Golly!... Guess it's I'll just live with it.

 

Yes...but and it's a big but...but who really cares how fast their car free revs (in neutral/clutch in)? If in a like for like comparison the car with the gears undoubtedly accelerates faster. I wouldn't refer to the gears as "masking" as they are one of the key elements to help make up for the throttle to acceleration lag handicap.

More air in & out and less rotational mass with a gear that puts you higher in the RPM band... because faster acceleration is what matters most either way.

 

Any recommendations for where to get a ported polished throttle body. I’m in Pittsburgh pa. Thx.

 

Yes, true. In the days dating back to carbs and cable controlled throttle bodies, gears were the way to go to simply get faster acceleration. The downside to gearing is that you lose top end speed, running consistently at higher rpm at normal speeds, and as result reducing fuel mileage.

 

The TL;DR of the answer is: It matters. First, you will actually see higher horsepower numbers with less rotating inertia. Not a ton, but there is a mild improvement. People have done dyno tunes before and after switching from a ~55lb clutch to a ~25lb clutch and seen mild improvement there. Second, and time you rev match, you're blipping clutch-in, and you want a good sharp blip, very predictable, which is easier with less weird. Of course if you go to the heavy-weight extreme you'll feel like the entire system is dragging. Vice versa, if you go to an absurdly light-weight extreme, you'll end up with something that's only useful on a race track. Which is of course not a problem since the light-weight extremes are targeted towards race car use.

GM optimized this car to be easy to drive and hard to stall for rank amateurs who have bad habits and refuse to learn. You can knock off 30+ pounds from the rotating assembly and improve breathing and end up with a car that's a lot more engaging, at the cost of being weirder to drive for anyone who's not used to it.

 

We are talking about cars here with a top end speed of about 180mph. Losing a few mph on the top to make up for lag at the bottom (street operating speeds) is an absolute benefit. And this where 99% of C5 owners drive their cars. Impact on fuel mileage is minimal with a gear swap.

Its not like the C5 with 2.73 gets 15 more miles to the gallon than a C5 with a 3.42. So going from 3.42 to say 3.90 or 4.11 isn't all of a sudden going to cost you a massive amount of MPGs. That's just not true. Fact of the matter is ...the MPGs go down when people have more fun driving their cars.

 

I've gone a few different routes on builds over the 23 yrs of C5 ownership. My brothers have also owned C5s for 20+ years. So we've had a few test subjects (5 to be exact) that we've played around with making changes mostly to the specifics of each of our likings. None of our cars were purchased, built or intended for any driver but ourselves. So yes, our cars will perform differently (better in every way from a performance persepective) than the mass produced stock C5 with grandmas, grandpas, teens and average age adults in mind as being a "one size fits all".

We've done 3.90 gears, 4.10 gears, stock clutch and flywheel, light clutch and flywheel, assorted heads, assorted cams, different exhausts, 12+ different sets of tires, ported TBs, 6 or 7 different cold air intakes, prochargers, different shifters etc..

Not one of us struggled to drive one another's cars. In fact...my 74 yr old dad (RIP) enjoyed driving my H/C/I, 4.10 geared, light weight clutch and flywheel set up more than any of the other cars we had. Including an axle back, otherwise stock '99 coupe and a 97 Viper.

Making most of these upgrades don't all of a sudden render these cars difficult to drive or terrible on gas. Yes "extremes" can and will do this, but there are countless directions one can go in to improve fun factor 2 fold without sacrificing any of that driveability whatsoever.

This string started based on the debate over throttle devices to "improve" throttle response. Which in my opinion making my throttle more like an on/off switch is counter productive in every way. I want linear acceleration at all times. It's easier to control at launch, more pleasurable to drive leisurely, and it's easier to drive at speed.

Go on YouTube and look at videos where throttle devices were tested against draggy times. Not one driver gets a better time with the device installed. They now struggle to find that linear throttle control and can't launch their cars without spinning. All things that you can still more easily control with a linear throttle.

 

I think the problem is these people believe that the dbw throttles + ecu are limiting/delaying their throttle input. I haven’t been able to find any testing/info showing that to be the case.

I suspect most or all of the people complaining have auto transmissions and part of the issue is how the transmission tuning/shifting reacts at various throttle inputs.

 

I totally agree. The complaints always come from the A4 guys. Many of which are looking for a $150 quick fix. (Not picking on OP here. As he is one of many with this dissatisfaction towards the A4 C5).

