Thoughts on this "Stage 1" before adding Whipple during "Stage 2"

ralphsmithiii · December 7, 2019

Hello everyone,

I've been lurking here and there as the owner of a 2018 5.3 Z71 1500 SIlverado. Currently the truck has a Carven catback and is tuned using a custom Diablo tune. Although it helped a ton with the transmission shifting, the truck lacks enough torque for me as a daily to consider it a "fun" vehicle to drive. I also tow with it every now and then, around 5k-6klbs and it's been pretty reliable all the way around. With that, I'm ready to do some upgrades in hopes of obtaining more torque for my own personal tastes.

Currently what I've been spec'd out is the following and we'll consider this is a full "Stage 1" bolt-on setup:

Headers + y-pipe - Was/are considering TSP 1 7/8s and cat-less pipe (I'm in Florida but I'm debating/wondering HOW bad the gas fumes will be without using the hi-flow catted pipe). However, Kooks is having a 20% sale this month and while that still puts it close to 2x the cost, I may go this route for fit and finish and overall sound.

Cold Air Intake - By....CAI. Nothing special here, just looking for more air in because of the next "Stage 2" mod of adding a 2.9L Whipple.

E85 - Flex Fuel Kit by DSX - I know you can make a "kit" for cheaper, but I've used their kit before on another vehicle and it was hassle-free and easy to install.

Re-tuned by HP Tuners (Engine/6-speed trans).

AFM is currently disabled and will stay that way. Truck is leveled on 33's (I am looking to lift it, some, eventually. Maybe a 5" kit down the line).

I don't/won't drag race the truck, I'm just looking for a more enjoyable daily driven experience. I've considered trading it in for a 6.2 or checking out, um..."other" offerings. But, I like the truck and money wise I think some bolt-ons for now would do the trick to satisfy the itch to modify while giving me some more torque than what I currently have.

This "Stage 1" is something I'd like to do this month or maybe Jan 2021, depending on what goes on sale when. The header sale is what while hold me back in terms of getting it all in and installed before Jan 2021.

Lastly, this stage is the pre-requisite to adding in the 2.9L Whipple and calling it a day. At this time, I have no desire to go further than that with the truck.

Any thoughts on this first stage go-around of mods? Essentially when it's done it would be: CAI, headers + y-pipe, cat-back exhaust, flex-fuel for E85/93 + tuned on HP Tuners.

Additionally, I believe I read somewhere that with these trucks, if you add boost (Whipple in my case) and expect to run E85, you'd need to upgrade the fuel system (LT4 pump and other pieces?). If that's the case, I'm still leaning towards running it now since it's readily available in my area, I don't care about MPG, and I've run it in the past 3 performance car's I've owned with nothing but gains with the fuel + proper tuning. However, I'm not sure if it makes sense if I'll have to run 93 when adding the Whipple as I don't think I'd want to upgrade the fuel system unless it's REALLY worth it on the stock block/trans.

Jacoby · December 8, 2019

If you’re gonna put a blower on it and try to run straight E then you’ll definitely need to upgrade the fuel system. You might be able to get away with mixing with 93 to bring the alcohol content down but even then I doubt it.

you should just gear it and call it a day

2003 SSEi · December 11, 2019

Ralph, im in a similar boat as you. I tow a enclosed 24 foot car trailer in the summer that weighs in at right around 8,500lbs. I have the Volant intake and a Corsa Catback tuned with HP tuners. Towing in the Mountains of PA and heading over and thru Michigan, the 5.3 left me wanting more. My truck is mainly a Tow Rig and hauler for me, as its not a daily driver.

As far as the headers go, I have seen many trucks with the stock exhaust setups make great power. I have thoughts of adding headers, but with the Corsa and adding LT's it might make the truck really loud, and that is at least a concern for me with the towing I do. Its already loud with the Intake noise from the Volant and the Corsa under throttle pulling the trailer.

