exhaust um just tryin to get some back up on the issue lol, ppl seem to be tryin to tell others they dont need any backpressure, which is wrong.

Did you even read what Diablo wrote? He just told you that you don't need back pressure. He gave you a thorough explanation.

Yea if u have small enough piping.....

[esteinmaier]

You're just not getting it. I don't know how any of us can make it more clear.

[TN.Frank]

I've been thinking about getting a coupler and hooking the TB to the Intake like that for some time now, just need to get around to it. Then I can get a tube to run form the TB to the intake box and re-mount my air cleaner to it. That should give me a sort of "velociety scoop" kind of deal with the tubing going into the TB. Still, I might just hook the air filter to the TB and let it pull air from the engine bay, I know it'd not be the best air but it'd be simple and I could get rid of my stock air box then and make more room under the hood. Still kickin' it around though. Would the intake to TB coupler be 2"? That's what I seemed to understand from some other posts.

[keeders08]

I've been thinking about getting a coupler and hooking the TB to the Intake like that for some time now, just need to get around to it. Then I can get a tube to run form the TB to the intake box and re-mount my air cleaner to it. That should give me a sort of "velociety scoop" kind of deal with the tubing going into the TB. Still, I might just hook the air filter to the TB and let it pull air from the engine bay, I know it'd not be the best air but it'd be simple and I could get rid of my stock air box then and make more room under the hood. Still kickin' it around though. Would the intake to TB coupler be 2"? That's what I seemed to understand from some other posts.

Distance Conversion site... all u need is ur TB's size. 52 or 49mm

http://www.convert-me.com/en/convert/length

ATX TB is 52mm MTX is 49mm.... I beleive 52mm is 2 inches tho

[Diablo0]

It's something you could do in a weekend or even a day if you knew what you were doing but it's going to quite a bit more difficult than installing a CAI. Keep in mind that you dont' have the Magnum engine harness so you wouldn't have the wiring for the butterflies in the intake manifold so you'd have to do some wiring for that as well to take full advantage of the intake mani.

Exhaust backpressure... I'd say it's not so much about back pressure but keeping exhaust gas velocity. You dont' want an exhaust pipe thats too small to be restrictive but at the same time you don't want one that's too big to cut down on the air velocity flowing through it. By that I mean okay, take one of those little coffee stir straws thats really small and imagine it being 3 feet long. Try to blow through it... probably going to be hard to do huh but you still feel air coming out the end? Compared that to small piping... Now, take a 2" diamater PVC pipe thats 3' long and try to blow through it. A lot easier to blow through it but at the end of the pipe you don't feel as much air coming out. It's kind of like that on a much larger scale. If the piping is too large as the exhaust gas comes out of the engine it starts to cool down. As it cools it gets denser and harder to move and for lack of a better word, sort of puddles up in the exhaust pipe making it hard for the engine to push that denser air out. The air then slows down and in it's own way becomes a restriction.

Hopefully I explained that pretty well but if not I'm sure someone will correct me lol

Well I do understand exhaust um just tryin to get some back up on the issue lol, ppl seem to be tryin to tell others they dont need any backpressure, which is wrong.

my set up is going to be this...

OBX header/downpipe, high flow cat, stainless res, or moroso inline muffler, and a dynomax muffler...

ur opinion on my setup idea is def. welcome

It's not really that you need back pressure, it's that you need to find the correct balance of pipe size. Too small and you have a restriction just like taking and trying to blow through through that coffee stir straw. Too large though and the air itself becomes it's own restriction since the new exhaust gas being forced out of the engine and into the exhaust manifold must push all the air in front of it out of the way. The longer the gas sits inside the exhaust piping the more it cools. More it cools, the denser it gets which in turn becomes more air the new air entering the system much push through the piping. This is why you want to try to keep the heat in your exhaust system so the air stays less dense and moves easier. It's not really about back pressure, like I said... it's about the velocity of air exiting the chamber and continuing to travel down the pipe.

[keeders08]

It's something you could do in a weekend or even a day if you knew what you were doing but it's going to quite a bit more difficult than installing a CAI. Keep in mind that you dont' have the Magnum engine harness so you wouldn't have the wiring for the butterflies in the intake manifold so you'd have to do some wiring for that as well to take full advantage of the intake mani.

Exhaust backpressure... I'd say it's not so much about back pressure but keeping exhaust gas velocity. You dont' want an exhaust pipe thats too small to be restrictive but at the same time you don't want one that's too big to cut down on the air velocity flowing through it. By that I mean okay, take one of those little coffee stir straws thats really small and imagine it being 3 feet long. Try to blow through it... probably going to be hard to do huh but you still feel air coming out the end? Compared that to small piping... Now, take a 2" diamater PVC pipe thats 3' long and try to blow through it. A lot easier to blow through it but at the end of the pipe you don't feel as much air coming out. It's kind of like that on a much larger scale. If the piping is too large as the exhaust gas comes out of the engine it starts to cool down. As it cools it gets denser and harder to move and for lack of a better word, sort of puddles up in the exhaust pipe making it hard for the engine to push that denser air out. The air then slows down and in it's own way becomes a restriction.

