Turbo Mike

So I ran across a low miles LS6 for cheap money so I grabbed it.
Motor is clean and complete. I want to crank it up a bit and put it in the GTO.
I'm pretty noobish to the LS world but I've been doing some asking/homework.

My goals:
Highest rpm possible without immediate failures.
Reasonable drivability (drive 150 miles a day min for work)
Reasonable mileage (same reason)
Max N/A power on pump gas.

Current plan:
Kooks 1 7/8 longtubes (bought already)
No cats
3 inch custom exhaust, dual, with dynomax ultraflow X pipe and dynomax VT mufflers
LSX 102 intake and tb
102 mm maf housing with 2010 camaro maf
Texas speed MS3
Dual valve springs (reccomendations??)
Twin disc clutch (spec probably?)
42# ford injectors (have already)
HP tuners (have already)
Double roller adjustable timing chain (maybe retard the cam a little?)
Ktech rod bolts
Shim the oil pressure relief

Straighten me out if I have any fail ideas here, but going for 7500 rpm and 475hp, torque doesnt really concern me as much as a fat high powerband.

Thanks for reading.

PREDATOR-Z

That kind of rpm is worthless with such a cam. Shift it in the right spot, not just 7500 for the hell of it.

Turbo Mike

Then what cam do I need? This is why I asked, dont have a cam yet.
I'd love it to rev to 8k but I know thats not reasonable with a streetable hydraulic/pushrod valve train.

kinglt-1

iTrader: (26)

Your not going to get any longevity out of the stock bottom end reving it over 7k. You need quality forged rotating assembly, top of the line valvetrain, and a solid roller for those rpm's.

zacht

iTrader: (18)

why the "i want to rev to 7500 rpm???"

sounds more like a cool factor or something. its out of the power band of most cams for these cars and its not needed to spin these motors that high anyway.

once a month theres a thread on here regarding "i want to build a ...ls... and spin to 8 k....makes no sense to me.


all in all plan looks good. i think 475 will be hard on stock 243's. and i think the fast 102 isnt needed. i vote drop the 102 idea. thats 1300 bucks. and keep the stock ls6 intake and invest that money in heads....

then get a custom spec'd cam for your setup. i think it will put you closer to your goal.

also, me personally, i like a cam that's advanced just to get into the powerband quicker. these are heavy cars. in my mind....torque beats horsepower any day.

zman1

Maybe this is a stupid question, but why bother swapping an otherwise stock LS6 shortblock (unless you are forging it) into the GTO? I take it you currently have an LS1 GTO? Pull the 243 heads off that LS6, have them ported and polished, pick out a nice cam, and throw it into your LS1. Hold on to the LS6 block you have for a future forged build or sell it. With the LS6 intake manifold already on your GTO, and some 243 heads you will basically already have your LS6 for all intents and purposes.

redtan

iTrader: (5)

This ain't gonna happen, you want N/A power with a big donkey dick cam for 7500rpm but you also want mgps? That thing is going to be getting less than 20 on the highway if that.

You do a boosted engine and get the same power with better mpgs than stock.

Turbo Mike

I'm swapping to the LS6 block because it already has better breathing, lower miles, slightly better crank and pistons, more compression, better oiling(especially for higher rpm)and its together. I'll sell the complete LS1 later.

I understand that its not going to get 30 mpg and that pump gas isnt going to make 600 whp. I'm ok with 15mpg, I just dont want single digits.

That being said, I'm sure theres a high rpm streetable combo that can be had with a LS6.

If 7000 is the max reasonable rpm I can do, then ok, 7 grand it is. It doesnt HAVE to rev to the moon, thats just my preferred driving style. With IRS and gay rear diff, torque isnt the answer for anything that I do with the car.

Thanks for the replies so far, I'm here to learn.

hardcore4sure

iTrader: (1)

The GTO LS1 already has the LS6 block, crank, pistons, etc and intake, you just need the heads and wallah you have and LS6. Get the heads ported, get a cam and put them on your current motor. Keep the LS6 block and build it up later for when you pop the original, which you will do if your spinning 7500rpms. Just FYI most LSX intakes aren't tuned for 7500 rpm, they're made to produce power/torque under 7000 rpm. You will need a custom intake to spin that high and still make power.

