kris396ss

Hey guys, I am working on a twin turbo setup for my 396cid LT1.

I have a fully forged 396 (Eagle 4340 crank, H beam rods, 4 bolt straight mains, still looking at a piston to use for boost as it was N/A before)
Advanced Induction 200cc cyl heads and custom grind turbo cam
twin AGP BW S256 turbos/T3 housing with a .82 A/R that should support over 950whp
Aeromotive phantom flex 450 fuel system that I'll be using with pump 93octane gas, should support the power I wish to make but if not, a boost-a-pump will feed me up to the 950whp mark.

My goal with the LT1 was to make around 700rwhp on pump gas with methanol injection.

Originally, like 6 years ago, I decided to keep the LT1 because it would add too much cost to the project to go with a built LS motor and I wasn't sure about the long term reliability of pushing a junkyard LQ9 that far. Now I am starting to hear of guys making 900rwhp with just mildly worked LQ9 motors, but still most threads I find on the topic regarding how far you could push them reliably are many years old and don't have any follow ups after dyno #'s are posted.

I am wondering if it would be worth it for me to ditch the built LT1 for an LQ9? With the cost of the swap, I couldn't be building a LQ stroker or anything. I'd be looking at a motor I could do oil pan to intake for maybe 3k tops. What would I need to do to an LQ motor to make and support more power than my LT1 should reliably? Reliably is key here, if I wanted a time bomb I'd just throw more boost at my LT1. If a mildly worked LQ for the budget I can do won't be an upgrade over my LT1 then it won't be worth the swap.

What do you guys think?

69-chvl

iTrader: (11)

02 LQ9 here, 120k miles. Heads never off, head studs only, springs and Ls6 cam. Running 15-17psi with 11* on 93 octane for 2000 miles. A spritz of 50/50 meth injection too. So far so good.

yenkomike

iTrader: (2)

honestly . if you go ls turbo you will never go back to the old sbc platform.

I built a lq4 turbo and it was the best thing I did to my nova the power and street manors is second to none.

if you pick up a good engine take it apart clean it all up regap the rings and use a turbo cam and ls9 gaskets you will be good to go. we have done 2 engines in the last year like that and they are running on e85 14* timing and 15 # boost so far and they are holding up great. one is in my brothers Silverado and at 4300 lbs it runs very good no track times yet but it runs good .

mine has ben running for 3 years now but I'm only 10# boost pumpgas , it runs 10.50s at 130 mph at 3600 lbs with a 3000 ptc converter and a 3.23 gear. but I just swapped to e85 and cranked it up now that my axle can take it. new track times soon.

GMCtrk

iTrader: (23)

See sig. Stock lq9

kris396ss

Thanks everyone, it sounds like you are all making some good power, especially GMC with that E/T out of a 5000pound vehicle. I was hoping to see low 10's in my 4400 pound Impala SS and was thinking the LT1 could do it.


Everyone tells me the LQ is the way to go over the LT1 but I guess I am confused at exactly why. Not comparing stock to stock here, but a fully built LT1 with forged parts set up to handle power and a compression ratio set for boost. The only differences I can see are the following:

6 bolt mains on the LQ

better head flow on the LQ

better tuning capabilities for LS series motors

With my LT1, I'd be using a 24x conversions so the tuning really doesn't factor in. My AI heads flow just under 300cfm so I think I'd still outflow a set of stock LQ heads. If I could run a pair of L92 heads on the LQ motor though, I am sure that would be an improvement.

What do you guys think? My tuner, machinist and head porter all think I shouldn't have a problem with seeing 700rwhp out of my LT1 setup with methanol injection on pump gas. Can a mildly worked LQ for the budget of around $2500-3000 really out perform that and reliably?

Old Geezer

iTrader: (3)

" My tuner, machinist and head porter all think I shouldn't have a problem with seeing 700rwhp out of my LT1 setup with methanol injection on pump gas."

so, why not find out, then make a choice??

dburt86

iTrader: (2)

On my lq4 (with cut heads, so basically a lq9) I ran a 250 shot on pump gas for a year, then twin turbo'd the same motor and went 139mph on 12 lbs on pump gas

Cam only lq4, unknown mileage or background

sbcgenII

iTrader: (1)

Stock48 ran pretty decent with a sbe 6.0....

