Building my LQ4 engine in my Denali XL

[Ridculous]

Well like the title says I am in the process of building a engine for my Denali XL due to oil starvation to the top portion of my motor, failure to 4 CAM bearings, damage to my CAM, damage to my lifters and valve springs and #8 cylinder....the engine only had 128k but I have been towing my 7000lbs travel trailer from Tulsa, OK to the Rocky Mountains 2x a year in the summer time. It stinks but when life gives you lemons make lemonade ...so I have my local GMC dealer break the entire engine apart and had them ship it out to the local race / engine builder in town. So they are currently checking the block, heads and other engine parts to see if they can be reused. This is the only dealer that I have ever encountered that is willing to put on and even recommend aftermarket parts and engines and install them!

The outcome I am looking for in the denali XL version 2.0 is
1) Durability to at least 100k before a rebuild
2) Torque down low to tow my trailer in the mountains and get this pig off the line (want a nice flat power band from 1500 - 5000)
3) Keep my piss poor fuel mileage at or close to 9-10 MPG in the city and 14-16 on the highway (7-8 towing)
4) Power goals at the crank figure 525+ hp and 500+ lbs


So far I've talked to a couple of builders and tuners and thinking either

Option 1 - N/A engine stroked to 408 - 416 CI with a nice small CAM and ported heads and new forged internals including crank

Option 2 - FI engine stroked to 408 CI with all forged internals, blower CAM with a Magnacharger 2300 sitting on top

I will be building the stock transmission as well to hold the extra power.

Also this is our family car and my wife and nanny drives this as well so can't be to crazy (loud)... I'll post more information later this week after I speak with the machine shop!

Budget for the build is between $10-$18k

Let me know your thoughts!

 

[Mister H12]

I vote Supercharged lemonade

 

[FreshLikeOprah]

You can make 525 crank HP without needing FI. Stock crank, rods (since yours is a 05) and go .030 over with some Diamond forged pistons. Flat tops. A set of 317 or 243 heads, with a nice port job. Full bolt ons, and a cam in the mid 220s duration. You'll have nice torque, make over 400hp at the tire and be reliable. Probably do a 07+ Intake with a LS3 Throttle Body. You'll need a Link X control box to run it. As for your trans, a 4L80e is really a better option. Esp being in a big heavy XL. A stock 80e with just a shift kit will be all you need. And maybe a tight 2500-2800 converter.

 

[YukonXL04]

If your going to be towing in the rocky mountain area at high elevations, then definitely go with FI.

 

[Ridculous]

Thanks guys for the input. Priced out a Magnacharger with the upgraded 2300 (Radix blower) shipped for $6400....

I'll update the post as I get more information!

---------- Post added at 01:27 PM ---------- Previous post was at 01:18 PM ----------

Also what type of headers should work on the 408 cubic inch

 

[FreshLikeOprah]

Definitely go with 1 7/8s. America Racing headers and Kooks are the best you can buy. Texas speed makes some nice long tubes also. But go for the 1 7/8th whatever you buy.

Was just trying to save you some coin. That's why I was saying you don't need to go all out if you only want mid 500s HP.

 

[Ridculous]

Thanks boss great suggestions on the headers. Question is will the N/A have that 500-550 lbs of torque between 1500-4500 that I need. Having 500+ hp is nice but need the torque to pull.

 

[YukonXL04]

Yeah it should being a stroker motor... However it won't pull near as good at high elevation as a forced induction motor. And I'm all for NA, but not when your at higher elevations, especially when towing something heavy...

 

[Front Street]

Excited to see what you decide on. I'm pricing my engine build on my 04' Denali right now. Don't have the budget for a supercharger, so I'm going more the route you are on the N/A option. Kooks headers are the #1 recommendation and like others said, 1 7/8 are what have been recommended to me almost 99% of the time. I'm going for similar HP #'s, but reliability and more efficient power are my goals. So far, it's a Lunati Cam, Trick Flow heads and great internals, the only thing to really decide on is the intake and TB. Drive by wire is what I think I should stay with, but haven't asked the engine builders about that yet.

What are you thinking for an intake and TB? Guys love FAST, but some have said the gains aren't worth the $1000.00.

 

[josueh95]

ever thought about a torque converter and a tru cool 40k tranny cooler? thatl get you in your torque curve alot easier