Looking for input on a very hot subject!

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Hello all,

I actually joined this forum with the utmost excitement for my first mechanical post... the LSX forum! I am sure there are a lot of you out there with some seriously valuable input and real world experience on the coveted LSX into first generation F body.

I guess I should start by saying I actually had a motor for my car. Unfortunately, due to my recent move and the cost of freight... I did not see it as cost effective to transport the motor cross country. I sold it to a really nice guy putting it into a custom tubular frame rock crawler build, so hey... at least it's being used for a cool project. ;)

I had a 2008 LQ9 with low mileage I bought from a friend's friend. I chose this motor after hours upon hours of research as I still open, yet for the most part set on a twin turbo LS setup. From my time lurking here I have seen people rave about the iron block for it's handling of boost and ease of modifying. Also it seems to accept any head setup you'd throw at it. But here I am, back to square one and before I go out and get something similar again I figure why not ask some questions?

The car is a 68 Camaro Z clone and I'm doing a custom tribute car to both my lost uncle and a childhood dream. First and foremost I'm a boost freak. My last 4 vehicles have been boosted and in my opinion there's nothing quite like the kick in the pants feeling. Secondly... my uncle's car, in the late 80's, waxed more than one Ferrari in a straight line run and I'd like MY car to do the same thing. However, outrunning a 458 Italia on a highway (closed circuit, of course) isn't quite the same thing as it was for a custom built 350 to do to a Testarossa in 1988. So... yeah. ;)

Opinions? I'd like to leave 'budget' out of the equation for the mean time as I'm not focusing on that. If a $20,000 custom engine build is going to give me what I want and be reliable, then so be it. But being a technician by trade I've seen equivalents created for a fraction of the cost so I don't feel my end result will be that pricetag. And if it is, just don't tell my wife!

Go out and find an LQ9 again and continue with my original plan? The LSX 376 from GM is a sexy looking block, but I'd like to exceed 10lbs of boost on the higher setting (planning on a two stage controller) and I guess that would require the 15b, not the 8b. A lot of you out there seem to favor the 408? Was trying to keep the block size smaller, just for personal preference, but again... I'm very open to suggestions.

I guess my wants are around 600rwhp on a low boost setting, and somewhere above 900 if I decide I want to show off, lol.

[andrewb70]

So what's your questions exactly? LOL...

The LSX 376 15b certainly seems like a decent starting point. Give your power requirements I think they can be achieved with that long block. I wouldn't go with a stroker because of poor piston sealing issues at BDC.

Andrew

[Rod]

???? lot of words, to much for one post!

on the motor yes 600 is easy and reliable on a LS base

on the 68 Camaro Z clone start a build thread,,,with pictures..no pictures it never happened

on joining this forum......welcome

[option]

Probably should have waited until my very sick step son wasn't wanting me to color in Transformers while asking LS engine and boost questons... lol, my apologies.

Question 1 - Would you suggest an LQ9 as I already had for a reliable boost build? I could get another one for a lot less than say the LSX 376.

Question 2 - Are there any other factory LS engines that would be recommended for boost? My research always led me to the LQ 4/9 for both strength, cost and ease of finding. I'm very set on turbo setup, whether that ends up being single or twin. No blowers for this build. ;)

And yes! Pictures of my new toy to come, will round some up and start a build thread although there isn't a lot to put in there quite yet. Thanks for responding!

[andrewb70]

From what I have seen, most LS engines are boost friendly. There are plenty of junk yard 4.8, 5.3, and other engines running around on boost. The aluminum blocks don't seem to break but are more expensive. I guess the big question is, do you really want 900rwph? 600 is relatively simple...900 probably not so much or at least not "budget" friendly.

Andrew

[71RS/SS396]

Since you said to ignore the budget I would recommend the RHS aluminum block, it's 100 pounds lighter than the LQ block and has priority main oiling and will handle the boost levels required to get to 900 hp.

[carguykeith]

Lots of folks on LS1tech making 800whp on stock 6 liters, the rods are the weak link but the 07+ have an upgraded rod that is just barely good to that level. Basic recipe seems to be stock short block, LS3 topend with upgraded springs & 80lb injectors, LS9 cam & head gaskets with ebay head studs. Then truck manifolds with a v-band welded on, an S475 turbo, FMIC and meth injection. A (good) custom tune on the factory PCM should get you there for $8-10k.

