Hey all i could use some input from all you LSX guru's out there. Im thinking going the LQ4/LQ9 route or LY6 and buying a heads and cam package from these guys.
http://texas-speed.com/p-1170-precis...m-package.aspx
My budget is around 4k and i figure its cheaper than finding a L92 which still cost a pretty penny for a complete one. This is going in a purpose built car stripped down to bare bones so i really dont care about street driving manners at all. 6.0 seem to be going for 1k or less from what i found and that cam in the package is as big as you can go before cutting the pistons.

 

is 4k your budget for just the engine or for the entire swap?

you are on the right track running a 6.0l with those heads, you still need to check ptvc with any cam swap when the lifts get higher.

what are your goals for the car?

 

My 4k budget is for the motor. They said thats the biggest cam you can run without PTVC issues i figured it should be plenty for awhile. Trying to put the money to best use. Iron 6.0's seem pretty plentiful and i would love to go the aluminum route but aluminum 6.0s and 6.2s are still up there in price. Figured money would be better spent on a good top end. My goal for the car is roadrace/autocross purpose built car something like Bigmods here on the forum. If i want comfortable my GMC Sierra keeps me plenty comfortable driving around town. This car is purely for fun.

 

Look into coil overs.
Also, adjustable shocks are nice. QA1s, or (my choice) Vikings (they have struts on the way...could be before the end of the year).
UMI, BMR... and others for the under carriage stuff....
Engines are icing on the cake... handling is where the right/left stuff starts.
Enjoy.

 

I would suggest NOT doing coilovers. They have a lot of great benefits for reducing weight on the front of the car and are GREAT for drag cars. But for a car that gets tossed into corners they dont really fit.

The traditional struts available for these cars (read: Koni yellows) are EXCELLENT, coilovers dont provide any real performance gains over quality factory suspension setups beyond weight savings.

Coilovers put all the cornering loads onto the strut tower which was never intended to see those kinds of loads. There are reinforcement plates and whatnot, but I would imagine that even with those and a strut tower brace there is still going to be significantly more body flex than with the spring going into the k-member. The factory K-member is SOLID. Even if you switch to an aftermarket tubular k-member, many of those are dubious for high cornering loads. One of the aftermarket companies makes a "road race" k-member that has a LOT of extra reinforcing gussets and braces on it. VEry nice piece, but when you do all that you lose most of the weight savings. Coilovers, aftermarket k-members, and the coilover a-arms can cut a LOT of weight on a drag car that doesnt see those kinds of loads, however.

The adjustability component to coilovers is very nice, but they make weight jacks for our cars too, which gives you all those benefits of coilovers without sacrificing handling.

And probably the WORST effect of coilovers on our cars is that they significantly limit inboard tire width. Our cars like having equal tread patches all the way around for proper balance. Probably because our weight distribution is more towards the front than the corvettes that often have 17x9 and 17x11 or other similar staggered tire setups. With a traditional front suspension setup you can go as wide as 17x11 in the fronts, I think one guy here even has 17x12's, and iwth 18's you may be able to go wider. 17's interfere with the balljoint so you can actually WIDER inboard of the hub with 18's. The realistic limit for a stock setup is 17x9.5 in the front only because 17's hit the balljoint. With 18's you can go much wider than that, but not with coilovers. The spring/strut combo are trying to occupy the same space that the extra tire width going inboard of the car is. That doesn't matter on a drag car, but for a track car or autocross car, the tradeoffs in potential tread patch size can be HUGE, and severely negate any performance gains that can be had from switching to such a setup. That combined with how good Koni's are and it just really doesnt make sense for that application.

The rear shock mounts are nowhere near strong enough to support the weight loads of the car. They break even with factory shocks mounted on them. But thats another issue for another day. There's a lot of reasons NOT to go coilover on these cars. The benefits just arent there.

