Depends on if the shift timing is based on throttle position or manifold vacuum. I'm not sure which it is. One thing for sure, make sure you get the 75mm 600hp TB for the biggest gains.

 

dude, that's 6 hp per $1! I'll take 5 of them since they're cheap.

 

Man those are razor thin...


Nice dogs.. they look like bed / couch hogs.. if you leave they take your spot.

 

NO the dogs have there own bed. IT"S A QUEEN!

 

 

I went to that site and emailed him a couple days ago to try and get the address, but no response. Any other way to contact him?

 

He will take a few days. He emailed me at like 10ish at night. I have his address.

 

Even if the sprint booster actually did something and was priced reasonably, I wouldn't buy one because the name alone is so cheesy.

 

You're exactly right on all accounts. The larger TB improves throttle response because what use to be 15% throttle is now 20% throttle, 50% throttle is 65% throttle, etc. There's no power to be gained because most OEM TBs are way bigger than the motor can fully utilize anyways. If 600-1000whp turbo VQ35s aren't restricted by the OEM 70mm TBs, I highly doubt an NA/FI TL would be restricted by the OEM 65mm TB.

Have you guys confirmed that boring out the TB won't have an adverse effect on the stability/traction control system? Those systems rely heavily on the exact power measurements and throttle inputs. Change the TB size and you might through that whole stability control system out of whack where it might actually work against you since it thinks the throttle is at one setting, when in reality it's at another.

Also, the ECU, MAF, and injectors are tied closely together. Changing the TB size could cause a major issue, especially an idle issue. What might have worked on cable TBs doesn't work real well on drive-by-wire TBs.

 

The TL doesn't have a MAF sensor it utilizes a MAP sensor and boring out the TB may cause an intermittent CEL but typically the ecu recognizes the change after a short period and it goes away or balancing out the intake & exhaust pressure has resolved the issue. I'm unaware of the TL using inputs from the intake as part of the TCS. RacingHart is already running a 70mm bore and no problem whatsoever.

 

Agreed on the sizing and pretty much everything you said. heck, I have a bored out 58-65mm stock TB on my GN at roughly 700 flywheel hp.

The ECM will learn the idle characteristics. It uses timing to to make fine adjustments in the idle and the throttle for the larger ones. I suspect it may have an unsteady idle at first, maybe overcompensate for when the AC compressor kicks in but these are all things it learns over time.

No MAF (unfortunately) on these cars so the larger TB will show a corresponding decrease in manifold vacuum for a given throttle opening. Not much difference in taking your TL from 10,000 feet down to sealevel. In other words it will relearn. Now if you put dual 90mm TBs on there you may have problems.

 

If bigger throttle body had no benefit then why did Acura themselves put a 69mm throttle body on their 3.7L motor, a whole 5mm larger than what goes on their 3.5L motors?

Also I had mine bored out from the 69mm to 72mm, and then opening from 79mm to 82mm... as soon as I turned the car on the idle was perfect with no issues whatsoever. The only noticeable difference was better response and more power... but I did do some other modifications at the same time.
https://acurazine.com/forums/4g-tl-performance-parts-modifications-295/bored-throttle-body-p2r-spacer-p2r-thermal-gaskets-installed-726258/

So many guys over here act like they know lots of information which I don't doubt, they only ever cite experiences outside of these cars. Especially this Dave guy who I'm sure in all respects is here to just help people, he unfortunately produces tons of misinformation. In fact people have been putting bigger bore throttle bodies on these J motors for years with only positive experiences on the dyno and track.

 

Dave is one of the most knowlegable people on here.

The J32 is not special, it follows the laws of physics. A certain size TB will flow a certain amount of air without restriction. It takes a certain amount of air to make a certain amount of hp. It's all about airflow and you can predict how much hp an engine makes within a few percent by knowing just the airflow. It doesn't matter if it's an Acura, a Mustang, a Vette, Ferrari, etc, the same rules apply no matter what.

The reason a larger TB is used on the larger engines is more for throttle response, not for all out hp. 70mm is way overkill for a 300hp car.

