Vortec Throtle Response Boost

[NacIK]

This is an easy way to add a little more responsiveness to your throttle. On the vortec engines there is a restriction plate on the throttle blade. You can see it by holding it at WOT. This plate is held on by two rivets on the throttle blade. When you step on the gas a little the air can only flow over one side, and at WOT it restricts it a little bit from head on. The aftermarket throttles have this restricter plate already removed. I have found a cheaper way using the stock throttle to do this:
Remove the throttle from the intake tract.
Flip the throttle upside down on a flat surface.
Drill out two the two visible rivets that hold the restricter on.
Carefully pry off the plate from the throttle blade.
Clean loose metal shavings and debree from the throttle
Install two rivits in the two holes just made from the removal, flat side on the top of the blade.
Optional: Use Dremmel or similar product to smoothen the rivets.
Reinstall the throttle assy. and have fun!

Good luck and ask me if you need further instructions.

[CodyZ71]

how much of a difference?

[AcrophobicChevy]

^^^what he said

[AcrophobicChevy]

bump
i wanna know a little bit more bout this

[NacIK]

It does help out alot on the low end response on my vehicle, but it could also depend on the setup. I have removed my void box (the box on the intake that says "Vortec") and also have headers and true duals. But I have seen a lot of good reviews on the aftermarket t.b's and this mod is basically the same thing; It flattens out the throttle blade at WOT. I wish I had took pictures though. It probably would have helped.

And there is nothing wrong with a free mod!!!

[NacIK]

Do make sure though that you plug the two holes created by removing the rivits with something. If not then your idle rpm's will go from 600 to 1100. As an experiment I tried reinstalling without the holes plugged and it feels like driving it with a wild cam and a stock t.c. You will wear out the breaks quickly and fill up often!

[dubwise]

I noticed a difference in throttle response when doing this mod... CFM-Tech offers an after market throttle blade for those who do not want to mod this themselves:

http://www.cfm-tech.com/chevy-vortec.htm

[cooker2003]

In my experience, low throttle shift points were significantly lowered after doing this. WOT and mid throttle points were not affected, but off idle (low TPS positions) the trans upshifted way to early.

Also, the linearity of the power/pedal feel went from being a progressive increase in power throughout the pedal travel - to pretty much an on/off switch. After about 1/2 throttle the engine did not respond (produce any more power) nearly as significantly as it did stock. I put my plate back on.

[AcrophobicChevy]

cool deal...mixed reviews! thats what i wanted...btw cooker2003...nice rollpan i havent seen that with them spaced so fatrout...i like!!!

[tahoehtp]

I did this today, I just cut the lips off with grinder and smooth out the edge I cut so I don't have to re revet the holes.
mine without a woid box, air box opened with RAM hog filter.
it did have better throttle response, and like cooker2003 said not much on lower part response. but did notice the difference without it.
and like it :)

[cooker2003]

Originally Posted by AcrophobicChevy

cool deal...mixed reviews! thats what i wanted...btw cooker2003...nice rollpan i havent seen that with them spaced so fatrout...i like!!!

Thanks man. They are placed in about the only spot that I could physically fit the exhaust pipe through....the routing is pretty tight! I just got out the hole saw and went to town...

On topic, has anyone else had the same results as me? Maybe I am just very anal in noticing the lower shift points, etc.
Dave

[tahoehtp]

yeah for me I didn't drive much today so it was hard to tell, but as far as the lower gear yes I noticed the difference it did shift early. I'm going back to long island from upstate NY tomorrow so I'll see if there is any differences in upper gear. and see anything different in putting pedals down.

[04SilveradoMykk]

I did it on my 4.3L a while back, it created mine to bogg down with hard accelerator from a stop. Right off of idle was the problem, but once it picked itself up it was fine. I replaced the restrictor plate and no problems. I might cut the plate in half however, that might be an improvment.... I always looked at that restrictor plate as GM's modern day version of the old quadrajets, tiny primary valves and HUGE secondaries.

edit: plus, without the restrictor plate my TB spacer stoped whistleing... with the plate it whistles. haha

[tahoehtp]

well back to long island, I did onticed that early shift. on 1-2. because I have bang prob and it was doing it before 10mph. usually around 13 to 15.
and yeah on highways when I step on the gas, it does goes but didn't see much difference. but from 2-3-4 I felt more power in especially in 3rd when accerating.

[JoeliusZ28]

Originally Posted by cooker2003

In my experience, low throttle shift points were significantly lowered after doing this. WOT and mid throttle points were not affected, but off idle (low TPS positions) the trans upshifted way to early.

Also, the linearity of the power/pedal feel went from being a progressive increase in power throughout the pedal travel - to pretty much an on/off switch. After about 1/2 throttle the engine did not respond (produce any more power) nearly as significantly as it did stock. I put my plate back on.

If you think about what youre doing to the throttle body its fairly obvious why this is. Removing the restrictor plate allows more air to flow through the TB at less throttle. Even though you might be making the same power with less throttle, the trans still thinks youre giving it less throttle because of what the TV cable is inputting to it.

I personally think the low-throttle shifts are late on my truck and I also dont like added linearity of the restrictor plate. It tires my leg out FAST on trips, whereas my old truck (TBI) had no restrictor plate from the factory. low throttle shifts were more positive and my leg never got tired even without cruise control. You also mention no further power being made after half-throttle... my truck feels that way already even with the restrictor plate. 2/3 feels the same as full, with the exception of the trans hesitating a bit more.

Im going to try this mod later this week. Ill start by shaving down half of the plate, see how I like it and post the results. I have a feeling though Ill be removing it altogether. Ill be honest the reason i want to do this mod IS to remove the linearity on the gas pedal and lower my part throttle shift points. I really dont see much of a power benefit coming from this.

[popo]

i just did this mod as well as a port and polish tot he throttle body and it has awakened my V6. I have felt a huge difference off the line.

[NacIK]

Originally Posted by JoeliusZ28

Ill be honest the reason i want to do this mod IS to remove the linearity on the gas pedal and lower my part throttle shift points.

That is more or less what I have noticed reciently on my vehicle. Way better that what was planned!

[N0DIH]

A friend of mine has this "mod" and although it does seem pretty responsive in the low end, it changes the shift points, so the throttle is backed off, and shifts are different and TCC apply is also different, and quite annoying.

If anyone has the part they took off from this mod, please send it to me, I want to switch his back. The converter shudders bad because of it.

[96c15004.3]

I would try this but in California I have to go to a test only center do you think
they would notice I did this on my 96 1500

[N0DIH]

This shouldn't have any effect on emissions (maybe, if anything, EGR, but minor).

I would say no, they won't catch it, nor should they care. But I don't know the detail they go to in a emissions visual inspection....

Personally, the drivability issues on my friends truck, I wouldn't do it, or I would mod it back. Still goes, anyone got the leftover part still?