josiel

im planning on doing this as mynext mod porting and polishing intake manifold and throttle body. Is there any HP gains also do i need to get a custom butterfly any info will help me thanks

anx1300c

iTrader: (2)

These guys can hook you up. They machine and install a larger butterfly for you. I may send them my TB and then have the intake/runners ported and matched somewhere else. Just make sure you have the intake bored to match the larger TB.

http://maxbore.com/

Comptechtl2367

Nice! I may have to send mine out before i bolt it up to the S/C!

I hate cars

This would be a great addition to a supercharged car since the TB is before the blower. For a turbo car it's a complete waste of money. For NA, you're only going to pick up part throttle hp but full throttle will be the same.

silverbullitt

as any "true" engine expert will tell you, ( no, I am not an expert,) an engine is a thermal air pump, simplified analogy.
and so the efficiency of an engine in theory, is to be able
to suck in ( mix with fuel, burn it,) and to expel the burned
by products out- and in the case of a turbo or supercharger,
it is needed more to work with the increased breathing ability.
naturally aspirated engines need help in breathing, and in
removing any "excessive restrictions" ( some restrictions actually help to produce low end torque in a street driven vehicle. So to dispute the answer that a throttle body wont help at mid and higher rpms is a bunch of poop..
at low rpm, is when it wont help-(as much) 900rpm to 2,3000rpms , mid rpms and higher is when it will help the most- at lower engine speeds, the velocity of the air entering will help build torque- take away velocity, lose torque- same applies to an overly large exhaust system-
as well as the examples of poorly matched intakes( aligning of ports) etc. hope this helps-

I hate cars

Wrong.

If the factory throttlebody poses no restriction to the engine at full throttle then a larger one can't increase airflow or hp. The TL uses a large throttlebody in stock form, more than the engine can use at full throttle. You can increase it to 5" and it won't make a difference in full throttle power. It will only make a difference in part throttle power where the TB is the restriction. The TB HAS to be the restriction at part throttle, it's designed that way, it "throttles" the engine by restricting airflow.

You're wrong too about restrictions such as exhaust increasing torque. This is a myth that won't die.

Intake restrictions can not affect the part throttle powerband or torque, only the full throttle power.Why would you want a throttlebody to help at low rpm/low throttle? It is the restriction, it's sole purpose is to restrict the airflow at low throttle. If it didn't restrict airflow, we would only have full throttle, no idle or part throttle. You want it to restrict airflow at part throttle and become invisible to the engine at full throttle which the stock TL throttle body does.

nutnut

It is not. If it were, there wouldn't be valve overlap for example.

ethenol

Valve overlap............. HAHAHAHAHA......... I have 19 inch exhaust on my TL. With a 90mm TB and Its way fast bro......... Cus of valve overlap.....ppppppppppppppppfffffffffffftttttttttt ttt!!!!!!!!!!!

I hate cars

Do you even know what valve overlap is? Exhaust restrictions decrease torque.

anx1300c

iTrader: (2)

No way man, I stuck a potato in each of my tailpipes and then threw it on a dyno and made 480 ft lbs. This was on a Mustang dyno, no less, so it would be closer to 550 ft lbs on a Dynojet!

Comptechtl2367

Yeah thats what my thought was, i am taking the inlet off the supercharger to have it bored to 70mm with the throttle body.

I hate cars

With the extra airflow especially since it's on the suction side it will help. Plus, reducing restriction before the supercharger will reduce outlet temps. Are you already supercharged or are you going to do this all at the same time. I would be curious of any gains.

nutnut

Yes I do, do you? Exhaust pipe while being a restriction increases torque.

Comptechtl2367

I was going to install everything at once, but now i may consider doing the s/c, dyno, then port and dyno. It would be intresting to see the difference if any. The only issue is there is crap for tuners in Madison so ill have to find a dyno.