I had a built LT1 once. Parted it out. Damn that hurt the wallet.

kris396ss

For making 700rwhp, there really isn't too much to find out. I have seen first hand a few very similar setups make the same or more power, so I'm not too concerned about meeting that goal.


Bottom line though, I am almost positive the LT1 will make the 700rwhp mark I am looking for, and everything in my motor was built to handle that kind of power except maybe for the mains (straight instead of splayed).




If an LQ build within my budget can do MORE, and do it more reliably, then I might as well do it now while I can still sell a lot of my LT1 stuff as new. Not to mention I can save money on not buying some of the LT specific stuff like the 24x swap which I haven't purchased yet and the time I'd be spending welding up custom stainless turbo manifolds for my LT.

I'm at that tipping point where I'm just not convinced that a mostly stock/midly tweaked LQ that I can afford is a better choice than a fully built LT with good heads on it and forged parts. I know the LQ's are great motors, but I just don't want to go through the trouble of the swap if it isn't going to be a significant improvement in power and reliability over the built LT1.

It's kind of hard to get straight answers because so many are on the "LT's suck" bandwagon, but I have seen them first hand make some awesome power when things are done right. Obviously, if I could go back I would have sank my money into building an LQ motor up the way my 396 LT1 is built, but I can't afford to do that now so I'm torn between my built 396 LT and a cheap/mostly stock LQ.

Dburt, what's your cars weight approximately?

GMCtrk

iTrader: (23)

700 is an assload of power on the street. If you can reliably do it with the LT motor, I would just go that route.

forcd ind

iTrader: (7)

I don't know what kind of body your putting the engine in, but I would prob just stay with what you have, get the pistons, put it together, esp if it is setup for the body style you have
If you were starting from scratch, then ya, use an LS engine

30th t/a

iTrader: (51)

Does anyone know why it seems that you can push the Lq9s and Lq4s harder than the stock Ls1? What makes the Pistons and rings handle boost better?

69-chvl

iTrader: (11)

All LQ9's have the beefier rods, only some LQ4 have them. Not sure if the piston/rings are any better than LS1's.

Blown06

iTrader: (32)

Piston/ring seal is almost always better on an iron block vs. an aluminum block. Iron blocks don't flex like aluminum ones do.

JoeNova

My cam-only stock 5.3 made 700whp at 20 PSI on my old setup, spinning above 5000 RPM on the dyno. I've since then swapped intake/throttle body, rebuilt the hotside, and turned boost up to 24 PSI. Hoping to make at least ~820whp.

Reliability? I drive it every dry-weather day I have, even in the cold of winter. I'm sure you would be fine with an LQ9. Just make sure you get the 05+ engines with the floating pin rods. They're severely stronger.

oscs

iTrader: (19)

My question is do work out your legs? If you had it on a dolley or something with wheels I'd say you could push it a few miles before you got tired and gave up. Without wheels your best bet is dragging it.

Monte4ever

iTrader: (2)

Huh....lol.

tim wellington

i would go ls style engine .i am 47 years old .been in ls turbo world for about 4 years .i have had some bass *** old school engines 383/406/417/434 .the old school blocks wont hold up long at that power level .not saying it want make the power.just want live long. UNLESS IN AFTERMARKET BLOCK FORM.EXAMPLE MY buddy 406 gains 105 hp by switching blocks from stock to after market little m block .nothing else was changed .the block was flexing with studded 4 bolt caps. you didnt tell you bore x stroke combo .remember this you taking a block designed for 5.7 rod and adding 6 in or 6.125 with stroke on a 9.025 deck old school vs ls 9.240 deck designed for 6.098 rods from factory.Dont get me wrong i loved the old school .but no comparison to ls for strenght . PICK bought block up bare and felt difference

Jwooky

I notice in your sig you are from Oxford. Small world, mind if I asked who did your tuning? I am going to fire mine off soon and will need help.