I'm thinking of building an ls2 with a LR4 crank for a Ls1 swap car...
If I want to save some money I will go with a 6.0 truck block.

I have more faith in a stock Ls1 crank (esp 3.27 stroke) than most ppl and I have not seen any aftermarket cranks in short strokes anyway.

If a 2.0 4g63 (~3.46 stroke) can make about 1000hp on a knife edged stock crank why cant a LR4 nodular...

I'm looking to blend street manners, MPG, Economical build and power.

Probably the truck block... Tougher? Anyway

4.0" bore 3.27" stroke. Closer to 329cu

The main question is the rod selection.. So far all I have seen in the length I need are eagle H beams.

6.3" 4340 forged rods L19 bolts. If you guys with strokers run 6" rods with 4" long strokes I know I can go with even longer rods .... But that is expensive and the rod ratio at 6.3 or stock LR4 is awesome as it is.

Forged pistons with offset wrist pins.. Probably wiseco.. 35psi+ N20 at 9k rpm could'nt kill them on a 4g63... Good tuning is part of it...

Oversize ARP head studs. O-ring head and block. Yep N20 motor......

LQ9 heads. Cam and valve train? I want to wind it out and ample exhaust flow to allow big hits of N20.

Progressive n20 with a second bank of injectors fueling for better atomization... Dual channel wide band o2 with EMS operating in closed loop at all times monitoring EGT's as well as the wbo2.... This is the best way to make big power with n20 safely...

I have some other ideas like running 85% ethanol which is so cheap here I have ran it on a turbo four so dont go because I know all about the stoichemetric afr difference etc... I just have'nt built an LSx engine..

 

Do you mean 347? A 327 CID engine from a 3.905" bore is de-stroked.

 

I said 4" bore and 3.27" crank.....

It comes out to a bit above 327 cu/in.

Its the crank from the 4.8 truck gen III in the 6.0 gen III block, 6.0 Gen III heads and a weiand LS1 aluminum intake since it makes adding the extra injectors and n20 easier.

 

I see what your after. Looking for a bigger bore and shorter stroke.
My oponion would be to build a 4.030 bore and a 3.622 stroke.
You still have a great bore to stroke ratio and will make some killer power plus get 370 cubic inches.

 

Also unless your going for a low compression build your theory sucks. You will need a 61.5cc head just to get back to 10:1
And with the LQ9 heads your planing on running your looking at 9:1. Not a good Nitrous Motor at all.

(That is with flat tops and a .054 gasket)

Even with a +6 piston, heads milled .030 and a .040 gasket your still only at 10.5:1 and probally having P/V clearence issues with a big cam. All in all not a good setup IMO.

 

Sounds interesting. I am using a 6.125 rod with a 4.075 stroke on an iron 6.0L. I don't see why a 6.3 rod wouldn't work well. The problem I see is that the intake won't work well at that high an rpm. You may want to look into one of the carb intakes with an elbow and 90mm tb, or the FAST 90mm intake and 90mm tb. Sounds like you want max power out of it so spend the extra money on the induction for better results. Your also going to need a solid cam to spin that high. Good luck and post how it works out for you.

 

Now if he goes solid roller and uses a nice set of 54cc heads we could have a sweet setup.
54cc heads, flat tops with a .040 gasket for 11.6:1 and some serious RPM's.
Your ganna need solid roller heads to turn those RPM's.

 

Who said anything about flat tops...

They will be DOMED pistons.... I need a higher CR to run the ethanol even when I'm not spraying... Probably 14:1 compression ratio. If I was'nt spraying I'd run even more (16:1).

The right pistons will put CR where I want it and the ALL of the charge in the combustion chamber not the piston crown...



The stroke is in part to increase rpm but also to increase fuel economy.

If I do a RX7 I will probably paint a CF hood to match the car, install racing seats and run lexan everywhere but the front... Basic sterio... etc A really light car.

If I do the A4 quattro brutal low end tq is the last thing AWD needs.... I have cut 1.7 or so 60' on a stock dsm driveline which looks like doo doo compaired to a audi. I still dont want loads of low end tq... It will still Launch harder than anybody who is'nt tubbed can and once moving a quick reving engine will keep pulling. Its also a better match for the audis existing gear ratios as its original engines have a peak power at a higher rpm..

As for the intake I know it cant be a polymer. A sheet metal intake is another option... The weiand can be ported, welded 2nd injector bungs, and drilled and tapped for n20.

 

Thats gonna be a funny looking piston with the LQ9 head being used. 14:1 and lets say you took the LQ9 head WAY down to 62cc's.
Thats a +20cc piston with a small .040 gasket.
Good luck. Take some pics and lets of see could be a real neat setup.