Turbo Mike

Mathematically the piston speed seems more than acceptable at 7500 rpm, is it really that big of a deal spinning past 7k with a LS1?? What is going to come apart? Should I just fix that now? Theres nothing wrong with my current motor at all besides not being fast enough lol

zman1

Exactly my point, yes it's a pretty big deal turning an LS1 to 7500. On an otherwise NA LS1 reving to 7k without doing rod bolts is a touch risky. Not to mention you're going to be making your peak horsepower numbers somewhere in the neighborhood of 5 - 6k RPM, you would be better of shifting to get back into your strong power band.

hardcore4sure

iTrader: (1)

On the stock bottom end lets see. Rod bolts won't hold, pistons aren't forged so heat will be an issue with them, rings probably won't hold unless upgraded, valve springs, valves would need a serious upgrade including titanium where ever possible , rocker arms would need to be upgraded to something like Jesel very pricey and girdle, internal bearings would need attention, may need to go to dry sump oil system. You would also need to strengthen the main caps, maybe titanium rods . I'm mean just off the top of the head those are some of the issues that would need to be addressed for 7500 rpms and reliability. If you want to approach NASCAR revs you need NASCAR $$$$. Light car go for HP, heavy car and a week rear end strong Midrange TQ and HP up to 7000 is what you need. Just food for thought.

zman1

The other idea is to sell or trade your LS6 for a LQ4/9. Sure, the iron blocks weigh a little more, but going that route will give you a 4" bore to play with. Then you can still sell your LS1 short block and use all of your existing accessories.

zman1

Are you recommending that he buy a bike or S2000?

Fry_

with a cam that will pull past 7k you wont start making power till 5k it's going to be a slow boring trip to 5,000rpm in an street car that weighs close to 2 tons. plus your car will have horable drivability and be a general pain in the *** to drive. you have 16 valves and 1 cam not 32 valves and 4 cams 7,500rpm is just stupid, you'll just break parts and loose races.

'02TA

Couldn't have said it better myself

Turbo Mike

This is why I dont get it I guess




This is my subaru, I built the motor and tuned it.

100mm bore, 75mm stroke.
Stock crank.
Stock block.
Eagle H beam rods, wiseco pistons.
Stock heads
Stock valves
Single springs with titanium retainers
130# injectors, 86mm turbo


It has been HELD above 9k for literally hours and hours with no issues. I drift it. Nothing balanced, no dampener on the crank at all.

This is why I'm puzzled that 7500 is a lot lol. Smaller bore, larger stroke, but still not a long stroke by my considerations. I know its far from apples to apples, I get that, but I'm quite familiar with building, tuning, and operation. Just looking for LS specific tips and parts to use. I'm not planning on drifting or seriously racing the gto, but once its sideways I want something to work with thats all.

This I'm ok with. Thats why I got the model that lets me pick which gear I'm in and when to dis-engage the motor from the tranny :-) Subaru doesnt get full boost till 6400.

This I'm not ok with.... but my definition of horrible driving and pain in the *** is pretty loose compared to most people

Fry_

well with a reasonable cam you could get the gto sideways at 2500-3000rpm that gives you 3-4k to work with I would think that would be plenty.

zman1

On a boosted car with the appropriate sized blower you may continue to build power as long as your blower is efficient up to 9k. Engines with displacement dont need to rev to the sky to make power. With a smaller engine and a lighter rotating mass physics is on your side a little more. Now if your LS was FI I could under why you would want to rev to 7500k, but then the how and how much come into play.

kinglt-1

iTrader: (26)

Bottom line 7k rpm is max with the parts you posted. If you want a high rpm setup, you will need: FORGED BOTTOM END, SHAFT MOUNT ROCKERS W/ SUPPORTING VALVETRAIN, SOLID ROLLER CAMSHAFT, CARB STYLE INTAKE( Super Vic). Plastic intakes lop off air flow above 6800rpm. You can try running the stock bottom end, but its not going to survive those rpms for very long. Thats why most people go with a big cube, lower rpm, lots pwr/tq under the curve setup. it's more reliable, streetable, and overall more fun to drive because power under the curve is what makes a fast street car!