Hopefully I explained that pretty well but if not I'm sure someone will correct me lol

Well I do understand exhaust um just tryin to get some back up on the issue lol, ppl seem to be tryin to tell others they dont need any backpressure, which is wrong.

my set up is going to be this...

OBX header/downpipe, high flow cat, stainless res, or moroso inline muffler, and a dynomax muffler...

ur opinion on my setup idea is def. welcome

It's not really that you need back pressure, it's that you need to find the correct balance of pipe size. Too small and you have a restriction just like taking and trying to blow through through that coffee stir straw. Too large though and the air itself becomes it's own restriction since the new exhaust gas being forced out of the engine and into the exhaust manifold must push all the air in front of it out of the way. The longer the gas sits inside the exhaust piping the more it cools. More it cools, the denser it gets which in turn becomes more air the new air entering the system much push through the piping. This is why you want to try to keep the heat in your exhaust system so the air stays less dense and moves easier. It's not really about back pressure, like I said... it's about the velocity of air exiting the chamber and continuing to travel down the pipe.

well see thats pretty much what i meant about backpressure, not necessarily making its velocity ne less, just getting to to the point that its not just stealing all of your torque...

[esteinmaier]

Back pressure does not make torque. It steals it.

[keeders08]

Back pressure does not make torque. It steals it.

i understand what ur saying, but its obvious powerloss when i took my cat off, plain and flippin simple man.... im done discussing this.

[BlackRoseRacing]

No offense, but if you did not understand what Diablo just explained, then you should not be behind a wrench. N/A Vs FI are 2 totally different elements, if your N/A everything Diablo just explained is TRUE!
Take what he stated and think about it.....



PS - Since this topic is going to turn rough, maybe...I'll leave it here for now

[Canada]

Distance Conversion site... all u need is ur TB's size. 52 or 49mm

http://www.convert-me.com/en/convert/length

ATX TB is 52mm MTX is 49mm.... I beleive 52mm is 2 inches tho

All 2GN Throttle bodies are 52mm, there is no difference between ATX and MTX, it's not a 1GN.

[keeders08]

Distance Conversion site... all u need is ur TB's size. 52 or 49mm

http://www.convert-me.com/en/convert/length

ATX TB is 52mm MTX is 49mm.... I beleive 52mm is 2 inches tho

All 2GN Throttle bodies are 52mm, there is no difference between ATX and MTX, it's not a 1GN.

Well i stand corrected sir.

No offense, but if you did not understand what Diablo just explained, then you should not be behind a wrench. N/A Vs FI are 2 totally different elements, if your N/A everything Diablo just explained is TRUE!
Take what he stated and think about it.....



PS - Since this topic is going to turn rough, maybe...I'll leave it here for now

I have no feelings to offend , i never claimed to be an expert on exhaust. lol as for what Diablo explained, i do understand what hes saying, but as far as telling me that removing the cat produced more power.... im just not even gonna begin.. better the whole thing be left alone.

[pandevida85]

remember dude you have an auto.. everything you do translates through that tranny and power gains and loss feel different. i've seen people with built engines on their atx and go no where off the line fast. The auto tranny reacts different than stick and so does power delivery to the wheels. Just thought I'd point that out.

[keeders08]

remember dude you have an auto.. everything you do translates through that tranny and power gains and loss feel different. i've seen people with built engines on their atx and go no where off the line fast. The auto tranny reacts different than stick and so does power delivery to the wheels. Just thought I'd point that out.

im still wondering how all these ppl got involved in this topic lol. I expected Diablo to reply cuz he always does.

But yea i guess the whole ATX thing makes sense, but wait til i swap to MTX, we'll see how things go lol

[SGT BRAD]

[quote="keeders08
I have no feelings to offend , i never claimed to be an expert on exhaust. lol as for what Diablo explained, i do understand what hes saying, but as far as telling me that removing the cat produced more power.... im just not even gonna begin.. better the whole thing be left alone. [/quote]

maybe this will help. it's not the backpressure that causes an increase in tq. it's having an exhaust system volume that matches the exhaust gas volume causing what's called, "scavenging." it's why 2 stroke motorcycles have different sized expansion chambers. change the size/shape of the chamber and you change, 1. the volume and 2. the velocity. btw part of the reason cats seem to help has more to do with the amount of heat that they hold in the front end of the exhaust system than with any backpressure that they create.

[NickKo]

maybe this will help. it's not the backpressure that causes an increase in tq. it's having an exhaust system volume that matches the exhaust gas volume causing what's called, "scavenging." it's why 2 stroke motorcycles have different sized expansion chambers. change the size/shape of the chamber and you change, 1. the volume and 2. the velocity. btw part of the reason cats seem to help has more to do with the amount of heat that they hold in the front end of the exhaust system than with any backpressure that they create.