 

Use a 5.3L or milled ls6 head to get less of a dome. The carb intake is metal and will flow better than the ligenfelter one. Even with porting you would still be stuck with the 78mm tb. Big restriction for making lots of power. Not trying be negative but trying to help you make the power. I've done three intakes on mine and getting ready to swap again soon.

 

I agree on the intakes.
I was only going by the fact he said he was using Lq9 heads.
A 54cc LS6 head would be the best bet.
Then a +12cc piston would work for 14:1
Another piece of advice is take the 6.0 block and bore it out. This wont hurt RPM's will give you more cubes, will help the heads flow better, and add a little compression.
How about a 4.030 bore and 3.27 stroke.
Now a 333 cubic inch motor and that +12 cc piston gives you 14.2 compression.
Maybe a 4.060 bore if you sonic test the 6.0 block.
338 cubes and 14.35 compression.
The heads will flow better on this bore as well which is always good for power.
Just wondering what kind of cam are you considering?
Gonna put it on a higher LSA to spin to 9000RPM's?

 

You don't want to bore with a big shot of nitrous. Better to keep the thicker walls.

 

True so stay 4.030.
Many of us have sprayed a hell of a lot with that combo and even your old 4.040 combo would work well.
Thanks for pointing that out stroked, 4.030 should be fine.

 

This sounds a great idea especially for a 4WD or lighter car.
i am considering something similar for the future but probably 7.5:1 CR and twin turbos (well boosted). No emissions probs and plenty of high end power.
How high an RPM is practical with the 2 valve heads? i guess dropping the stroke further for higher RPM depends on what else can take it.

 

sounds like a lot of 60's and 70's type engine theories. something I haven't had the money to do to an Lsx motor yet. I hadn't thought of running that high of compression, but it should run well.

 

If it is a fresh block I'll run 4.0 if it needs to be cleaned up 4.030 max

Well I have seen 14.2cc+ domes for SBC's

The Lq9 head was just an idea to save money and still get the better port design...

I'll see..

FAST LSX
http://www.popularhotrodding.com/tech/phr_0309_fast/

Ok now I agree.. I'll just have to put the secondary injector above the N20 bung and aim it at the same target as the primaries. Maybe epoxy in some bungs after asking FAST what type to use...

As for cams I will have to play with EAPro using data from of the shelf grinds...

Probably 114 or so LSA with split duration....

With the reduced stroke and longer rods the short block is going to breath differently than the mills most people are caming here. I will need to make my decison based on what the science says a 327 wants and not 6.0liter plus results.. The pistons are inhaling and exhaling at different velocities than the long stroke engines.. The high CR and longer tdc dwell time will help with the exhaust stroke too...

Chevy made a 360hp 327 in 1962 and a 375hp FI 327 in 1964... All on Dino Iron heads with 2.02 1.60 valves.

Factor in the LS1's inherently better head design, pro-porting, aluminum, bigger valves, roller cam.. too many differences to type plus alcohol fuel and you will see that despite being a 327 I may be giving many strokers a tail light view... Any gueses w/o the silly gas?

I might just build and dyno tune the engine and find a car to put it in later... I'm getting dreamers and lowballers on the GSX plus the work beater is acting goofy.. I might just keep it put the 1680cc injectors back in it and retune again for E85. I'll eventually have an AWD turbo 4 car burning fuel that costs less than regular and a RWD v8 in a RX7 or on the high end a GTM kit...

 

Oversquare engines are'nt 60-70's theories. Um formula 1. Sure at the RPMs we drive on the street most strokers are fine but with the same amount of hp targeted between two engines the shorter stroke will stay fresh and will run longer. I will also get better MPG.

The LR4 crank is cheap because nobody wants it.

The compression is due to alcohol fuel and a bit lower than id run if there were no N20 plans...

Nitrous engine building
http://www.hotrod.com/techarticles/42580/index.html

And 2005 GM genIII trucks are being built for E85.. I will probably run E85 on the primary and E98 on the secondaries

 

Ok back on task... what I wanted to pin down...

RODS..

Cheapest I'd consider eagle ESP 6.3" $625
Most expensive Oliver Billet std weight 6.5" $1300

No comparison.....

 

run the longest rod you can. like you stated, the longer the rod the longer the dwell times at the swing of tdc and bdc. for some reason 3:1 sticks in my mind as optimun rod ratio.

 

No its not 3:1 for every engine...

It depends on if it is a drag track strip only.. 1.5 is fine... A road racing car... 2 ish or a circle track car turning high rpm all day up to 3:1....

Honestly if the oliver 6.3" rod was less than their 6.5" I'd buy them but they cost the same so I'm going longer.