I read your thread and did not see a dyno or track run to back up the claim that it makes more hp. All you're going to notice is more power down low (in the pedal travel) because it's the equivilent of opening the throttle more with the stock TB. It's the same as the sprint booster, more throttle opening for a given pedal travel but no extra hp. The thing is, you're now going to hit full hp somewhere around 3/4 throttle and it's not going to get any more power in that last 1/4 of the travel.

I'm not trying to start anything here but airflow vs hp vs TB size is common info. The largest variable is whether you're NA or FI.

 

Right, it's not going to increase your horse power but it will give the the horse power you already have quicker and right from the start. Better throttle response feels faster, the engine breathes better.

 

I Hate Cars, would you see a decrease in mpg? I remember you had a tidbit once that the intake will only induce the specific amount of air required for combustion and no more...it was in regards to a Ram Air induction thread - can't force more air down than it will accept.

Am I butchering that train of thought?

 

Any change in mileage?

 

I would guess your mpg would decrease.. more air more fuel.

 

Isn't the throttle postion sensor one of the TCS/VSA input components? If so, I can see what Dave is saying about the throttle position reads, say, 20%, but since the TB is bigger that may be equal to, say, 25%.

How is the throttle position measured? By the butterfly opening, by the pedal depression, etc,?

 

yeah it is.. was only thinking of MAP sensor.. I guess the effectiveness would decrease but I wouldn't think it would cause any major error.

 

throttle position sensor I think theres 2..... I dont remember...but to get my VAFC2 working i had to tap into the first sensor. its very very accurate and i think its determined from the 2 one from the foot pedal one from the throttle body. i havent looked or analyzed the electrical schematic

 

Should stay the same. A/F is unaffected so once you adjust your driving style to the better response it won't be altered.

 

I don't have the time to go searching threads, but there are plenty with 2G CL who bored throttle body and show only positive experiences. Why would Acura put 69mm if it is overkill? You don't think they put their motors on dyno stands to test out what works the best? The thing people love to rant about is basic laws of physics... that's great and I'm all for it. But there are many variables that are different amongst cars... intake runner length, compression, cam timing, exhaust systems for efficient scavenging (by putting more air into the motor you need to remove it faster as well). My biggest problem with Dave is that he just touts the very general automotive basics, discrediting many things, when there is plenty of proof on these forums since 2000 of people manipulating the J motor and showing what works and what doesn't.

The fact is, what works on one car may not work on another. Even if a motor is a motor, and 2 motors may be similar in design. Certain things that work on the Nissan motors show no gains on a Honda J motor. And vica versa. You don't know until someone tries it. The same rules do not apply.

As I said, go searching forums, and you will find people running quality track times with larger throttle bodies, both N/A and FI. I said I felt power, but also did other modifications at the same time as the throttle body. The way a motor loses power is typically through a restriction. A larger throttle body on a J series motor WILL NOT hurt your power. The way to utilize it further for more horsepower is through a better intake system, port matched intake manifold, and upgraded exhaust system.

You are right though, someone on forced induction would certainly see a benefit for doing this. Personally my main reason for this, I am awaiting the Comptech Supercharger kit that will be released later this year. I am making sure my intake is properly set up for the extra air. But I also believe this will benefit N/A even if it is a little. It just depends on how far people want to stretch their money.

 

I get my parts all back this wens, I'll be at pure tuning this friday afternoon. I'll snap pictures and take video. We will see who will have the "FOOT IN MOUTH" about horse power gain,me or the doubters! Search Mustang dyno to see my old numbers.

 

I was unaware Honda still uses MAP. I'm shocked. Learn something everyday.

When it comes to stability/traction control, the throttle plate plus other engine functions are manipulated by the motor. That's why stability/traction control systems can't work on cable throttles.

 

What misinformation am I spewing? You're not going to gain power from this mod. The TB is already plenty big and it's not a restriction. All you're doing is fooling the TB and ECU into thinking you're giving it more throttle. It works much like that silly Sprint booster.

