So you care about having the equipment in place and getting good gas mileage.
What I meant was... "emissions" from the point of view of simply having the equipment and being able to pass a visual inspection is very different from understanding what's coming out of the tailpipe.
Increasing compression will increase NOx emissions, but it sounds like you don't care about that. "Best gas mileage" could be accomplished with an open loop tune that runs lean at light throttle cruise, but that also increases NOx and CO emissions.
At the OE level, the catalyst would be tuned to deal with these different characteristics.
Well, what I want is the right equipment in place that gives me good gas mileage, low emissions (ULEV/PZEV would be nice to hit), and getting as much power as possible at the same time. Basically a decent balance between the three.
I have been starting to poke about to see if there's any way to run a wideband with the e38 ECM as well, so I could possibly run a lean burn cruise program.
The "visual inspection" part I don't much care about. as long as it looks like I have a cat, I will be fine if I ever get pulled over and the cop decides to look for a cat. But I don't just want a hollowed out cat. I'm interested in the real numbers, and seeing how the math works, both to learn something new, and to pick the right parts for the job. If I didn't care to learn anything, I could just as well go any number of the "easy" routes for an engine swap. But I chose to do what I'm doing with my swap, because it's a challenge, and nobody else is doing it.
Received the LS9 piston cooling jets today. Apparently they are made in Tunisia.
They look like this once installed:
I just need to find a shop to machine the block so I can install them, Still haven't heard back from SCAT or Callies on whether they can/will do a crank with the LS4 snout/flange dimension changes. Nor from Isky about a cam. But pushing forward (buying plenty of other things) anyway.
Yeah. The LSA also uses them, and has a slightly different oil pump configuration (not sure if it's just the spring, or what entirely), so I'll have to pick one of those up as well. They also have a check valve in them I think, which closes them off under maybe 25 or 29 PSI, or somewhere around there.
I think the LSA was the only Gen IV wet sump engine to get them. The new LT1 has them as well though (and sadly can't use the Gen V oil pump because it's just different enough to not fit on the LS engines). I don't know if the Gen V truck engines have them. The LT4 does, but it's a damp sump like the LS9.
Yeah, the dry sump design on the LS7/LS9/LT4 apparently isn't a true dry sump, as the pan still holds quite a bit of oil and it uses a wet sump pickup,
The primary characteristic of a "dry sump" is that the pressure side of the pump pulls from a tall narrow tank that doesn't uncover the pickup with lateral g's and that the scavenge side of the pump can stand pulling some air every now and then.
Wilwood has rotor hats that fit a variety of drum-in-hat parking brakes.
EBC also has a full selection of rotors and pads for the Matrix/Vibe platform. And Brembo has a kit as well. The Brembo might be front only though, I'd have to look it up again. I used the EBC catalog (I've got EBC rotors/pads on my Avalanche) and AutoZone for rotor dimension info. I will probably end up with EBC rotors and pads, as I quite like them, and they have been performing excellently on my truck. The main thing I need to do a little more research on with the brakes, is calipers. The stock calipers might be more than fine for the Fiero, but they're single piston and I don't know what diameter piston is used. I need to get the piston diameter and compare it to the stock Fiero brakes, and other caliper options for the Matrix/Vibe brake setup.
Looking for an aftermarket SFI damper, but it seems nobody offers one for the LS4 snout and accessory drive. Given that, it seems like I can just use the standard length snout on the crank, and then use an ATI Super Damper for an LS2 or such, and go with a custom water pump, similar to what Dan86GT did on his LS2/6t75 swap. The only other accessory I will be driving off the balancer is the alternator. So I guess it will just be the alternator now.
It's slightly annoying, because the front will stick out a little more than the stock LS4. But on the other hand, it should make it a little easier to get a forged crank from Callies (if I can ever get a response from them), as I will have to use the standard post length for the balancer. On the forged front, I still haven't heard anything from Callies, and SCAT will only do full billet which is like $3500 for just the crank. Going to call Callies tomorrow and see if I can get a balanced rotating assembly made up. Lighter rotating assembly, lighter balancer, and the lightweight flywheel should make for some very nice throttle response and high RPM spins, and combined with the forged pistons, higher compression, and valvetrain, should make for a very nice and smooth powerband.
[This message has been edited by dobey (edited 03-14-2017).]
Isn't the LS4 snout just the standard snout cut down? Couldn't you get a normal crank and have it modified locally?
Yeah, but if I'm going to buy a custom forged rotating assembly, i'd rather not have to modify it further and then go get it rebalanced due to material removal. Plus it's one less dimension that I'll have to explain and convince someone else of being correct and shorter than the standard LS snout. Instead, I'll just need the smaller flange thickness, shorter stroke, and longer rods. Should be pretty easy to do.