I hate cars

Welcome to 2010. Leave the 1960s myths at the door. As it was said, why not stick a potato in the pipe for some good torque gains?

anx1300c

iTrader: (2)

You obviously don't realize that horsepower and torque are unequivocally, mathematically related. And that their relationship is directly proportional. And that what that means is that if one is increased, then so is the other. (And vice-versa)

So what you're effectively saying here is that restricting exhaust flow will increase horsepower and torque.

Awesome.

Sonnick

You didn't know this?? z0mg

I'd assume that with an increase to the size of the TB, that the piping of the CAI should be increased as well. However, I believe that most of the CAI piping is already over 3", which would mean that really nothing needs to be done unless you are running the new TL 3.7L throttle body. And even then doesn't it taper down to 70mm, making this part of my post irrelevant?

I'd think with a bored TB and ported IM/runners, there would be a sufficient gain.

I hate cars

I look at it as you can't hurt anything by going "too big" on the CAI plumbing. The minimum size would be the size of the throttlebody. Remember, the total restriction is the sum of all restrictions, not the largest restriction. If the CAI plumbing is going to be long, it might not be a bad idea to have it slightly larger than the TB. If it's just a couple feet without a ton of curves, the same size as the TB is fine.

3" is more than enough for a 300hp engine. This is why I say going any larger will not produce full throttle gains. If the TB is not a restriction when fully open, going larger can't help. However, since the hole is larger when you partially open the throttle you're flowing more air at the same throttle%. The car will make more power for the amount of throttle you give it but it's the same as opening the stock TB more.

IMO, this would be a better alternative to the Sprint booster. It's a mechanical way of doing the same thing. Remember how the guy said this product will not make the car quicker but it will make it more responsive? This is the exact same thing but you're doing it mechanically.

nutnut

unlike a (proper sized for given volume of exhaust gases) pipe, the potato wont focus the exhaust pulses out of the cylinder and provide no gains

a smaller pipe will increase torque (and hp) at low rpm, and it will also hurt hp at higher rpm, where it becomes too restrictive for the increased volume of the exhaust gases

you can hurt low end torque by too wide intake as well
remember both exhaust and intake are series of pulses and not a steady stream, each pulse has its inertia that helps it to enter the cylinder in case of the intake, and suck out the next charge of exhaust gases in case of exhaust, by creating vacuum behind its tail (and suck in more mixture during valve overlap)

I hate cars

You said restriction gives more low end torque in your previous post, not scavenging which is what you're mentioning here. Most factory setups don't have enough exhaust energy to take advantage of scavenging. Throw a large cam and it might change.

Maybe on a 2-stroke lol.

In reality, a small pipe will take away low end torque and high rpm hp. It's been proven time and time again on the dyno. It can be proven in theory too. Explain how a smaller pipe (restriction) can help low rpm torque.

The bottom line is getting exhaust out of the engine as easily as possible will make the most torque, not restricting it. This is the old way of thinking which should be gone by now.
The throttlebody has no effect on powerband, none whatsoever. I have no idea what you mean by "too wide intake" but let's assume for the sake of argument in this thread that you're talking about the throttlebody since that's what the thread is about.

By your argument, pushing the gas pedal will make you lose low end torque since you're opening the throttlebody and decreasing restriction. Do you see a problem with this logic? Last I checked, the engine makes MORE power the more you open the throttle.

Your recipe for making torque would get you an engine that could barely move the car.

Sonnick

^^ I think what "nut" means is that a smaller pipe close to the engine will make more hp/tq than a larger pipe close to the engine. For example, there's a reason why most of the V8 header primary pipes are 1 7/8IN as opposed to > 2IN. However, after the collector, everything else is a restriction. That's why cutouts usually make the most power because they are open right after the merge collector.

This test was also done by Tony @ Motordyne for the VQ motors. He took 2IN, 2.25IN & 2.5IN piping close to the head and dyno'd after each one. The 2IN had the best of both worlds. The 2.5IN had less torque at lower RPM than the 2IN & 2.25IN pipes. However, at the top I believe they all made similar power.

This is why stepped designs are very useful in NA applications. As long as the exhaust velocity is kept high, power will be made.