I hooke dup autotap and saw that when i am flooring it, my throttle position reads 100% but my TPS voltage was at 82.5. I did the throttle body bump stop mod last night at around 11pm using Autotap. The TPS voltage it was reading was 89.4* and 89.8* which is near perfect (90). Actually too close to perfect. This was done with me inside the car actually pressing the pedal all the way (car was off).

But here's the thing. I went for a run right now just to see what some parameters are when at WOT and even though the throttle position was at 100%, the TPS would read a max of 84.4 and would be different at every speed. Can anyone shed some light on this problem?

 

sounds like a bad sensor <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

No, it's not necessarily a bad sensor. Stop and think how much money a true race car costs with high performance computers, and extremly sensitave sensors. Now consider how much your car cost. One of the ways that all car manufacturers keep costs down is by using equiptment and computer sensors are included that are not that extremly sensitave. A great example of this would be the speedometer. The disclamer on any speedo is + or - 3 to 5 mph. It's not exact, but it's close enough to give an idea. Same with the computer sensors. Trust the reading that you got with the car off and not moving, you don't want to hit 90 degrees and create problems.

 

Well, I found out what the problem was... The carpet was underneath the pedal and I couldn't press it down all the way... <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> that would explain it hehe.


By the way, this mod is great. I manually opened up the TB and i mean this thing was sitting parallel to the ground.

I just have one question, since I can push the throttle in more, does that necessarily mean it gives my engine more throttle? Or does it just stop the impediment of air flow?

 

What do you mean when you ask "Does it give my engine more throttle"? Of course it gives it more throttle. That's why you did the mod in the first place. The question is what does "more throttle" really mean? More throttle used to mean more fuel when you were using a carburetor. Now your using a TPS, MAF, MAP, IAC, IAT, PCM and a Throttle Body, so what do you mean by "more throttle"? The definition has changed. When you crack your throttle open what is really going on?

 

Well, this is how i understand it: the more you push the pedal in, the more fuel that goes into the engine. So since i can press the pedal in further, does that mean more fuel goes into the engine?

 

The pedal was already all the way to the floor. The throttle blade not opening fully is the issue. By doing the TB bump stop mod, air flow is much more straight and less turbulent. That is where the benefit lies. I doubt it allows much more air to actually enter the throttle body. FWIW, this mod cut 2 tenths off my ET.

 

I sorta felt a difference with this mod too. Hopefully it'll help me break into the 12s <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

2 tenths? That's like 20 hp.....did you actually confirm this at the track?

 

Well, I can't specifically say that cutting 2 tenths was directly the result of the TB bump stop mod. My car was still running mid 13's when I did it. I believe I went 13.4 one week. I did this mod and went 13.2 the next week with roughly the same weather conditions and the same 60' time. I believe my car had a very hard time breathing right from the factory. I went from a 13.6 @104 to a 13.0@107 all with 2.0 60's just by modifying the intake (lid, !FRA, TB Bump Stop Mod) and a catback.

I really didn't gain 20hp. I just worked out the bugs. The car already had the power in it. I freed up the hp a little.

<small>[ February 09, 2003, 08:03 AM: Message edited by: camaro_ls1 ]</small>

 

2 tenths is a pretty big deal on a 13 sec. car so if you got that kind of gain you did quite well. When you crack your throttle the engine pulls more air. So when you say "more throttle" your saying give me more air. The PCM detects this sudden lean condition very quickly at the pre cat O2 sensors. The PCM is going to try to maintain your A/F ratio at 14.7:1 so the PCM increases the pulsewidth to your injectors. You might have a fatter A/f than that if you have LS-1Edit, but the basic operation is the same. The PCM is like an ARBITRATOR with the TPS, MAF, MAP, IAT, IAC, etc. all SCREAMING for attention and the PCM has to decide which device is the most important and who gets to suck the nipple first.