You should register at frrax and see what they're doing. Check out BIG_MODS 's car, he's got a whole build thread over there and made custom weight jacks into his factory k-member, pretty trick stuff. He does a lot of really neat stuff to his car that is worth noting. He also built the car for wheel to wheel competitive racing, so some of the stuff he does may be overkill for you (like the cage).

BIG_MODS' car:


And here's a really good build thread of a guy who's racing his thirdgen in CMC:
https://www.thirdgen.org/forums/memb...road-race.html

 

I stand corrected.
BTW- I was not thinking of rear coil overs.... easy enough to see there is no structure for them.
Tire patch argument easy to follow.
Not sure I buy the factory K is better view.
Big Mods has some car!

 

THE reason for coilovers is you get a much higher wheel rate for a much lower spring rate, so you have your cake and eat it too. You lose about 1/2" of inside clearance for your wheels and tires, but either you're doing coilovers for ride quality with <275s, or you're going widebody for >315s anyway.

 

Yup already have all the suspension stuff taken care of minus GC weight jacks which im saving up for and still need to have my cage welded in. Im in the process of stripping out the interior for the cage. Thx for the heads up Infernal. Im sticking with the stock suspension geometry for sure.

 

The factory k-member is engineered with a massive safety margin. The aftermarket ones may be well-designed, but none of these companies have the resources and tools and man hours at their disposal that GM's R&D has.

The main thing that turned me off of tubular suspension components is the scenario that happened to redraif. She had a tubular a-arm broke. A long thread and research and intelligent arguments later, and you start to appreciate why the factory used ugly flexible stamped A-arms. They wont break on pot holes. Those tubular A-arms are a lot better idea with coil overs, than with the factory geometry. That's why most of the tubular a-arms with spring perches on them are so massively braced and reinforced, because the amount of stress potholes and high load cornering put on it is INSANE. The ride quality argument for coilovers is also why fourthgens use a SLA suspension instead of a mcpherson strut setup (dont fear, BMW and Porsche have used mcpherson strut setups in many, many high performance cars). When you put the spring at the end of the a-arm, you dont have to weld perches to the tubes, and the springrate doesnt have to be nearly as high because it has more leverage. But our springs being so far inboard of the ball joint have to be VERY strong, and they put tremendous loads onto tubular a-arms. All those same loads then go into tubular k-members, and those have even more welds and gussets and braces than the a-arms do, and some of them offer "road race" k-members that look significantly more beefy than the regular ones do from any of them, so even they acknowledge that in exchange for incresed stiffness and marginally decreased weight, you lose strength and durability. Thats somewhat alarming to me.

Look at the drop spindle situation. They are by far the best solution for a lowered car because they preserve the stock suspension geometry which is GOOD. They ALSO limit the size of your contact patch and can lead to all sorts of problems if you get a flat tire, but they preserve stock geometry and performance through the range of suspension motion.

https://www.thirdgen.org/forums/susp...e-failure.html

I just get nervous with fabricated suspension pieces. I use tubular rear end pieces because they're relatively simple and see more straightforward loads. A rear LCA will see mostly just tension and compression forces. There are so many other linkages that spread and distribute lateral forces, and the geometry involved doesnt require elaborate pieces either. But in the front, with all the weight the car holds up there and all the loads these cars see in everyday driving or aggressive/competitive driving, they make me nervous. Something as integral to the safety and structure of the car as a k-member, I will stick with heavy, reinforced factory parts that are designed to NEVER fail before I go to aftermarket fabricated parts. The. factory k-member's only drawback is that it's heavy, but it's also low in the car. I dont think some of the stronger aftermarket k-member options are much lighter than the factory one, but they might be.

Add to that what we've learned from the redraif situation:

https://www.thirdgen.org/forums/susp...arm-broke.html

1. Tubular parts are stiff but because they dont flex they are prone to failure during shock loads unless heavily triangulated.

2. Welds are easy to do improperly that will result in decreased strength because of heat treating issues. It is impossible to know as an end user if each weld is sufficiently strong and done properly to maintain the strength of the metal it is welded to.

