Lq4-Lq9 Question

[tonycillo]

i am looking to start my build and i am trying to find out what all has the lq4's and what has the lq9's

 

Silverado SS, Escalade-lq9

Silverado HD 2500, Yukon denali-lq4

 

is there anything i am missing?

[detjoe]

some vans had LQ4's

Vortec MAX had a LQ9

dont for get the 6.2's and the gen IV stuff...if I had to pick LQ9 or LS3

Edited November 3, 2010 by detjoe (see edit history)

[tonycillo]

some vans had LQ4's

Vortec MAX had a LQ9

dont for get the 6.2's and the gen IV stuff...if I had to pick LQ9 or LS3

 

 

ok sweet thanks.

 

what all had the ls3 in it?

 

reason dont care much about the lq4 lq9 is because i would use a 4 inch crank to make it a 404 new stock rods and lq9 pistons and not sure about top end work just yet

[Zebra]

IIRC the Silverado HD 1500 had LQ4 as well.

[PONYETR]

ok, im new to the whole truck thing, i kow all the LT and LS car motors (bought the truck for an everyday and had something bad ass to trailer my car. haha) so the LQ4 and LQ9 are both 6.0 motors? different compression ratios or? im a sponge and would love to soak up any knowledge someone would like to give out. and LS parts are interchangable with the LQ parts or heads close to the same? Thanks in advance!

[misterp]

so the LQ4 and LQ9 are both 6.0 motors?

Yes.

 

different compression ratios or?

Yes. The ONLY part difference between the LQ4 and LQ9 is the piston (LQ4's have dished pistons to run regular gas).

 

LS parts are interchangable with the LQ parts or heads close to the same?

For the most part, Yes.

 

Start with Wikipedia, there's a pretty good introduction on the LS-motors and the difference between the car series and the truck series.

 

Mr. P.

[chpspecial]

Early lq4 had weaker rods, 06+ had the same rods as the lq9

[BLUESS2003]

Hey i have a question for everyone, is there a way to tell them apart without tearing them apart?

[chpspecial]

Hey i have a question for everyone, is there a way to tell them apart without tearing them apart?

 

 

Only if you can get the vin from teh vehicle the motor came from.

[misterp]

The only other way (if you don't know the original vehicle the motor came from) is to pull all the spark plugs and do a good old-fashioned compression test and see what the pressure is on the gauge; this is a total WAG on my part but I would expect the LQ9 to build about 175-psi and the LQ4 to build about 150-ish psi, but I don't know the actual numbers. Several others have said they were able to bring #1 piston to TDC and pull the spark plug, and using a bent/hooked piece of stiff wire they were able to 'feel' the dish in the crown of the piston. I imagine that if you bring the piston to TDC of the exhaust stroke you could shine a flashlight into the exhaust port & illuminate the cylinder, then look into the spark-plug hole and see if you can find the lip present on the dished pistons. Sometimes you can get a clue from the accessories or flexplate installed, if the flexplate uses a spacer then it was installed with a 4L80 instead of a 4L60, and all 6-litres which were used with 4L80's are LQ4s from work vans or 2500-series trucks etc; if the power steering pump has an extra line for hydraboost brake system then likewise it came from a heavy-duty truck and is more likely a LQ4. But externally the LQ4 and LQ9 have no differences, their markings are identical. I know of a couple guys that got sold an LQ4 as an LQ9, you gotta really check carefully when buying a used motor.

 

Mr. P.

Edited November 8, 2010 by Mr. P. (see edit history)

[PONYETR]

Thanks a lot guys. its a good start to gain the knowledge. after 2 months of a car i bodyworked sitting in my driveway waiting to be paid off, he brought the cash today, so it looks like the headers and tune are coming very soon. I've been looking at Pacesetter stainless Long tubes, http://www.jegs.com/i/Pace+Setter/766/72C2265/10002/-1 and have noticed a majority or people have gone with Wheatley tunes. So thats my plan, any additional comments there? I've been considering a mostly mild cam too, any suggestions with good luck you've had? i'll check thru the rest of the forum too. thanks again guys.

[misterp]

Thanks a lot guys. its a good start to gain the knowledge. after 2 months of a car i bodyworked sitting in my driveway waiting to be paid off, he brought the cash today, so it looks like the headers and tune are coming very soon. I've been looking at Pacesetter stainless Long tubes, http://www.jegs.com/i/Pace+Setter/766/72C2265/10002/-1 and have noticed a majority or people have gone with Wheatley tunes. So thats my plan, any additional comments there? I've been considering a mostly mild cam too, any suggestions with good luck you've had? i'll check thru the rest of the forum too. thanks again guys.

Add transmission improvements to that list. To really get a significant improvement in daily-drivability save-up and get exhaust, CAI, and shift-kit parts and install at one time, THEN apply a the tune. The reason I say is that exhaust/CAI will not make a whole lot of difference *without* a re-tune. Likewise, upgrading your transmission internals requires a re-tune as part of that process. So best practice (to get you started) is to take a weekend and do the transmission, exhaust, CAI, and tune all at the same time. That way you only have to pay for a tune once; plus, the exhaust already has to partly come down to do the shift kit, so you may as well take it all down at the same time! Pacesetters are adequate, many guys make good power with those pipes and the cost is right, the fit isn't bad either, for a while it was all that we installed in our own project trucks; frankly IMO to get a better header you would have to pay $1300 for a premium set, the Pacesetters are the best "under $1000" set of headers on the market - my 2-cents. And since you live in Wichita with winter salt get the coated ones, because the raw Pacesetters will rust/rot on you like a bastard.

 

Mr. P.

[PONYETR]

again, thanks a lot man. everything helps. The truck does already have a GMPP CAI and 2 into 1 Magnaflow exhaust that the previous owner pu on with a single 3" turn down before the axle. Guess ill check into transmissin improvements too!

[Jordan836]

Thanks a lot guys. its a good start to gain the knowledge. after 2 months of a car i bodyworked sitting in my driveway waiting to be paid off, he brought the cash today, so it looks like the headers and tune are coming very soon. I've been looking at Pacesetter stainless Long tubes, http://www.jegs.com/...2C2265/10002/-1 and have noticed a majority or people have gone with Wheatley tunes. So thats my plan, any additional comments there? I've been considering a mostly mild cam too, any suggestions with good luck you've had? i'll check thru the rest of the forum too. thanks again guys.

 

 

Thats a little over priced for the pacesetters. Go to the Texas speed and performance website thats where got mine and I paid alot less shipped for mine. Also along with tranny mods your going to have to figure out what you want to do after the headers unless you connect it with your stock Y pipe. If not youll have to have a custom Y pipe made to connect to your cat back exhaust our fab up your own exhaust system.