ATI doesn't have a Super Damper for the LS4, so to have the shorter snout would mean either using the stock damper, which has been shown to fail under stress of high RPM, or trying to convince ATI to make one for the LS4 at a reasonable price.
Originally posted by dobey: Yeah, but if I'm going to buy a custom forged rotating assembly, i'd rather not have to modify it further and then go get it rebalanced due to material removal.
I can't see any reason at all why you would need to re balance a crank after just shortening the snout.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Originally posted by ericjon262: I can't see any reason at all why you would need to re balance a crank after just shortening the snout.
Removing metal may affect balance, however small an effect that may be. If I'm going to spend $3K+ on a rotating assembly, I'd want to be sure it's in proper balance before I install it. And if I'm going to pay $3K+ for a rotating assembly, I'm going to have them make the crank the correct size when they make it, not after I receive it.
[This message has been edited by dobey (edited 03-14-2017).]
Been looking a little further into the balancer situation, and I think I'm going to need the longer standard post and balancer setup anyway.
This is the VVT front cover. Notice the area where the cam gear sticks out further than the non-VVT covers due to the phaser, and is flush with the area that covers the timing gear on the crank.
The LS4 is pretty close to the front cover, and I don't think it will clear the Gen IV VVT setup. The Gen V engine has the cam solenoid bolts and wiring routed differently, and would make room, but the Gen V timing cover is quite a bit different and won't fit on the Gen III/IV engines, so that's not an option either.
Here's an image that fieroguru took of the LS4 balancer and front cover. Notice how close the balancer is to the cover, and where it would interfere with the cam sensor and VVT solenoid wiring and bracket.
Looks like I will have to use the longer snout and have the balancer be out a bit further, if I want to use the VVT (which I really want to do).
Removing metal may affect balance, however small an effect that may be. If I'm going to spend $3K+ on a rotating assembly, I'd want to be sure it's in proper balance before I install it. And if I'm going to pay $3K+ for a rotating assembly, I'm going to have them make the crank the correct size when they make it, not after I receive it.
Anyway, I'll go out to the garage and get exact measurements for the flange thickness and post length, before I start calling people today.
Didn't you buy the rods and pistons separately? Unless you're getting a billet crank cut to your specific bobweight, you'll need to have it balanced ANYWAY... I was under the impression you were looking for someone's shelf forging.
Originally posted by Will: Didn't you buy the rods and pistons separately? Unless you're getting a billet crank cut to your specific bobweight, you'll need to have it balanced ANYWAY... I was under the impression you were looking for someone's shelf forging.
What stroke are you going for?
I haven't bought the pistons and rods yet. Callies and SCAT will sell fully balanced rotating assemblies. They also do custom cranks. I was hoping to get a fully balanced forged (not billet) assembly to fit the LS4 with the 4.8L stroke. But I've not had any luck yet.
I was wanting to de-stroke to the 4.8l stroke, which is 3.268" and has 6.275" rods. Nobody has a shelf forging for the 4.8L dimensions though. Since I won't be able to use the LS4 balancer anyway, due to VVT and having an ATI balancer made to fit would be another custom thing, I'm thinking I'll just go back to the stock 5.3L stroke and rods, as they are the same as the 5.7, which everyone does have parts stocked for. With that, I should be able to order a rotating assembly more easily, and will just need the flange cut down to a smaller thickness.
The idea to drop the stroke down and build a 4.8l was to reduce low-end torque and increase RPM range, to make more use out of the F40 gearing and as a slight safeguard against damaging the trans, before I'd learned about the Gen IV VVT system and decided to go with that. Since I've decided to go with VVT, I've decided to go with a lightweight forged rotating assembly, and since the LS4 accessory drive will interfere with the VVT equipment, the reasoning I had for lowering the displacement doesn't matter as much any more. Going back to 5.3L it will be a bit easier to find parts for, and going with a forged crank, I can have the longer snout to solve the interference problem with the balancer. I'll lose a little clearance when mounting in the cradle, but since it's an 87, I think I have a little more room to play anyway, than the 88 does. It might be a problem if I try to build a hybrid module for it in the future, but I won't worry about that right now.
As far as the crank dimensions go, every site talking about the dimensions of the LS4 crank in relation to the standard LSx crank, says the flange is 3mm thinner and the snout is 10mm shorter. I was just in the garage taking measurements on my LS4 crank and comparing them to the crank in the 4.8L short block I have sitting in my garage, and I think those have been getting quoted backwards. The difference in the snout length is not really visible without taking an accurate measurement, but the flange thickness is very much visibly different.
[This message has been edited by dobey (edited 03-14-2017).]
OK. Just talked to someone at Callies about taking their standard LS1 crank and just trimming the flange back to the thickness for the LS4. Apparently they never actually got my e-mails, so not sure what's up with that. He said he'll have to do a little research to see what the difference in the dimensions are on the flange, and will have to get back to me.
