SPANKY LS1

iTrader: (24)

Especially with the the Eagle 4" cranks coming out for cheap, one could build a forged 383 out of a LS1 aluminum block, thereby adding ~40 cubic inches while adding no weight. As I understand it, strokers are known for their low-end torque compared to an all-bore motor. My thought and questions are this: Todays "big" head and cam packages (such as mine) have the reputation as being high powered but "peaky". What would a 383 do with a good set of heads and a big cam (244/250 or something like that)? I mean, combine what makes a "big" H/C package successful in producing 450+ rwhp, then add 40 cubic inches, and I see no reason why a 460hp/410tq H/C setup couldn't become a 500hp/470tq 383 H/C setup, right? Or is it not that simple? Where would a 383 with a 244/250 112/114 peak, and would the long stroke somehow hinder its ability to spin to 7,000 (even though all internals are forged)? I guess what I'm asking is, would a 383 stroker (not all-bore) be a good way to add a TON of tq to a peaky H/C setup?

Thanks, Shawn

H82BBad

no final figures yet on mine. I cause I need larger injectors.

So far I am making about 90 more ft lbs of torque and 30 more rwhp but I can only run it to 5500 right now.

Mine is lunati crank,oliver rods,236/240 cam,lunati pistons and TEA heads

SPANKY LS1

iTrader: (24)

See, that is the quandary that I am in, I want to do forged rods and pistons, and for ~$800 I can get an Eagle 4" crank locally. If you're numbers are 90tq/30hp over your previous H/C combo, that is a signifigant increase for $800 (the difference in a forged 346 with a stock crank, and a forged 383 with a forged crank). Kind of seems like a no-brainer then. Was it still pulling away from your H/C graph at 5500, was there any indication that it was "running out of steam" as it is generally accepted that strokers sometimes do?

What size injectors do you have, and what size are you going with?

Thanks, Shawn

gator's 99TA

iTrader: (2)

it was teh cost of the cranks and the tremendous power the all bore motors were making for similar costs. if you want to spray it or dont want to rev it to the moon, no doubt stroker is great. BUT the extreme over-square condition make for motors that dont make the rwhp big bore motors that make great peak and hold it for a long time = fast car make. also stock cranks have proven to hold 700 rwhp.

H82BBad

so far it has made 90 more ft lbs peak to peak and 30 more hp peak to peak compared to my 11.31 combo.
Now it is no where near peak power on the stroker yet, I am adding fms 30 lb injectors (36@ our fuel pressure)
I am currently running the stockers.

as far as it running out of steam I have not seen that yet. Maybe when I add the injectors. I do plan on adding and lsx intake as soon as they arrive.

SPANKY LS1

iTrader: (24)

My point is this, though:

Assume a 450/410 H/C car peaking at ~6600, add 40 cubic inches bringing the power/tq to 500/480 with a bigger cam, also peaking at ~6600, the 383 would kill the 346, both NA and on spray, wouldn't it?

An all bore isn't in the budget, I have the $$$ to do rods and pistons, so is the extra ~40 cubic inches worth the ~$800? I would think if you could gain 50 rwhp and 70 tq, it would be well worth it, no?

Thanks, Shawn

gator's 99TA

iTrader: (2)

area under the curve. with all the lame talk about dyno, that is all it is. lame. the strokers i have seen with good heads and healthy cam have made great power down low in teh rpm band (under 4K rpms). if you are worried about peak, then strokers will do you nothing. the gain in peak hp isnt worth a stroker crank.

SPANKY LS1

iTrader: (24)

Ok, I think we're both saying the same thing. I know that most of my gains will be below my peak HP, but will I lose PEAK HP or PEAK TQ? Is there any situation where I would LOSE power/TQ/ability to spin the motor to 7k? Will I be trading high RPM power for low end TQ, or with a big enough cam, still make good power at 6000+?

gator's 99TA

iTrader: (2)

no i dont see ever LOOSING power with adding stroke given the tune is correct and every other variable is constant.

2001 Pewter WS6

iTrader: (43)

We will see what kind of numbers we can get out of it. I have a Lunati 383 Stroker with a set of Absolute Speed heads and a 236/240 Comp Cam. I am going to get it dyno tuned at Vette Doctors on Saturday. The car is running so rich that it is actually setting a code. It ran a 10.98@121.81 that way. There is definately a lot more left in her. The torque with an A4, 3.73's and a 4400 converter in rediculous. It totally blisters the tires at will on the street.

H82BBad

I dropped down on converter when I added the 383
will be nice to see the differences between our set ups when dialed in. since are cam specs are so close

Beast96Z

iTrader: (21)

You will be able to run a more aggresive cam because cubic inches will eat up camshaft. I would bump up to a X-4 or X-5 and spend the $800 on the crank. You'r under curve will be awesome!

maddboost

iTrader: (11)

Spanky LS1 you have a PM

95Snoozer

with the 383 stroke I think your torque would be even higher than you estimated

Keith

Think about it. BBC engines with a 4.00" stroke can rev to 7k rpm if built correctly. They do have a larger bore granted. But these LS1 heads flow incredible numbers. It can rev if you get the right cam, I would do a 383 stroker and gain all of that extra torque and some more hp to boot.

z98

Using desktop dyno, even a 5 inch stroke didn't cost any peak horsepower on an LS1, but it did put it much lower in the powerband.

With a 4" stroke, it gained 3 hp and about 45 ft/lbs over the stock stroke.

With a 5" stroke, it only made the same stock hp, but torque jumped to 473 @ 3500 RPM, more than 100 ft/lbs more than stock.

Also, the HP peak was a mere 4000 RPM.

So even when taken to unrealistic extremes, it doesn't look like a stroker will cost you any peak hp.

Might want to check the piston speed numbers on that before spinning it to 7000 though

From just what I've done here, it looks like a longer stroke will make a car peak earlier. This goes along with conventional wisdom which says a short stroke can rev easier/longer than a long stroke.

Adding more air to the engine looks like it would also extend the torque line quite a bit. That 477 LS1 (5" stroke) is starving for air with stock heads. A 3" stroke (286 ci) made almost the same horsepower (about 15 less) as the 477 and was still making 200 ft/lbs at 7500 rpm.

Spanky, if you (or anyone else) wants to give me the flow numbers for a set of heads, I can run some back-to-back comparisons of a various bore/stroke combinations and post up the results.

gator's 99TA

iTrader: (2)

desktop dyno has proven to not work well at all with teh ls1. parasitic loss with longer strokes (drag on teh side of the walls) is true, but at these power levels and stroke limited to 4.0" and under 7000 rpms, it is barely a factor if at all. the very weird intake runner length and peaky power are oddities as are the flow characteristics of the heads cant be accounted for with a generic program. it is very good with SBC/BBC etc it is though.

z98

So far, its been within 10 hp of being right on for every combination I've put into it, on all types of motors, from a turbo'd 4 cyc probe to SBC to LS1's.

Of course, it gives FWHP with no accessories, and that isn't what most people dyno their car at, but it is great at giving you a general idea of what a particular modification will change, compared to what you had done last.

383ss

iTrader: (14)

I need to post a graph of my 473 rwhp 383 stroker vs a 463 rwhp 10.9X sec 346 H/C car. it's a HUGE difference in area under the curve.

11 Bravo

iTrader: (3)

I think a 383 stroker is a great street racing motor. That is probably what I should have bought, but I had the money so what the hell.