h3 engine swap thoughts!

[Kyle]

okay after doing some research i found that 99-07 gm cars that had the 5.3l mainly used the 4l60e transmission. soooo what cars would be a good donor car i could buy and swap everything out of, ecu, pcm , bcm etc? any thoughts? my goal is to be the first person to have done a driveway engine swap on there H3! Its doable and will take some effort! But im game!

 

[High Five H2]

as far as I know, just about every GM v8 uses the same bellhousing pattern. I bet just about any gen 4 engine would swap in. same engine mounts, everything. i'd go with an L92, personally, but I think using the 6l80 tranny is half of the benefit.

edit - if you used a larger gen 4 engine, they all use a different tranny, so there would be some re-wiring to get them to talk. kind of a pain, but not impossible. take a step back and use an LQ9, or whatever gen 3 engine you want, then you'd have to use a different reluctor ring. one gen uses 58x, the other uses 24x (right? it's 3 am and my memory is fuzzy). either way, more fooling around with wiring.

personally, if you're looking to keep the same tranny, i'm sure you could find a stroker kit or something. use an aluminum block to save weight (or to make up for your bumper and rack and whatnot). i believe the L33 is aluminum... don't remember though.

i'd like to do the same project, but use a 6 speed auto instead.

 

[Chook]

Here is a 6.2 L V8 Swap putting out 450Hp. Took a fair bit of work to get the electrics to talk to each other and a custom loom had to be made. http://www.woofpacracing.com/Projec...H3Hummer/tabid/63/language/en-US/Default.aspx

 

[Expendable]

unless you have someone who can turn a blind eye when smogging you're going to need an 06 or newer engine at the minimum to be CA refereed.

in which case I don't think that will work unless you use your factory PCM but I could easily be wrong since I don't know how the OBD only smog checks work.

 

[Kyle]

unless you have someone who can turn a blind eye when smogging you're going to need an 06 or newer engine at the minimum to be CA refereed.

in which case I don't think that will work unless you use your factory PCM but I could easily be wrong since I don't know how the OBD only smog checks work.

glad you brought that up, i wonder if theres away to mod the pcm to output clean smog so i could just show up, the guy plugs it in, it says good to go, yet i have another engine.

 

[4speedfunk]

I have a neighbor down the street that has (2) brand new Laguna Seca Mustangs. These are factory race cars and they come with a roll cage, no back seat, spoilers, exhaust cutouts, etc. They also come with a "street" key and "track" key. Depending on which key you use to start the car...it can be a grocery-getter with emissions, or a ferocious beast ready for the SCCA circuit. So, I'm thinking you might be able to tweek parameters for a sniff test...then return it to "ozone-hole" mode afterwards. Hell, Ford seems to be able to do it.

 

[06 H3]

My main concern is the 4l60e but raptor claims they have a upgraded trans to handle a ton more hp then the stocker. I'd love a 4l80e swap but it seems difficult. The raptor kit should handle the power you throw at it

In all reality I think the biggest issue with H3 trans is heat.

 

[06 H3]

I would also just go by the book and get it done within specs of smog then modify it. That way if you ever move to another state you have proof and papers that it was a legal swap in CA. Which should make it legal anywhere seeing how strict ca is

 

[H32NV]

I'm starting to look into this too. It looks like on GMPartsDirect, I can get a 5.3L crate motor for around $4k. I'd love to do the swap from my I5 to the V8. Anyone have any other input? I'd probably keep the tranny, do a t-case saver, and the motor at the same time. I'm also running a Ron Davis radiator with an integrated trans cooler. Should have to swap the ECM, motor, and maybe some stuff under the hood like air intake etc. Is there really anything else?

 

[spillKill]

if u swap for the v8 could u keep the 5speed or would u have to go to an auto?

 

[SolidusJ]

if u swap for the v8 could u keep the 5speed or would u have to go to an auto?

Go Auto, the 5speed can't handle the V8.

 

[Chook]

Yep go Auto. In Australia the Tow weight limit was halved for the 5 sp manual over the 4 sp auto. I originally ordered a manual adventure H3 but I had to go auto as I tow 2000Kgs regularly (Boat & Camper)

 

[skeptic]

May I ask, why do an engine swap instead of trading up to an Alpha? I can't imagine saving a ton of money when all is said and done, plus all the labor and potential headaches, and the Alpha will be newer and likely have fewer miles. Is it the challenge you are after? Sentimental reasons to keep your 3?

 

[H32NV]

May I ask, why do an engine swap instead of trading up to an Alpha? I can't imagine saving a ton of money when all is said and done, plus all the labor and potential headaches, and the Alpha will be newer and likely have fewer miles. Is it the challenge you are after? Sentimental reasons to keep your 3?

I have a lot invested into the 3, including some custom suspension work that might negatively affect the re-sale value to a dealer for trade-in on an Alpha. I welded on low-profile rear spring hangers and re-arc'd the springs, and did bilstein 5100's on all corners, and a shackle lift in the rear. I also put in a CI front diff, which I know the alpha comes with, but I wont get paid-out for by a dealer on trade-in.

On surface level, I thought that economically id be best to do the v8 swap myself. The long-block kit is roughly $4k on gmpartsdirect, and i could sell my old I5 motor. Possibly pay for a new PCM, and then have a little project with the wiring harness. I have the auto, so it should bolt right up, in theory. I think the biggest pain will be the wiring...

autotrader offered me 9k for it. what a laugh. KBB says $15k. still seems a bit low. Alphas are going for $25k as far as i can tell on ebay. I think swapping to the V8, I would be in the game less than $10 grand and have a brand new motor.

thoughts?