I know I'm right about the drive-by-wire TB being manipulated by stability/traction control system. They all work like that. I'm just giving you guys a heads up that messing with the TB size could possibly have a disastous effect on the stability control programing. Those programs are finely tuned to the TB, yaw sensor, accelerometer, wheel speed sensors, and steering sensor. It is quite possible that changing the TB size could actually cause the ECU to send the incorrect thottle postion value to the TB which could cause a loss a control which is the very thing it's trying to prevent. Just something to consider.

 

I guess they're not expecting FI apps on their vehicles so in the spirit of cutting costs.. at least the RDX has a MAF .. yeah.. the TCS operates via the ECM feeding off of the wheel sensors to decide when to cut throttle. IHC is probably right that it won't make much of a difference once driving style is adjusted.

 

Telling people that there is a MAF and that disastrous events could occur is what I consider this misinformation. Simply put, you are incorrect on both parts.

 

It's a bit primative, a modern car using a speed density setup. Really, we are at a disadvantage the second we start modding. All those dead end turbo threads would not exist if we had a MAF setup.

I also assumed the TL used a MAF system until I popped the hood for the first time. I would guess over 90% of new cars are MAF.

And for the record, the stability control will be altered with the larger throttlebody. That extra low end and responsiveness that you feel will also show up when the computer is trying to help maintain control of the wheels. Whether it will be enough to have bad consequences has yet to be determined.

 

I think people most often mistake with the VSA system is that it is almost entirely dependent on the throttle, this is incorrect.

"VSA® works in conjunction with the vehicle's drive-by-wire throttle and its 4-channel ABS system to help the vehicle maintain the driver's intended path of travel. It functions by applying brake force to one or more wheels independently while also managing the throttle, ignition and fuel systems to reduce engine power output."

Reducing the throttle is only a small part of what goes on during a 'disastrous' event. In testing this with bored throttle bodies on drive-by-wire systems along with removing the first throttle body used in the earlier VSA systems on the 2G CL/TL, if the car tries desperately to cut throttle and does not see the expected reaction, the car falls into an ultra safe limp mode reducing the cars power almost to nothing. This only happens when you are trying to mash the gas pedal and lose all traction. I'm not sure why you would want to do this in a 'catastrophic' event anyway, but needless to say the car remains very safe in either situation. To get the car out of limp mode, you must turn it off and turn it back on.

Again... people have tested these things out and manipulated these cars. I wouldn't make this stuff up, but everyone of these car buffs just assumes things while I try to keep explaining that others have been through all of this before.

 

Ummmm yeah....already I said that, but you claim I was wrong. Old school traction control systems simply used the ABS unit to control spin. DBW systems use both throttle and the ABS/wheel sensors.

I could care less about traction control. The worst that can happen is you get stuck. Stability control though is very complicated. So you're telling me 3rd gen TL owners have tested these enlarged TBs in all sorts of loss of control situations to verify everything still works? 50mph on a rain/oil slicked road? Ice and snow? I find that hard to believe because it sounds like this mod is still pretty new to these cars.

Also, don't twist my words. I've NEVER once said this mod would definitely cause a problem with the stability control system. I said it was a possibility.

 

+1

Too bad some choose to knock some of the resources in this community. I think Dave has been recently referred to as a douche bag and badgered on other threads. I would like to think we are all trying to help each other by pointing out various concerns, characteristics etc. No one is 100% correct, but a few folks are going out of their way to educate and share their experiences at no cost to the younger guys.

 

I guess those new numbers were nothing to run home and post about. Imagine that.

 

Did a diy this weekend so ill post dyno numbers this week. So go funk your self with your comment

 

Aww...somebody's got his panties all in a bunch.

 

^^yup grandma panties.

 

Any updates? I guess those mods never panned out like you planned.

 

Why dont you look under the Factory Spacer? Takes a big man to with small balls to bash someone through the computer.

 

Yea, I've been following that thread, and I didn't see any dyno graphs from you.

You think I'm bashing you? Wow.

 

updates?