theastronaut

Thanks for that link! It's funny how they're advertising them as "new" when they are used carbs. Those are obviously rebuilt, you can see the oxidation marks on the bottom flanges. I've bought those for as little as 300 each before; I was going to use two of those on my stroker VW engine until I decided to turbo it. I've got two already, so I'd only need two more. Like that ad states, the venturis are removable and different sizes are available to tune for the airflow you'll need. There is a idle circuit and main curcuit, and emulsion tubes that are used to tune when the carb switches from one to the other so you can tune for both optimum cruising and WOT AFR, and also use the emulsion tubes to change how soon/late the transition from idle to main happens. Neat carbs, the Italians sure know how to build 'em! I'd actually really rather use 48mm Dellorto DRLA carbs as they have a far superior idle circuit but I think the bore spacing is going to be too close on those to match the port spacing. The IDA's only have two progression holes but can be drilled for more to increase their idle circuit metering ability, where the Dellorto's come with five.



I spent a good bit of time searching the forum this morning to see what it takes to run over 8000 rpm, and like you guys have been saying I found that there's so much you've got to do to go over ~7500. I was assuming that a more modern LS engine would be much easier to make it rev higher. Heck, the valvetrain in my stroker VW would go to 8000 and higher with just a spring change using caveman-simple and very affordable parts that are the typical and easy upgrades over stock. I guess that's what I get for assuming...


So now that reality is setting in, I guess 7500+ is out of the picture. With the slower piston speed of a 4.8 crank, could stock rods with ARP bolts hold up at 7500 rpm? Or would LS1 forged pistons weigh more and put more stress on the rods?

Exidous

iTrader: (11)

On a destroked motor and better rod bolts you should be fine to 7500. But for 500 you can get a good h-beam set fo rods so you might as well.
Again the valve setup will get you. A solid roller setup would be best. You will need to set aside 500 for solid lifters, 500 for adjustable rockers and 300+ for good springs. I'd also look into hollow valves. A lower lift and 1.8 ratio rockers may help with instability. Titanium in the valve retainers and locks.

BigRich954RR

iTrader: (1)

OK If your really want to build a high rev LSX I love the idea. What your looking to spend on it really ? What do you really want it to DO ?

If your trying to do it cheap with cheap parts. Then listen to all the people that never build a High reving LSX.

If you willing to put money out let me know ill go into details. and push you the right way to build it.

Also you keep trying to stay carb really bad idea for max hp and good MPG bite the bullet once and go FI

for 7500 rpms most stock parts will work just dont ever over rev or it will cost alot

theastronaut

Thanks, I'd appreciate any input you're willing to share! I'd like around 400 hp, 7500 max with a rev limiter to keep from going over. I don't mind spending what it takes to make it do that reliably, though I may not be able to do it all at once- I'm building the truck from the ground up so I'm spending a ton already, but I don't have a deadline on it so I'm saving up and getting what I want instead of rushing it, cheaping out, and ending up with a truck I'm not happy with. I do want to atleast build the short block once and have it in the truck for good, and upgrade the top end later if I need to go that route. Either way, it will eventually be done so I need a solid build plan. I'm about to pay off a loan, and that will free up an extra 400/month to throw at it.

As I poster before, I can tune Weber or Dellorto carbs to get max power and good mileage; my VW with dellorto's lean cruises at 16.5-17 AFR and goes to 12.5-12.7 AFR at WOT with a smooth transition inbetween. It drves as smooth as the LS2 in our Trailblazer SS with worlds better throttle response. MSD has a LS ignition controller with a MAP input for added advanced at low loads for better mileage and better stability for lean cruise carb jetting. My VW gets 36.25 hwy mpg so carbs can get good mileage. AFR is AFR whether youre carbed or EFI. Carbs usually make more max hp since they better atomize fuel at WOT. I don't want to spend 4k+ on a individual throttle body intake, then have to pay someone to tune it when I can do the same thing with carbs for less than $1500 and I can tune it myself. I already have two 48mm Weber IDA carbs so I'd only have to buy two more, or I can sell those for around $1000-1200 and buy new repro's with improved idle circuit progression ports. I can buy four repro's for what the original Webers are worth, so that would be my best bet.

I am going with carbs on an IR intake, no need trying to talk me out of it. If it fails miserably I'll post and let y'all know, and then convert to EFI.