3. These aftermarket companies tend to overbuild instead of over-engineer. They are enthusiasts and car people, but they do often lack engineering backgrounds and proper training to draw from during the design phase. They just build something they think will be strong enough.

4. Aftermarket companies do not warranty their parts. They repeatedly stipulate their parts are for "off-road use only" AND stipulate that they are not designed for "competitive" use. This is to make sure you cant sue them for part failures after they cause you monetary or medical damages.

They build parts that look good, parts that they dont think will break (Because they have consciences, they dont want customers to get killed or hurt, they want repeat business), and then they make sure they're not liable so that when a failure happens it doesnt bankrupt their business.

I dont think there's an intentional selling of shoddy parts, and I think most of what is available is actually done very, very, very well. But tubular parts, for all their advantages, have issues. For a drag car that gets trailers and doesnt see high cornering loads, tubular front suspension pieces make a lot of sense. For a track car, a heavily reinforced tubular front suspension setup makes a lot of sense because tracks are usually very smooth, and as long as there are no weak welds they shouldn't break because there wont be any shock loads (read: pot holes, curbs, armadillos). I'd still check all the welds for cracks regularly just because. For a car that has a turbo and needs the extra clearance a factory k-member cannot provide, that makes sense too. I would still be tempted to use factory a-arms, though.

But for a dual purpose streetcar/track car that will be driven on the road with your friends and family in it... I'm not sure I'd want tubular front suspension pieces. To each his own, the parts are strong and look nice, but you have to understand the factory parts were built to last and they were built to withstand incredible loads. They may flex a little more, but that's the cost of durability.

A lot of this same stuff applies to aftermarket wheels too. Not recommended for street or competitive use, yet marketed that way. Not given any kind of serious engineering analysis, and sold for massive money:

http://jalopnik.com/5953859/this-guy...is-blaming-him

A factory GM wheel would never have broken on street tires provided it wasnt already damaged from a previous incident. A factory GM wheel would probably not break even if it ALREADY had serious damage. They're designed to outlast the car. Be careful people. Im not saying only use thirdgen wheels, but I am saying if you can, it's safer to stick with something GM has done it's own engineering analysis on. If you dont want to do that, at least pick a brand that has a SOLID competitive track record or one that is JWL or TUV approved. A JWL wheel is going to be safe (your factory wheels are JWL stamped).

The point is, there is a place for OEM stuff. OEM stuff isnt going to get you killed.

 

So just to make sure i got this right

Pull out 6.0 LQ series
Max lift cam for LQ short block cam(trying to avoid cutting the pistons)
L92 heads tailored to support the cam
L76 intake?(not sure if i can use the LS3, getting conflicting info)
= make lots of power?

Im new to all this LS stuff but i just want to make sure i got everything right before i start ordering parts. My plan is to take a pullout 6.0 and buy the best heads cam package i can get without any PTVC issues using L92 heads and maybe this cam 277LR HR-113 from Comp. The intake will be handled with a L76 or maybe LS3. Maybe headers from Hawks or the ones from ebay along with having the EFI tuned. How far can i spin this 6.0? 7k possible? What sort of power can i look at making with this set up? Or should i stick with a 317 head since it will give me more valve clearance? I know its not always about lift but im just trying to find the best bang for the buck combo.

 

You want the cam tailored to the L92 heads, not the other way around.

You can use either the L76 or LS3 intake with L92 heads. The difference is the way the MAP sensor mounts. Which MAP sensor you use depends upon what control system (PCM) you use. I'm using L92 heads with LS3 intake and 2003 LQ4 PCM. I used the LQ4/L76 MAP sensor, because it it compatible with the LQ4 PCM. However, I had to get "creative" mounting the LQ4 MAP on the LS3 intake.

 

Ahh ok good to know. I hadnt thought about that issue. Thanks for the heads up. I will most likely be in the same situation if i go that route with the LS3 intake. Been spending alot of time on LS1tech digging through info and taking notes. So much to take in.

 

so... would 245's still fit with coilovers?