Hopefully they can turn the flange down on a standard LS1 Compstar crank they offer, and build me a rotating assembly off that, with some H-beam rods and the Wiseco pistons.
Just called Proform about their Tall Aluminum Valve Covers too, to see if they have them in unfinished natural aluminum, and what the thickness of the top of the cover is. They seem to only have them in polished and couldn't tell me what the thickness is. Even the patent for the valve covers (really?) has literally no information about the vlave cover. It's just six line art drawings of different views of the cover, and a statement of "we claim this drawing." :-/
The guy on the phone said he thinks they're only like 0.100" thick though. Which is probably not enough to mill them the way I wanted to.
Why do you need a forging? The production LS cranks are immensely strong and the 4.8's is the strongest. The stock 4.8 crank and rods can be booster to over 1200 HP and 7000 RPM.
Originally posted by Will: Why do you need a forging? The production LS cranks are immensely strong and the 4.8's is the strongest. The stock 4.8 crank and rods can be booster to over 1200 HP and 7000 RPM.
I don't really need them. But the weight loss will be good, even if it's not a huge amount.
I don't know that I'd say the 4.8 crank/rods are stronger, but more it's just that the shorter stroke results in less pulling force on the rod and piston, which normally pulls them apart when over-revving. I suppose that makes a good reason to drop the displacement too.
Anyway, will see what Callies says and go from there.
I don't really need them. But the weight loss will be good, even if it's not a huge amount.
I don't know that I'd say the 4.8 crank/rods are stronger, but more it's just that the shorter stroke results in less pulling force on the rod and piston, which normally pulls them apart when over-revving. I suppose that makes a good reason to drop the displacement too.
Anyway, will see what Callies says and go from there.
shorter stroke mean the rod and main journals overlap more, which makes the crank stronger, how much stronger, IDK.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Originally posted by ericjon262: shorter stroke mean the rod and main journals overlap more, which makes the crank stronger, how much stronger, IDK.
They're the same material, so they're the same strength, I would think. But with shorter stroke, the piston speed is lower, which means less force is exerted on the crank. I haven't measured (or seen any measurements anywhere), but I think the webs are the same size on the 3.625" and 3.268" stroke OEM cranks, but the pins are just positioned differently for the different stroke.
They're the same material, so they're the same strength, I would think. But with shorter stroke, the piston speed is lower, which means less force is exerted on the crank. I haven't measured (or seen any measurements anywhere), but I think the webs are the same size on the 3.625" and 3.268" stroke OEM cranks, but the pins are just positioned differently for the different stroke.
nothing to do with piston speed, it has to do with material thickness, it's the reason the 400 SBC got bigger journals.
I threw together a quick sketch to explain what I mean.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Originally posted by ericjon262: nothing to do with piston speed, it has to do with material thickness, it's the reason the 400 SBC got bigger journals.
I threw together a quick sketch to explain what I mean.
It has to do with both, but the crank is one of the last things to break in an LS engine anyway, especially one that's N/A. Looking for pics of broken LSx cranks, all the ones I've found seem to be breaking just behind the first main journal, and due to extra stress of a roots blower on the snout, causing the first main journal to rub the bearing, and result in the thinner material between the first counterweight and first rod journal to shear. It's very unlikely to break an LSx crank at any of the inner rod journals, unless the rotating assembly is seriously out of balance, bearing failure, or some other incredibly unlikely thing.
The real weak point is the rods. The longer rods themselves are probably slightly weaker, but the reduced stroke results in lower piston speed, which results in significantly less pulling force on the rod/piston, at a given RPM, so it's less likely that it will break, given the RPM range of stock LSx engines. There are two main ways the rods fail. They get bent, or they get pulled apart. Over-revving to the point where the pulling force on the rods is greater than the material strength, is what pulls them apart. Too much power, or contact at the top of the stroke, is usually what bends them.
The more RPM I can get out of the engine, the better, and the more useful the gearing of the F40 trans will be. Stronger and lighter rotating assembly will certainly help with that, and provide insurance for future mods if I decide to boost or do some other crazy thing. Between the crank, rods, pistons, and balancer, I'll be able to save almost 20 lbs off the rotating assembly. I'm not sure what the weight of the flexplate and filled converter is for the stock LS4, but hopefully the aluminum flywheel and clutch setup is also saving a few pounds.
Piston acceleration is crank loading not crank strength.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Originally posted by ericjon262: Piston acceleration is crank loading not crank strength.
Right. I was just reiterating that the crank strength in an LSx engine is pretty much irrelevant when one isn't using a blower. Stronger material is a nice bonus of having a forged assembly, but it's not why I am looking at possibly using one. The weight savings and having a pre-balanced assembly delivered to my door are the main reasons. Added strength is a nice benefit. Less rotating mass means more RPM range and better MPG, depending on tuning, both of which are things I'm going for with the build.