Of course you still need another $10k in trans, converter/clutch, driveline and rear-end so $20k is a realistic budget

[option]

This is all some really good info guys... it doesn't seem to matter how many hours I read online, asking questions always teaches me something new. I don't need 900... I don't think anybody really needs 900 in a street car, lol. I'm throwing a high number out there as I would like a tame low boost setting, and a higher "i wanna scare myself" boost setting. The actual final numbers, honestly, are irrelevant to me. I just want a healthy, boosted LS block that I can both drive for the day down a back country road, and take to a race day if I choose. I have a lot of years of drag racing behind me, but I'm an amateur when it comes to Auto-X solo racing. Something I'd really like to get into, and I think it's a great way to meet like-minded enthusiasts.

If I do end up with a junk yard pull as my last LQ9 was, it is getting a complete overhaul and I will build it to last. Perhaps a more realistic approach would be a 600-750hp goal. That would be enough to put a Ferrari in the rearview, no? :)

[andrewb70]

This is all some really good info guys... it doesn't seem to matter how many hours I read online, asking questions always teaches me something new. I don't need 900... I don't think anybody really needs 900 in a street car, lol. I'm throwing a high number out there as I would like a tame low boost setting, and a higher "i wanna scare myself" boost setting. The actual final numbers, honestly, are irrelevant to me. I just want a healthy, boosted LS block that I can both drive for the day down a back country road, and take to a race day if I choose. I have a lot of years of drag racing behind me, but I'm an amateur when it comes to Auto-X solo racing. Something I'd really like to get into, and I think it's a great way to meet like-minded enthusiasts.

If I do end up with a junk yard pull as my last LQ9 was, it is getting a complete overhaul and I will build it to last. Perhaps a more realistic approach would be a 600-750hp goal. That would be enough to put a Ferrari in the rearview, no? :)

The more I learn about turbos, the more I realize that it isn't as simple as having an engine make xxxHP at xx boost and then making xxxmoreHP at xxmore boost. While racing engine that operate at high RPM can get away with that kind of logic, street engines that see a wide variety of driving conditions need to be more carefully tuned as to the size turbo that should be used. Most of the turbo engines I see being built tend to be more high end oriented. People want to brag about xxmore HP, but when I see the dyno sheet, the engines are fairly laggy in the midrange, where most of the driving tends to happen.

If you want to have some fun, try playing around the the Borg Warner turbo match bot application:

http://www.turbos.bwauto.com//aftermarket/matchbot/index.html

In the very last tab at the bottom, there are links to some youtube based tutorials that I found extremely educational, and eye opening. My next engine will have modest power but a torque curve that looks like a dining room table and it will idle at 650 RPM. That makes for a much more fun to drive as opposed to some sledge hammer engine that makes xxxmore HP at xxxhigh RPM...

Just food for thought.

[option]

Funny you should mention Borg Warner and the turbo matching application, Andrew.. lol. I'm fairly familiar with it as I have a fascination with EFR setups and was actually planning a turbo upgrade on my Cobalt SS/TC. That's before I finished some other mods and ended up putting down 317fwhp/383ft lbs with the stock turbo. The car became so violent to drive I figured it was best off left alone as FWD and huge torque aren't really the best of friends.

I've been playing with the idea the last few days about boring a 4.8 to 5.0 as I've come across a few articles focusing on short stroke, larger bore engines and the RPM that can be had from them. Does anybody have any thoughts on higher rpm, single turbo applications? I guess my theory would be that I could lug an engine around like that on a normal cruise, staying out of the power band and having a pretty tame toy. I think with the right head setup you could go from mild to wild by reaching those higher RPMs.

So many options... must be like women shopping for shoes. ;)

[71RS/SS396]

The more I learn about turbos, the more I realize that it isn't as simple as having an engine make xxxHP at xx boost and then making xxxmoreHP at xxmore boost. While racing engine that operate at high RPM can get away with that kind of logic, street engines that see a wide variety of driving conditions need to be more carefully tuned as to the size turbo that should be used. Most of the turbo engines I see being built tend to be more high end oriented. People want to brag about xxmore HP, but when I see the dyno sheet, the engines are fairly laggy in the midrange, where most of the driving tends to happen.

If you want to have some fun, try playing around the the Borg Warner turbo match bot application:

http://www.turbos.bwauto.com//aftermarket/matchbot/index.html

In the very last tab at the bottom, there are links to some youtube based tutorials that I found extremely educational, and eye opening. My next engine will have modest power but a torque curve that looks like a dining room table and it will idle at 650 RPM. That makes for a much more fun to drive as opposed to some sledge hammer engine that makes xxxmore HP at xxxhigh RPM...