I've never thought about the heat being generated by the converter helping to keep up velocity.
Good explanation, it makes sense, to me anyways.

Thanks for the tech info, Sgt.Brad.

-Nick

[occasional demons]

Exhaust wrap will help keep the heat in to some extent also. The ideal pipe would be one that can change diameter based on temperature and engine rpm, kinda like a living exhaust pipe. And the same could also apply to the intake, at least the rpm part, but it hasn't been invented yet. Meh, it would be a bit creepy tho.

[OB]

Diablo0 said it best in his first post. Backpressure isnt something needed to make power or torque, this is a myth. Velocity, temperature, and turbulence are the important factors regarding exhaust flow. There are formulas to calculate exhaust pipe diameter and header runner length based on engine displacement and CFM of air flowing through that engine. Exhaust calculations can get very complicated very fast, so unless you're building a race motor and need every last bit of power, the best thing to do is stick with the factory engineering and leave it alone. Changing diameter is a common mistake that tuners make when upgrading exhaust. Unless the engine is flowing a LOT more air, there is no need for this. The factory piping is more than enough at 2.25". The only way to get more power by just bolting up exhaust parts would be to get piping with cleaner/less bends, a mild header, and a higher flowing muffler. The cylinder head and intake system are also important to address for maximum gains. An upgrade to the magnum head would be more than enough for any street car.

As far as i'm concerned, the stock exhaust is a very well engineered system. The muffler is restrictive, as is the exhaust manifold, but neither enough so that there is much power to be found. Taking those out of the loop are a good idea. The piping is decent, but the money spent to change to mandrel bent piping probably isnt worth the 0-2HP/TQ gain. Removing the cat is another way to get a small amount of power. As mentioned in another post, using header wrap or ceramic coating exhaust components is a great way to keep heat in and promote good flow. This is also good for a small amount of power in many cases.

The reason the powerband shifts to the top end when removing restrictions from the exhaust system is simple. The exhaust gas velocity is much lower at lower engine speeds. The engine isn't sucking in as much air, therefore there isnt much left over to exhaust. Less air means less heat after combustion, resulting in lower EGT's. At higher RPM, exhaust flow begins to pick up. Pipe size and design come into play a lot more when the velocity starts to reach these higher levels. This is why gains are felt in the upper portion of the powerband. A higher flowing system gets rid of exhaust gases faster, which in turn results in getting rid of heat faster, often showing up on the dyno graphs as a loss of low end torque. Removing the cat does indeed change the thermal characteristics of the exhaust system. However, by the time the exhaust gets towards that portion of the system, retaining heat is very difficult anyway. Keeping heat up to the catalyst is the ideal way to promote proper EGT's and keep flow up. The rest of the piping after this portion is simply a path for the gas to enter the atmosphere, and has little to do with performance, except maybe to hurt it a bit. This is why true racecars use a long tube header design, calculated to end as soon as thermally possible, making the most power and flowing with as much heat as possible before exiting.

[keeders08]

Well see i understand all the things you all are saying. Its just my way of explaining it is "back pressure" but in reality its not actually that lol... i just had no other way to explain what i was saying. And yea i know all bout 2 stroke exhausts and everything, i used to rebuild my friends blaster evry damn 3 wks to a month cuz he raced it. we experimented back in the day with diff size, different shaped exhausts, even tho his dad straight TOLD us what each would do. I guess a moto mechanic WOULD know, but hey its better to learn the hard way, which is what i do with cars becuz i have no one to teach me. Trail n error is the best way.


And I never thought about the heat thing either...i wonder if that'd work on a quad? lmao The heat wrap part, ne way...

I'm glad i started this Subject, it'll end up helpin a lot of newbies, not that im an expert, but its all good information.


Bob's ur uncle

[kc2005ptgt]

I am going to say that you are WRONG when you say that removing the cat will NOT produce power... I have proof of it, from a dyno. With the addition of a LTH, mygain was from 135.5 to 143.5hp and no gain in trq.

[keeders08]

I am going to say that you are WRONG when you say that removing the cat will NOT produce power... I have proof of it, from a dyno. With the addition of a LTH, mygain was from 135.5 to 143.5hp and no gain in trq.

ur shit aint stock then bro, neons wont dyno 135.5 stock.

[Wenuden]

it's an r/t acr... Rated for 150@ the crank.

[keeders08]

it's an r/t acr... Rated for 150@ the crank.

Thats wat i thought u were measuring... crank 135.5 thats more than an SXT and less than R/T ACR... confused me lol

[INVUJerry]

it's an r/t acr... Rated for 150@ the crank.

Thats wat i thought u were measuring... crank 135.5 thats more than an SXT and less than R/T ACR... confused me lol

150 at the crank on an ACR is 135 at the wheels.

I think my 98 would dyno at 125 lol.