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Overkill Throttlebody upgrade?

13K views 39 replies 13 participants last post by  Joes74challenger 
#1 ·
Planning on ordering up the Overkill Throttle body upgrade as soon as I'm done with my truck project. I was wondering if anyone else has put the 80mm throttle body on and what their thoughts were? I've currently got the CAI and Overkill Tune (which is AWESOME!) The car definitely is definitely more fun to drive! I would recommend the Overkill tune to anyone thinking about getting it.
 
#2 ·
I've had one reported double digit horsepower gain, will be having a Camaro customer dynoing before/afters soon.

The 14+ Impalas have a distinct advantage over the 12-13 Impalas or 12+ Camaros; if you go to my website you'll see the pic of the intake manifold that's already 79.5mm, that's the 14+ Impala manifold. So basically, the larger throttle body is a perfect match to the existing inlet, without porting required.

Also, when you look at the intake manifold, you'll see the throttle body is mounted on an upward slant. In doing this, because the throttle blade sticks out the back of the throttle body about 1/2", it actually blocks part of the throat of the intake manifold where the airflow is entering. By using the 1/2" adapter plate with my 80mm kits, not only do you get the size increase, but the adapter plate effectively moves the blade out of the intake manifold throat so it doesn't choke off the airflow.
 
#4 ·
That's great to hear! I'm planning on ordering a new throttle body this month as well!
 
#5 ·
PX...


I hope I'm not insulting no one with this reply, but, some of you 9th Gen really need to start looking at the 8th Gen discussion. We've been modifying the LFX engine with success for a few more years! LOL


To answer your question, YES, the 80mm TB (and the JacFab spacer) is absolutely worth it and are performance improvements.


http://www.impalaforums.com/8th-gen...yno-test-report-overkill-80mm-tb-vs-vmax.html
 
#14 ·
So I have the Overkill 80mm throttle body (not installed yet) and am waiting for the cold air intake to arrive in a few days. Also waiting for the Tune files from Will.

I have a question regarding the throttle body, mine did not come with any sealant and was wondering if any is even needed?

1FastImpala

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#16 ·
Ordered my Throttle body today. A little later than I wanted to do. The wife made it one of my Christmas presents lol
 
#18 ·
Ordered mine as well for the same thing, Xmas gift to myself :) should have it by Friday.
 
#19 ·
Hey Juleshaw- have you put yours on yet? I'm about to do mine today. Just warming up the garage as I don't freeze my wimpy fingers. Looks pretty cut and dry. 4 bolts to remove, then put the spacer on and then bolt the new on on. I'll do some pics as I go thru it in case anyone wants to see how it goes.

Overkill- is it ok if I send you the tune I'm using and you mod that?


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#20 ·
Ok, so I installed my throttle body. It wasn't too bad to install. Seems like the throttle response is a lot better. I have yet to take it out on the road as it's sitting in the garage waiting for the nice weather to return. Here is my pictorial of the install.
A quick side note: I don't care for the location of the plug on the new throttle body. It's a lot closer to the firewall and it wasn't much to move. I would have preferred the same location, but oh well.

So after popping the hood, you'll need a 10mm wrench to remove the cable off the negative post.
Vehicle Auto part Car Engine


My impala has the Overkill PSI on it already, so all I had to do was unplug the MAF and just move everything out of he way. I did not have to remove my heat shield.
Engine Vehicle Car Auto part Hood


Unplug the electrical connection to the original throttle body before taking a 10mm socket to remove the 4 bolts. Because I have the rubber adapter on my throttle body, I could. It get all the bolts out. So I just got them all unthreaded and pulled it off with the bolts.
Fashion accessory Auto part Metal Locket Compass


The spacer goes on with the o-ring facing out. Using he (4) supplied screws, you will need a 5mm Allen wrench to secure the spacer. Do not over tighten!
Auto part Engine Automotive exhaust Automotive engine part Exhaust system


Before attaching the throttle body, plug the electrical in and just check for fit. I made the mistake of putting all the bolts into the throttle body and 3 fell out into the engine compartment and one fell into the intake! I was able to retrieve them without too much effort but save yourself the aggravation and put them in 1 at a time. Do not tighten until all the screws are in place. You will find it easier to loosen the tubing that runs next to the throttle body so you can tighten the bottom front screw. This can be achieved using a 10mm socket which you should have already for disconnecting the battery.
Auto part Engine Fuel line Automotive fuel system Vehicle


The head on the clamp to mount the intake back on is facing down on the back side. I could not relocate it. Remember, you cannot put the stock intake back on the car with the overkill throttebody.
Engine Auto part Vehicle Car Automotive engine part


I connected the battery and started the car back up and rev'd it up a few times and it feels different. I won't know until I can get it out on the road. Aside from the new ply location and the worm clamp screw location, this was a very easy upgrade. My hats off to Overkill for this great upgrade. My next project is the spacers.