Just food for thought.

One of the main reasons you see a lot of these turbo builds bringing the boost in at high rpms is it saves the engine, it's much easier on the bottom end of the engine to do it this way. We've all seen the magazine article about the stock junkyard 5.3/4.8 that made 1,000 hp with e bay turbos but if you look at the dyno sheets and boost curve they didn't bring the boost in until 5,000 rpm which is why it lived.

[option]

One of the main reasons you see a lot of these turbo builds bringing the boost in at high rpms is it saves the engine, it's much easier on the bottom end of the engine to do it this way. We've all seen the magazine article about the stock junkyard 5.3/4.8 that made 1,000 hp with e bay turbos but if you look at the dyno sheets and boost curve they didn't bring the boost in until 5,000 rpm which is why it lived.

Yeah I remember reading that article for the first time. I've worked for a number of shops at this point in my career and most of the pooched engines I've seen have come from abuse/high RPM. It's true... RPM kills motors. But, as you said, bringing on that power at a higher RPM allows the motor to 'live longer', for lack of a better term.

I'm not going to attempt to break any records, or win any awards, just weighing out my options. So many avenues! I'm still new to the board and I've been reading for at least an hour or two each day... are there any members here that have a 4.8 setup? Perhaps even boosted? I found the type of setup I'm looking for on another forum, but was swapped into a foxbody 'Stang, in which the owner claimed the stock bottom end had over 100 hours of rev limiter abuse on it. Was almost hard to believe, lol.

[andrewb70]

One of the main reasons you see a lot of these turbo builds bringing the boost in at high rpms is it saves the engine, it's much easier on the bottom end of the engine to do it this way. We've all seen the magazine article about the stock junkyard 5.3/4.8 that made 1,000 hp with e bay turbos but if you look at the dyno sheets and boost curve they didn't bring the boost in until 5,000 rpm which is why it lived.

Tim,

Please help me to understand this better. Is it the high cylinder pressure that can occur at high boost at lower RPM that kills parts? I always thought that high RPM killed parts faster than anything else?

Andrew

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Tim,

Please help me to understand this better. Is it the high cylinder pressure that can occur at high boost at lower RPM that kills parts? I always thought that high RPM killed parts faster than anything else?

Andrew

Fairly obvious that high RPM puts a centrifugal strain on parts such as the crank, cam and in turn the heads. At least this is what I've learned in all my technical training courses. However, I've read that because the compression of air (turbo, blower) increases temperatures dramatically that it becomes a heat issue. You'd think an intercooler would take care of this, but that would only be in a rolling state... you gotta wonder what kind of strain a motor gets while being stalled up and creating boost before it launches. I'm not an engine builder per-say, or a machinist, maybe someone who is would chime in. :)

[71RS/SS396]

Tim,

Please help me to understand this better. Is it the high cylinder pressure that can occur at high boost at lower RPM that kills parts? I always thought that high RPM killed parts faster than anything else?

Andrew

The high rpms keeps the low speed TQ from getting very high, that saves the rods and head gaskets a bunch. HP math is TQ X RPM divided by 5252, so the higher above the 5252 number you are the less TQ is required for a given HP.

So if one component can only handle X amount of TQ you need RPM to add power.

[andrewb70]

The high rpms keeps the low speed TQ from getting very high, that saves the rods and head gaskets a bunch. HP math is TQ X RPM divided by 5252, so the higher above the 5252 number you are the less TQ is required for a given HP.

So if one component can only handle X amount of TQ you need RPM to add power.

So what you're saying is that if I wanted a low RPM torque monster engine I would need to build a very stout short block?

Andrew

[71RS/SS396]

Yep, ever seen the crank and rods in a diesel? When you bring in the boost at low rpm it basically tries to push the crank and rods out of the bottom of the block.

[option]

The compression that drives a diesel motor is on a completely different scale than that of a gas engine though, but I see what you're saying.

Tim; do you feel with the right setup that a boosted, high RPM motor could actually provide a fun weekend cruiser as well as a track warrior come Saturday? I can play with gearing if I feel the car to be gutless from one stop light to the next. I'm just not finding any info on my own anywhere that is deterring me from this crazy notion, haha.