L33 5.3, LS1 bore and 4.8 crank. ~312 CI
Stock rods, ARP bolts if that'll work. (slower piston speed and higher rod ratio)
Forged rods if needed.
Forged pistons.
Solid roller lifters, adjustable rockers.
Double roller timing chain w/damper.
L33/799 head castings, C5 Z06 hollow valves. Send off for CNC porting?
Self built IR intake, four two barrel weber/dellorto carbs.
Hooker cast iron headers, I want the retro look- its going in a '66 C10
MSD ignition controller.
Drop in trap door/baffled windbags tray.
Possible fabricated/weld on wings on sump for higher oil capacity.

zippy

I see that what you're going for isn't the performance, it's just to have something different so that when you're talking about it around other guys you sound smarter than you really are. As said you can build a motor to go faster than what you're looking to do with way less trouble out of a stock LS6 or LS3. The idea of the destroke is cool for conversation, but running 8000rpm doesn't need a destroke it just needs a crapload of money put into a valvetrain. The idea of using Gen I small block rods also is just pointless when there will be no gain in running them over a Gen III/IV rod in an application like this. If you're going to waste your time on carbs, use an SV1 or at least 850cfm Pro-Systems. With your goal changed to 7500rpm you can just buy a stock 5.3L L33, port the heads, change to lighter valves, better valve springs, Fast 102, and big enough cam to get you there. A stock 5.3L with the newer rods should have no problem with 7500rpm, just the valvetrain. I would also recomend a better oil pump though simply due to the rpm such as the Melling 10295 or 10296.

DONAIMIAN

iTrader: (18)

The cast iron manifolds will be the single most counter productive part on the motor. Spinning that kind of RPM the motor will NEED a long tube.

As for the solid roller stuff, I'm telling you this from experience. Get the block machined to run a .904 lifter or bigger, I regretted not doing this. Don't waste your time with any of the stud mounted rockers, go for true shaft mounts meaning jesel or t&d. Get the rockers set up on the heads before you instal them on the block, and get the pushrod holes opened up to accept a larger 3/8in version.

4WardInv

Zippy, I kinda like this topic of small cubes but had some more questions, since I'm new to the whole LS world too. Forget about the carbs or trying to spin 8000 rpm for a minute! Wouldn't the idea of boring out a 4.8 or even a 5.3 to an LS1 bore size be a good idea just so you could put a better head on it and unshroud the valves? or are the smaller heads really good enough all ready in you're opinion?

SSCamaro99_3

iTrader: (1)

Why bore 4.8 and 5.3 blocks to LS1 size, when you can find LS1 blocks for sale all over the place. If I were building an NA engine, I wouldn't even look at any option under the 4.00 bore LS2/6.0 (depending on your material preference). So many more head options. If I were building an engine today (on limited funds), and needed to use a stock block it would be LS2 or 3 with a 4 inch stroke.

mark21742

Just for your info on rpms, I spin my 408 to 8,000 rpms with just forged crank, h-beam rods, forged pistons and melling 10296 high volume oil pump....the bottom end isn't that complicated, then after that all you need is heads that flow enough to make that rpm possible, lifters and springs that can keep the valves under control and not floating everywhere.

I am also running the Edelbrock proflo xt on my GTO and love it....I wonder if you want to stay carb if you could get someone to machine out a 90 mm+ side draft to bolt on the front of the proflo

theastronaut

It is for the performance, but I'm not equating more HP to performance in this case like you guys seem to keep doing. I want to move the HP peak up (where it peaks) while maintaining a reasonable amount of low end torque and driveability. That's what the IR intake is for, not just so I can run carbs. I'd run IR/ITB EFI but I don't see the point in spending 4k plus when I can build an IR intake myself to use $1200 buck carbs with the same performance. Destroking the engine will give a higher rod ratio, and slow the piston speed down to a point where I shouldn't need forged rods/crank. As said before, less displacement should get better mileage as well, and I'm not looking to make as much horsepower as possible- this will be a daily driver. I'm almost finished with the long block for a turbo stoker engine to push my VW well into the 11's and it's gunna be a heck of alot more fun to outrun people in a "slow" VW than it would be in my truck. So, I don't need two quick street cars. Like I said, I'd be happy with mid 13's or slighly quicker. A stock 5.3 with bolt ons can make around 400 hp, that's enough for me. But, I want the wider/smoother powerband that a short stroke/high rpm engine with an IR intake has since I'll be doing autocross/open track days. As said, I'm not looking for it to be competitive, just to get it out on a track and have fun. The way the engine is built will change the performance, whether or not it makes any more horsepower than a typical build.