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#21 ·
Just finished putting mine on the 23rd lol. Lots more throttle responce. More power everywhere it seems. Engine is deeper, exhaust is deeper. Everything is better
 
#22 ·
Boy, I just looked that posting over and I have a ton of typos lol. How can I edit it to fix the typos?
 
#23 ·
Should be top right corner....
Are you having any cold sytart issues? When I start my car and it goes into high idle for warmup, revs sumtimes bounce 1000-1500. Acts completely normal once idles down. Warm start ups are not a problem. Seen somewhere else that the 80mm tb can cause cold start idle issues, untill tuned out.
 
#25 ·
I took it out yesterday and had no issues. Very responsive and a little more throaty.


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#26 ·
Yep. More throaty. More pull from any RPM, all around feels faster... just still having that cold start high idle problem which goes away after 5 second of idle lol. Sending Will 3 scans today hopefully fix the problem and ill be tuned for the 80mm
 
#27 ·
No cold start issues. I drove it to work today. Started fine in the heated garage and when I left today it was only 12°F out. It started fine. Sure is fun on the freeway! I can feel a difference for sure. Looking forward to getting my tune updated. Hoping Overkill recovers from the holidays and gets it back out to me soon lol. I will most likely order the spacers before the month is over.


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#28 ·
Lucky you hahaha. Still having idle issues. Might be from the 80mm and the horsehoe bend delete together idk? Still only on my base tune.
Waiting on my revised tunes from Will aswell, I'm also going to pick up the spacer next pay, maybe the SLP UDP in the future as well, hoping they make some highflow downpipes for us 9th gens soon. TB really helped low end and mid range it seems and the spacer gives bigger gains. Cant wait lol
Very surprising fast for a v6 in a 4000lb car
 
#31 ·
anybody can do this. Pretty sure the bolts are 10mm if not 8mm on the stock.. supper easy. Honestly easier than an intake
 
#30 ·
It really is as simple as unplugging the electrical plug, removing 4 bolts, then bolting the new unit back on.
 
#33 ·
It is a drop in replacement BUT if you do not tune it will likely screw up the fuel air mixture. You will see a bigger performance gain from the tune to start with anyhow. If I were you I would start there. Also Overkill offers re-tunes for free when you add on pieces, so it would not go to waste getting it first. If you just want a little kick in the pants and some extra horsepower you can look into Trifecta tuning also as they are a bit less expensive. Trifecta however will not at this time support any extra modifications and is designed for a stock vehicle.
 
#35 ·
Any issues with the Overkill Tune?

Looking to upgrade my 2015 2LTZ. Have you guys had any issues with the performance / wear and tear on your cars since you did the upgrades?

Im looking to do the tune, 80mm TB, and intake.

Love the car stock; looking to add a little something for highway driving. Let me know your thoughts...
 
#36 ·
Looking to upgrade my 2015 2LTZ. Have you guys had any issues with the performance / wear and tear on your cars since you did the upgrades?

Im looking to do the tune, 80mm TB, and intake.

Love the car stock; looking to add a little something for highway driving. Let me know your thoughts...
Mines perfect so far. I'm at 72000km.. had the overkill as I since 25000k...
So far I have~~~~~
Overkill Intake, 80mm overkill TB, JacFab 3/4inch manifold spacer, overkill 91 octane tune, horseshoebend delete (y-pipe), 3rd cat delete, Res and mufflers deleted, also have an EE catch can.
I burn maybe .5l of oil over 5000km with lots of 7k rpms. Car is a different animal now. Pulls 2x as HARD. Reaches 200km/hour no problem.
 
#40 ·
the seat of the pants dyno says it's beneficial for usable power (seems to move the torque band down lower to say 1500 rpm on a 3.5). it took two months to get the files back after i had to badger the guy repeatedly but the 87 octane tune so far has been nice. i plan to use the 93 octane tune on the next fillup.
 
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