I also have no plans to drag race the trunk.(My Car makes 600 wheel) soooooo that being said I actually ordered a 2.9 Whipple while they were having a 15% off Black Friday sale. I wanted the added TQ and HP that the Whipple will give to the truck even on Pump 93

ralphsmithiii · December 11, 2019

On 12/8/2019 at 1:30 PM, Jacoby said:

If you’re gonna put a blower on it and try to run straight E then you’ll definitely need to upgrade the fuel system. You might be able to get away with mixing with 93 to bring the alcohol content down but even then I doubt it.

you should just gear it and call it a day

When you say, "just gear it and call it a day", do you mean specifically to skip all the bolt-on's and swap from a 3.42 to say 4.10's?

ralphsmithiii · December 11, 2019

21 hours ago, 2003 SSEi said:

Ralph, im in a similar boat as you. I tow a enclosed 24 foot car trailer in the summer that weighs in at right around 8,500lbs. I have the Volant intake and a Corsa Catback tuned with HP tuners. Towing in the Mountains of PA and heading over and thru Michigan, the 5.3 left me wanting more. My truck is mainly a Tow Rig and hauler for me, as its not a daily driver.

As far as the headers go, I have seen many trucks with the stock exhaust setups make great power. I have thoughts of adding headers, but with the Corsa and adding LT's it might make the truck really loud, and that is at least a concern for me with the towing I do. Its already loud with the Intake noise from the Volant and the Corsa under throttle pulling the trailer.

I also have no plans to drag race the trunk.(My Car makes 600 wheel) soooooo that being said I actually ordered a 2.9 Whipple while they were having a 15% off Black Friday sale. I wanted the added TQ and HP that the Whipple will give to the truck even on Pump 93

My truck with the Carven exhaust system sounds really good as it sits. I've had headers on my Vettes before (Kooks on the last one) and it does step it up quite a bit in sound, more so coming from the engine, of course. I'm not sure if that's something I want in the truck being it is my daily driver and and I occasionally take calls for work when on the road. But, I can't say I've heard any trucks with just bolt'ons, no cam or blower so it may be alright.

With that, I also think that just adding the Whipple and running it on 93 is plenty enough to push the factory engine/trans as well as the fuel system. Although I'm a fan of E85, to spend the amount of money to upgrade the fuel system to support it with the Whipple may not make sense for my application. Same with the headers, sure more in more air out but with stock block, trans, fuel system, rear end, etc...is it worth it?

Also, there's another 15% Whipple sale coming up right after Christmas so I may have to go against my better judgement and buy it since I didn't pull the trigger during Black Friday =). Spend the $1.5-2.5k money for FBO+E85 on the Whipple instead, and see how that does?

Jacoby · December 12, 2019

32 minutes ago, ralphsmithiii said:

When you say, "just gear it and call it a day", do you mean specifically to skip all the bolt-on's and swap from a 3.42 to say 4.10's?

Yes that’s what I mean. Don’t get me wrong I’m all for adding boost when you can. I own a CTSV and more boost is key lol.

with our trucks it’s not the motor or lack of power that’s the problem. It’s the low gearing. A swap to a taller gear will not only keep your motor in the power band more often but it will ease the stress on the trans which is key for these trucks. A gear swap will make it feel like you gained a ton of hp and tq and be more efficient. Your mpgs will go up and towing will be a breeze. Strap on a blower and get to towing and you’ll be in the boost pretty much the entire time and your mpgs will go straight to shit all the while your stressing the shit out of the motor. And a gear swap will be waaayyyyy cheaper then your stage 1 and 2 by thousands of dollars. Just food for thought.

Either way you can’t go wrong with either option. They each have their benefits over one another. Good luck with the truck. Be sure to post up when you get to modding.