Thanks for the reply, larger pushrods and lifter diameter are great ideas. Do you think shaft mount rockers are needed with 7500 rpm max? Or will a light valvetrain reduce the need for those? The lighter the valvetrain parts are, the less spring pressure is needed too...



The heads on an L33 are part of the reason I wanted an L33, they're the same style casting as a LS6. I'm not looking to make a ton of power, so I think they'll be sufficent as they are, or maybe with minimal porting. Smaller cubes= less air flow for a given RPM, or in my case the same air flow but at a higher rpm, moving the powerband up. The IR intake will restore bottom end torque and driveability.



Because I can buy a complete running L33 for around $800, that is also an aluminum block, and comes with head castings identical to LS6 heads. I'm not looking to make all-out HP on this build. If I was I'd go 6.0.


Thanks for the reply. What valvetrain parts are you running, and how is it holding up at 8000 rpm? I'm only going with carbs so I can use an IR intake; I don't want a plenum style intake.

DONAIMIAN

iTrader: (18)

I run 220 on the seat and 550 open and my valves are 98/89g. My valvetrain is good for way more RPM than it'll ever see as long as I'm on a plastic intake. That being said I went with a Comp stud mount steel rocker... snapped it in half. I'm on jesels now and never looking back. The lighter weight valvetrain is nice and all, but I would compare cost of hollow stem valves with the spring selection. The spring that I wanted to run was stout enough that I didn't have to worry about it. PSI 1513ML I believe is the number. Fits in the stock spring pocket, but you're limited on the lift.

mark21742

Ls7 style comp lifters (can't remember part number off the top of my head), ls2 lifters trays, comp .650" dual valve springs, stock rocker with the bearing upgrade...all together pretty simple setup, but it works great....just couldn't keep a4 trannies behind it lol

zippy

The idea that you have of making a smoother and wider power band with a short stroke motor is just ridiculous. You don't need a short stroke either to run the rpm. The stock crank and rods from an L33 as an example since it is the motor being discussed will easily take 7500rpm. I also agree that a larger bore will allow for a better cylinder head, but the newer head designs are so far advanced that a head such as a stage 2.5 5.3L head from TSP would be plenty of head to get a 5.3L to run the rpm. If cheap is the idea along with a wide power band find an L33 or standard 5.3L, get some used 4.8L pistons, and use a well ported 862 casting head. If you want to get a 3.9 bore block just buy an LS1/6 block in the first place. The iron blocks will take the bore out from a 5.3L to a 5.7L easily, but that's stretching the liners on an L33 block and for no reason when they already make a block with that bore. You make the comment that you want to slow the piston speed down so as to not have to run forged parts and yet you made the point of running forged pistons and gen I sb rods. What you're doing is trying to simply make something different than everyone else which is what many out there try to do. Running 8 individual carbs will spark conversation when you open the hood and that's about it. There is no reason to re-engineer what already works fine. Stock stroke LS based motors will turn all the rpm that your valvetrain can handle. I'll happily compare the torque curve of my little 5.3L in my truck to your specialty build when you're done.

theastronaut

Zippy, you don't seem to understand the potential that IR intake maniflolds have over plenum manifolds. The engine has to be built with that type of intake in mind since an IR completely changes how the engine breathes. They're not a "conversation peice" or to draw attention at shows. If that's what I wanted I'd have a blower, two four's sticking out of the hood, and a huge scoop or something stupid like that. I'm not a show-off kinda guy; my other car is a sleeper VW bug that looks pretty much stock- you'd never guess that it runs as hard as it does. I hate "look at me" modifications on cars. Please go educate yourself on IR intakes before you bash them, there's a thread on here about them actually. I'll see if I can find the link.

I do appreciate the useful info about L33 blocks not being able to be bore to 3.90". That's the kind of info I'm looking for. I only posted about Gen 1 rods because I had read that they'd work and could be easily bought in the correct length for a 4.8 crank. I said I was new to LS engines, so please be a little forgiving of my ignorance.

I'd love to compare torque curves when it's done. That's the whole point of the IR intake. Added low-end drivability with a big cam that makes power up top too.

