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This customer came to us wanting to get a little more power out of his H2. The build started as just a tune, then to an intake and headers, to a cam swap, and ultimately a 2.3L Whipple blower.
This specific customer isn't interested in doing anything particular with the truck, just a fun toy that has all the power when he wants it.
We started with a set of Dynomax SuperMAXX long tube headers and Y-pipe and a JBA Evolcatback exhaust.
We converted the stock ECU to run a flex fuel sensor so the truck can run 93, E85 or any combination in between.
After that, we installed a Stage 2 Brian Tooley Racing Positive Displacement Supercharger cam kit which includes:
.660" Lift BTR Platinum Spring Kit
BTR Steel Retainers
Chromoly Pushrods
New Valve Seals
Some other supporting mods are:
Taylor Race-Fit 9mm FirePower Ignition Wire Set
DEI Titanium Protect-A-Boots
AC Delco BR7EF spark plugs
Walbro 450LPH Fuel Pump + install kit
Injector Dynamics High Impedance ID 1050x Injectors
Chevrolet Performance 3BAR MAP Sensor
Chevrolet Performance Flex Fuel Sensor
Strictly Performance custom heat exchanger
Doing some Base Line pulls to make sure the engine is ok and acquire hp numbers to compare to the final HP numbers.
These Chassis are huge! but we were still able to utilize the full time 4wd for dyno runs.
Bone stock engine bay...
Tearing the top end/front end apart for all the new goodies.
Got the Dynomax headers installed and the stock cam is about to come out.
We use wooden dowels to hold the lifters up while changing the cam out.
New cam from BTR next to the stock cam. The lobes are definitely bigger!
Some of the new parts going in from BTR.
In with the new cam!
New valve springs and retainers going together! Also installedChromoly push rods.
Installing the New Y-pipe and JBAcatback.
Dropped the fuel tank to install a Walbro 450 LPH Fuel pump.
Our tech was so fast, the Whipple was already on the engine before I could get install photos.
Belt is routed and the ID injectors have been installed into the fuel rails that come in the supercharger kit.
Air box is being fabricated and a temporary heat exchanger has been fitted. Even though these H2's are huge, there isnt any room in the front of them. We had to custom make a heat exchanger to fit between the radiator and A/C condensor.
Last edited by Strictly Performance; 12-21-2018 at 01:03 PM.
Another round of progress, we got the heat exchanger fabricated, and the air box and intake built and powdercoated.
The truck is currently on the dyno getting tuned, so we should have the final numbers and a video up soon...
We are very happy with how the air box turned out. Made out of aluminum, it is light weight, seals against the factory hole in the fender, and is easy to change the air filter.
Adding the finishing touches..
Although i don't Have a good picture of the ice tank at this time, we made one out of aluminum with an earls billet anodized cap. You can see it next to the coolant reservoir.
We wrinkle black'd out the throttle body as well to match everything else.
Our custom heat exchanger fits perfectly in the radiator and provides way more cooling area.
Comparison from the Heat Exchanger supplied with the Whipple kit.
Nestled snug between the radiator and A/C condenser.
Last edited by Strictly Performance; 12-13-2018 at 10:20 AM.
Reason: updates
Nice stuff so far! I eventually want to put FI on my 2003.
Couple of things I'd also consider. Strongly suggest to bypass the trans cooler built into the rad and add an aftermarket one in front instead. Not a good day when the internal barrier in the stock rad fails and coolant flows into the trans and ruins it. A forget which model but one of the True Cool ones fits near perfect in the front and is a pretty easy install.
On mine, I'm also going to be ditching the clutch fan and swapping in OEM HD dual electric fans from a truck. They bolt right in. You can find a few people here in the forums that also pull and sell the factory e-fans harness and relay setup with attaches directly to the under hood fuse box (you can also find a replacement OEM fusebox cover which has a second smaller lid to access the fans fuses and relays). Its a nice setup because it is 100% OEM components that bolt right in. Since you are going to be doing a custom tune anyways you just add the two control pins for the fans to the ECU and then enable them in the tune. EFI Live and HPT both have the efan settings in there for it and enable them just like factory so they cut in and out based on AC system pressure points, disable above 35 mph (you can set that as well), low/high speeds depending on temps, etc. The series parallel relay setup for efans is really nice. It does free up a nice little bit of power and eliminates the school bus roar in the mornings. It is a myth that all that power is freed though as the alternator will put a much heavier load when both fans kick on high. Nice to sit at a stoplight though and still have ice cold AC. One other with the fans - also need to upgrade the alternator to a higher output one to handle the additional load. Another big plus is you free up a LOT of space in front of the engine and take some stress off the water pump.
As arthursc2 mentioned, the trans is a very weak point. With the power you are putting into it combined with the rather extreme 6500+ lb weight of the H2 it will destroy the 4L65 in very short order if the owner drives it aggressively much. Everything I've read is that a 4L80 swap is pretty easily doable though and is one I'm going to be looking into on mine when the 4L65 craps out. I know the newer 6L80 can be done but is a pretty massive undertaking compared to the 4L80 which is the same generation as stock 4L65. That being said, if built right, the 4L65 can also be setup to take a quite a good bit of power as well.
12-10-2018, 10:27 AM
Hummer H2 2.3L Whipple Supercharger Cam Headers Build Thread!
One other with the fans - also need to upgrade the alternator to a higher output one to handle the additional load. Another big plus is you free up a LOT of space in front of the engine and take some stress off the water pump.