 

[06 H3]

I'm with you 100% and you have an 06-07 alpha how many are there of those? Lol not to mention sentimental value is very high on mine.

You and I have a lot invested. Time and money...so why start over? It's in my plans. If you want to get real crazy look at the 4bt swap on a diesel forum I posted a few weeks ago. Someone is doing it....same trans modified oem harness same axles etc. I'm all for an engine swap and not starting over with an alpha. I just need some more time and money...I will get there and it will probably be cheaper vs swapping out rigs.

 

[skeptic]

I have a lot invested into the 3, including some custom suspension work that might negatively affect the re-sale value to a dealer for trade-in on an Alpha. I welded on low-profile rear spring hangers and re-arc'd the springs, and did bilstein 5100's on all corners, and a shackle lift in the rear. I also put in a CI front diff, which I know the alpha comes with, but I wont get paid-out for by a dealer on trade-in.

On surface level, I thought that economically id be best to do the v8 swap myself. The long-block kit is roughly $4k on gmpartsdirect, and i could sell my old I5 motor. Possibly pay for a new PCM, and then have a little project with the wiring harness. I have the auto, so it should bolt right up, in theory. I think the biggest pain will be the wiring...

autotrader offered me 9k for it. what a laugh. KBB says $15k. still seems a bit low. Alphas are going for $25k as far as i can tell on ebay. I think swapping to the V8, I would be in the game less than $10 grand and have a brand new motor.

thoughts?

Couple thoughts - unless it's a simple bolt-in affair, they always take longer and cost more than you expect. Also, I thought there were some issues with the firewall or something and it wasn't until '08+ that you could even fit a V8 in without significant re-work. I don't claim to know anything about this, just passing on what I remember reading as something to check into before going fully committed.

With what you have invested in your truck already, it just might make more sense to do the V8 swap.

 

[cgalpha08]

I do remember something about the firewall being thinned or pushed back for the alphas.

Sent from my DROID BIONIC using Tapatalk 2

 

[06 H3]

Yea that is true but there have been 6.0 conversions in 06s so a 5.3 should fit

 

[Kyle]

yea i plan on keeping my h3 forever, i have way to many good and bad memories with that car that its staying with me till it or i go. so i dont mind the not making any money back on it. i just think it would be a fun DIY project to do a swap since the i-5 is really getting on my nerves as far as power. ive done wiring on many other cars so im fine with all that, its just the custom mounts and stuff i will need help with.

 

[skeptic]

... the i-5 is really getting on my nerves as far as power.

I've been wishy-washy about trying to find an Alpha to replace my I5 H3T, leaning heavily toward finding an Alpha in recent months. This weekend some friends wanted to show me a new camping and 4-wheeling spot (for actual 4-wheelers) so the 4 of us piled into my T and went for a drive. Up and down steep mountain roads, 315/75/16 Duratracs, 4 adults... Ya, I had to slow down to keep the cruise control from holding 5k RPMs, and even then it was a struggle. Part of the conversation along the way was about renting or buying 4 wheelers, they finally understand why I keep saying I don't want to tow anything that big up into the mountains. We have rented 4-wheelers in the past, but only at a "cabin" where we didn't have to tow them.

I do not have a PCM4Less tune, and that's the one alternative to trading in on an Alpha that I've been considering. Honestly though, with the possibility of towing stuff up twisty UT mountain roads, I just don't think a PCM tune is going to cut it. If I could swap a V8 into my truck for less than the price difference in trading it in on an Alpha I'd consider it. I'm just afraid the shop would come back with lots of little surprises and the end cost would skyrocket. No way would I do something like that myself, I gave up wrenching long ago because I hate it so much.

 

[06 H3]

Any custom work will require bugs to be worked out. Loaded down my I5 is a dog! I need more power... I'd do it myself and work out the bugs but it will take some time to get it reliable. That's my thing, reliability.

 

[Kyle]

has anyone provided feedback with a pcm tune? predator makes a pcm tune and it adds 40hp. lets say you had an 06 that comes with 220hp+the 40hp+airdocs with cold air intake 5-10hp= about 265hp if we play it low. thats not that far from the 300hp of an alpha. And say you had the 3.7 at 240hp now your a 285. thats even closer. i want someone with a pcm tune or predator tune to chime in and see if they say they can really "feel" the extra gain.

 

[High Five H2]

I have always wondered how feasible swapping the I6 for the I5 would be. it's probably not enough of a gain to justify the costs... but it's an interesting idea.

 

[Expendable]

has anyone provided feedback with a pcm tune? predator makes a pcm tune and it adds 40hp. lets say you had an 06 that comes with 220hp+the 40hp+airdocs with cold air intake 5-10hp= about 265hp if we play it low. thats not that far from the 300hp of an alpha. And say you had the 3.7 at 240hp now your a 285. thats even closer. i want someone with a pcm tune or predator tune to chime in and see if they say they can really "feel" the extra gain.

Our H3 Raptorq ECM Upgrade offers your 3.5L, 3.7L and 5.3L Hummer an additional 40HP, on average​

http://shop.predatorinc.com/raptorqperformancecomputer.aspx

claimed is not the same as actual. and it's most likely at the flywheel not at the wheels.

Also peak power is not what you want. you want a nice strong low end torque curve. that's where an engine swap would really count. If I had an H3 and was going to swap in an engine I would go with a 6.0 Vortec Max at the very least if not the 6.2L used in the 08-09 H2s.

 

[Kyle]

ahh matt beat me to the link, but yea the gm hp ratings are at the flywheel too, not rwhp. and thats why i want someone with a tune to chime in and see if they can really tell that big of a difference