Here's that link:

https://ls1tech.com/forums/advanced-...tb-thread.html

dzus

At the risk of being roasted here also, count me in as another dinosaur that wants to see you build the IR LSx. Most people unfamiliar with their charm have just never driven one. While I was raised on carbs, I'm slowly warming up to the idea of running EFI. Every build I follow that starts out with webers, gets them dialed in, and then replaces them ITB's gains power, mileage and driveability. If that's truely the case, you'd be money ahead to skip the weber/dellorto's and just jump straight to the ITB's. Since you're building your own intake, the ITB's wouldn't necessarily have to be weber replacements, which are pricey. Last time I was at the junkyard I dug through the aluminum scrap pile and found a variety of throttle bodies that could be adapted for cheap. .
Have you read this info on tuning ITB EFI setups? While a megasquirt setup, it gives you a little primer on what is involved:
http://77e21.info/mstuning.htm
Aggragating the vacuum signals to a common point for the map sensor is key to success.
Background:
http://77e21.info/megasquirt.htm
Good Luck!

Ellesone

why not just lighten the assembly up?

why make smaller cubes and less power, I never understood that.

zippy

I'm very familier with them and have worked on enough of them to no be making my point on them by guessing. Almost every vehicle I've worked on with them with the exception of show cars/trucks has ended up being swapped out for something that is more simple and reliable after they've owned them for a bit. When everything is working perfect they are great under wide open...

I am oddly enough a fan of modified VW's. There are so many parts available for them now that you can really build some bad *** stuff with them. From your earlier post you are building a motor for it so taking in account that isn't in the car what motor/setup is currently in the car that makes it run so hard?

theastronaut

Zippy, It currently has a 1679cc that makes around 90hp and 115 tq. That's pretty strong for stock heads and less than 100cc displacement increase over the original dual port engines. I've got a couple friends who's 1776cc and 1835cc engines barely make that much power with more agressive cams and ported heads. I haven't run it yet but I expect it to run mid-high 9's on our 1/8 mile track. Not really that fast, but its runs much harder than expected for such a small engine with stock heads (no portwork) and a redline of only 5200 rpm. I had a chance to buy the engine (minus the carbs) for $1000 bucks with only 5000 miles on a refresh, so I jumped on it. The blueprinted block is worth nearly that much alone. I already had the Dellorto's from a 1600 so the jetting was nearly dead on to begin with.

Specs on it are:

Newer OEM VW block, blueprinted.
DPR 69mm forged/couterweighted crank.
Mahle thickwall 88mm cylinders/forged pistons.
Factory forged rods.
Engle FK-41 cam on 112 LC.
1.4 rockers.
Stock heads/valves.
9.6:1 CR.
Dual 36mm Dellorto DRLA's, 30mm venturis.
Vintage Speed stainless exhaust, 1.5" primaries.


Once I get my truck built I'll finish the turbo/EFI 2276cc stroker for the VW. I started building the '66 C10 and put a hold on the 2276 build.

So far I've got the longlbock nearly ready for final assembly. It has:

Lightened/knife-edged/smoothed/polished CB Performance 4340 Chomoly 82mm crank.
CB's forged 4340 H-beam rods, 5.4"
Weisco/Aircooled.net "Super Squish" 94mm pistons. Has squich/quench enhancing domes for faster burn.
Mahle Cylinders.
CB's CNC ported Wedgeport heads, matching ported intakes.
CB's forged/bigger diameter shaft rockers.
Block has been clearanced, lifter bores are sleeved with silicon bronze, welded behind #3 cylinder opening, main bearing webs ported for better internal breathing, bored for larger cylinders, perimeter fastener pads have been spotfaced for larger washers, drilled/tapped for oil filter lines, and crank bore/cylinder openings have been machined for correct alignment.

It will turn 7500+ rpm and make around 215-220 flywheel hp N/A, and the bottom end should hold atleast 20 pounds of boost. 325-350 whp should be doable on a milder street tune, and I may use water/meth injection to bump the boost up for the track. 400-425 whp on a track tune with water/meth should make for a wild ride in a car that only weighs 1,660 pounds! It will look completely stock- stock height, no body mods, and porta-wall whitewalls over M&H slicks on the original smoothie wheels. I'll widen the rear wheels to 6" with the added width to the inside of the wheel to keep it stock looking from the outside. Should be the ultimate sleeper.

That's partly the reason I'm not trying to make as much power with the truck engine as possible; the VW will be faster in a straight line even if the truck had 5-600 hp. No need to have two cars that fast, and the truck will be built to go around corners so it's not going to be set up to lauch hard on a dragstrip.

If you're interested, here's a link with some of the work I've done on the 2276cc's longblock.

https://www.facebook.com/media/set/?...3&l=6a2820ffcc


To stay on topic, I've decided on using a 4" bore block with a 4.8 crank to make 329 CI, since the L33 blocks can't be bored much. I bought two T-56's and two factory tach gauge clusters within a month so I've got to let my play money account catch it's breath before starting the hunt for a 4" block.