CombsL83 · December 12, 2019

Whipple includes their own intake system with their kits so don’t bother doing it before. They also say your truck needs to be on the factory tune in order to upload their programming but I guess if you have someone tune the truck with HPtuners you don’t need to use theirs.

ralphsmithiii · December 12, 2019

3 hours ago, Jacoby said:

Yes that’s what I mean. Don’t get me wrong I’m all for adding boost when you can. I own a CTSV and more boost is key lol.

with our trucks it’s not the motor or lack of power that’s the problem. It’s the low gearing. A swap to a taller gear will not only keep your motor in the power band more often but it will ease the stress on the trans which is key for these trucks. A gear swap will make it feel like you gained a ton of hp and tq and be more efficient. Your mpgs will go up and towing will be a breeze. Strap on a blower and get to towing and you’ll be in the boost pretty much the entire time and your mpgs will go straight to shit all the while your stressing the shit out of the motor. And a gear swap will be waaayyyyy cheaper then your stage 1 and 2 by thousands of dollars. Just food for thought.

Either way you can’t go wrong with either option. They each have their benefits over one another. Good luck with the truck. Be sure to post up when you get to modding.

Super helpful info, thanks a ton @Jacoby

For the truck newbie, I've read quite a bit about gearing and it seems that many people go from the 3.08 or 3.42 (which I have) to a 4.10. Does that seem to be the correct route for day daily driving and some towing? My understanding is that in the higher MPH's, I'd see a few hundred more RPM's but nothing to write home about. Plus, since it's 4WD, I'd need go get both the front and rear done.

Other than that, that may make more sense for what I'm trying to accomplish although I'm not opposed to gearing first then adding boost later the two don't go well together. The stage 1 is starting to look more like an option I'd pass for now and if I decided to boost it sooner than later, I'd probably do all of that at the same time to save some money on labor and tuning.

One small issue I have is finding a solid shop (so far) that knows how to regear these trucks. I'm sure there's one around but I'm 0/2 so far with ones that handle performance.

3 hours ago, Jacoby said:

Jacoby · December 12, 2019

10 hours ago, ralphsmithiii said:

Super helpful info, thanks a ton @Jacoby

For the truck newbie, I've read quite a bit about gearing and it seems that many people go from the 3.08 or 3.42 (which I have) to a 4.10. Does that seem to be the correct route for day daily driving and some towing? My understanding is that in the higher MPH's, I'd see a few hundred more RPM's but nothing to write home about. Plus, since it's 4WD, I'd need go get both the front and rear done.

Other than that, that may make more sense for what I'm trying to accomplish although I'm not opposed to gearing first then adding boost later the two don't go well together. The stage 1 is starting to look more like an option I'd pass for now and if I decided to boost it sooner than later, I'd probably do all of that at the same time to save some money on labor and tuning.

One small issue I have is finding a solid shop (so far) that knows how to regear these trucks. I'm sure there's one around but I'm 0/2 so far with ones that handle performance.

Gearing is going to depend on your tire size. With stock tire size going from a 3.42 to 4.10 would be like running a true 4.10. Going from a 3.42 to 4.10 and you got 35’s would be like running a true 3.42. There are calculators on this site and on the web that will give you an idea of what gearing you need for your setup. With 33’s a 4.10 would probably be just right for you. I have 35’s and a 7” lift so I went 4.56 and it’s great. Takes a lot of gear to spin those big heavy tires. Your rpms are going to go up but depending on how fast you cruise on the hwy it might not be that big of a deal. At 75mph I’m running about 2200rpm. With 4.10 and 33’s like you have. Rpms would probably be around 1800-2000.

yes since it’s 4wd you would need both ends regeared.

if you still plan to add boost I would probably not regear. Boost and talk gears would make it a horrible daily driver

as far as shops go. I would look for a dedicated off road shop, preferably one that does a lot of jeeps. My first instinct was to contact a “rear end place” or a transmission shop. I told them what I wanted to do and they acted like I was speaking a foreign language to them. One place even wanted to charge me $6k to do a gear swap because he hadn’t done a truck as new as mine and wasn’t sure what all was involved. He actually wanted me to pay him to experiment on my truck. Anyways I found a place that only worked on 4x4s called Dallas Off-road and on their site one of their services was gear installs. I called the guy told him what I had and he quoted me $2250 and said they would need the truck for 2 days and would provide a lifetime warranty on parts and service. The rest is history. Also if you have a 4wheel Parts location near you, they do gear swaps to. I was going to use them but their price was a little higher and only provided a 1yr warranty.