Fact of the matter is...there is no quick fix for under $200 for the A4 C5. Especially with a 2.73. You need to tune the car at a minimum. But if you did both the TB p&p and tune with a 3.42 diff swap your car will be exponentially more fun to drive. All without breaking the bank, completely molesting your car, or making your C5 a gas guzzling monster.

 

Buy some heavier shoes.

 

I had my OEM TB p&p by my local machine shop/ engine builder. There are places like SoCal porting and others that do this for about $100.

No need to go with an expensive after Market TB in my opinion. The OEM TB with p&p is very capable. I've used my p&p OEM TB on all of my builds. Including H/C/I and procharged. It's still on my car as of this very moment.

 

Just For The Record; I owned/ own both a mn6 & A4 Both suffer from response issues. Again; Not gearing or transmission induced. It's ECU/DBW throttle control only not drivetrain. Other owners may or may not understand or notice the effect but it is there.

Acceleration matters but how it's developed is gold. A computer that electrically opens a throttle is always going to slower to rev than a cable. That's what I meant when I said put it neutral. Independent of ratios. It's the ECU/DBW throttle that doesn't respond as efficiently as a cable throttle is more the message
The idea of response and flat out acceleration is kind of being blurred, partially misunderstood. Also the big Gorilla in the room is Torque. Torque spins the tires and moves a heavy car. But, take V8; try and make more HP. 9/10 guys add power by stealing usable TQ and pushing more air and fuel at higher RPM's which is also where and why A LOT of guys go for the 4:90's. You end up forcing the car to rev higher and sacrificing power it used to make at the normal range.
Sure a high geared car will use the mechanical benefit to accelerate harder more easily but it still won't make an identical geared DBW car accelerate as fast as cable throttle. The ECU is stealing faster response from any motor that the motor is capable of producing, IF it were allowed to open the throttle faster,wider and sooner than it is programmed. That's all

 

Increasing throttle response isn't Voodoo. It's not a light switch either. It could be if you don't understand it and how it works and incorrectly modify the car. I'm know it's not going to change your theory on life but I've used 3 signal amplifiers on different cars and all made them easier and more fun to drive. Don't knock it until you try it but I get that with some OG applications it may be difficult to be cohesive in the same manner adding a blower on a car may effect how it accelerates and need to tailored to that specific car

 

I vote for Soler Performace. They have a stock LS2 silver blade, port and polished, plug and play. If that is something people are interested in. I have never felt a throttle lag. I have a manual though.

 

If you swapped your throttle body for a cable driven one you would have virtually the same throttle response. If you know of any testing showing the dbw LS throttle bodies have any noticeable lag/delay compared to cable I’d like to see it.

It’s very possible there’s throttle response improvements to be had with tuning, but not because of dbw

 

HPtuner has multiple files on % rate increases in throttle input

This isn't just a single Company attempt. There are others out that help with DBW Throttle lag
Absolutely don't take just my word on this

11-01-2013 #4


"99 Corvette with the stock ECU. It has had this throttle lag "
Owners own post

https://forum.hptuners.com/showthrea...ottle-Response

 

why did you cut off the rest of that sentence?

“99 Corvette with the stock ECU. It has had this throttle lag every since I built the 6.2L race motor with the 90mmTB and 233/239 cam”

Sounds like no lag before

 

What happens if you change those % increases in throttle input past what the TAC module expects or can interpret? I'm no expert but in HPT those are the only tables it warns you against changing. It can make your TAC module inoperative it warns. Imo it doesn't have any more lag than my 2016 infiniti which has two throttle bodies and way more electronics.

 

You have a nice paperweight

 

I understand throttle responsiveness. I've owned 20 or so two stroke dirt bikes 125, 250 and 500 cc. Nothing responds like a two stroke.

So now you've agreed that the gears will in fact "mechanically" (as if semantics matter) accelerate your car faster. You can test my gear theory yourself with a geared pedal bike. Same rider, same physical capability, which gear will allow you to propel yourself forward with more acceleration under the same power?

I never said there isn't a lag with DBW. I'm saying there are absolute ways to improve upon this with the correct modifications that don't include a pedal device. All of which play a role in making the stock C5 a better performer.

We aren't comparing cable vs. DBW with the C5. The C5 is only DBW. Therefore we are determining how to get the DBW handicapped C5 to accelerate faster. Gears will 100% have a positive impact on ET's. Pedal devices have yet to prove to be able to do this.

You have and do own both an MN6 and A4. What modifications have you made to improve the performance of your cars? Were they mild, wild or mostly stock? After these changes were made was your car still as lacking in responsiveness? If the answer is yes, you need a better tuner, more go fast parts, and a gear. Otherwise your basically stuck until you or someone invents a C5 pedal device.