It's well known and generally accepted that production LS rods are good for 7000 RPM in drag racing usage; ARP rod bolts are insurance, not preventive maintenance.
[This message has been edited by Will (edited 02-02-2015).]
Right. I was just reiterating that the crank strength in an LSx engine is pretty much irrelevant when one isn't using a blower. Stronger material is a nice bonus of having a forged assembly, but it's not why I am looking at possibly using one. The weight savings and having a pre-balanced assembly delivered to my door are the main reasons. Added strength is a nice benefit. Less rotating mass means more RPM range and better MPG, depending on tuning, both of which are things I'm going for with the build.
Rotating mass has basically nothing to do with MPG.
Piston weight has the largest effect on max RPM, followed by piston pin weight. Rod mass doesn't have a very big effect on max RPM, as the majority of the weight of the rod is in the big end and that is rotating weight, not reciprocating weight.
Moment of inertia of the rotating assembly affects ACCELERATION of the engine. Also, the entire rotating mass of the engine is a small fraction of the engine speed MOI because the flywheel and clutch have a much larger diameter than the crank counterweights.
Here are some calcs on how to figure out how to lathe turn crank counterweights to achieve maximum MOI reduction when re-balancing for a significant bobweight reduction: http://www.realfierotech.co...topic.php?f=3&t=4522
It's well known and generally accepted that production LS rods are good for 7000 RPM in drag racing usage; ARP rod bolts are insurance, not preventive maintenance.
Yes. I have read that Hot Rod article multiple times, and seen several similar builds. I'm looking to go a fair bit higher than 7000 RPM though. If I can, I'd like to be able to push the fuel cut on my tune out to 9000 RPM, and I'm trying to squeeze as much MPG out of it as possible.
Although, I am enjoying the slight irony of you now telling me to not bother with forged bottom end, while previously you were trying to convince me to sleeve it and build a 5.7.
Yes. I have read that Hot Rod article multiple times, and seen several similar builds. I'm looking to go a fair bit higher than 7000 RPM though. If I can, I'd like to be able to push the fuel cut on my tune out to 9000 RPM, and I'm trying to squeeze as much MPG out of it as possible.
Although, I am enjoying the slight irony of you now telling me to not bother with forged bottom end, while previously you were trying to convince me to sleeve it and build a 5.7.
I was under the impression you wouldn't be after conflicting goals. Sleeving and destroking keeps good breathing and RPM capability, but the slightly larger displacement helps keep RPM required to make power and fulfill what the heads can deliver down to a reasonable level.
Go read some stuff in the Advanced Tech section of www.speedtalk.com People ask regularly about building 10,000 RPM engines there and get "informed" about how difficult it really is. I'm not sure you understand what building a 9000 RPM engine really means. To be reliable at that RPM, you're trying to use production derived parts to build a Winston Cup engine. That's a HUGE money sink.
Do you have a throttle per cylinder intake in your plan? That's what it's going to take to make a 9000 RPM engine even remotely civil enough that MPG is even in your vocabulary when you drive it.
Are aftermarket heads in the plan too? At spring loads high enough to turn 9000 RPM with a high lift cam, there's a real possibility of pulling rocker bosses out of production heads.
You'll need 1/2" pushrods to run those spring loads at that speed. Because of their enormous internal volume, they become very heavy when full of oil, so you need to look into non-oiling pushrods and alternative means of top end oiling.
The implications and costs snowball VERY quickly when you talk about that much RPM.
Have you calculated how much oil pressure you'll need to overcome centrifugal force at the main journal surface at 9000 RPM?
[This message has been edited by Will (edited 02-03-2015).]
Originally posted by Will: I was under the impression you wouldn't be after conflicting goals. Sleeving and destroking keeps good breathing and RPM capability, but the slightly larger displacement helps keep RPM required to make power and fulfill what the heads can deliver down to a reasonable level.
Go read some stuff in the Advanced Tech section of www.speedtalk.com People ask regularly about building 10,000 RPM engines there and get "informed" about how difficult it really is. I'm not sure you understand what building a 9000 RPM engine really means. To be reliable at that RPM, you're trying to use production derived parts to build a Winston Cup engine. That's a HUGE money sink.
Do you have a throttle per cylinder intake in your plan? That's what it's going to take to make a 9000 RPM engine even remotely civil enough that MPG is even in your vocabulary when you drive it.
Are aftermarket heads in the plan too? At spring loads high enough to turn 9000 RPM with a high lift cam, there's a real possibility of pulling rocker bosses out of production heads.
You'll need 1/2" pushrods to run those spring loads at that speed. Because of their enormous internal volume, they become very heavy when full of oil, so you need to look into non-oiling pushrods and alternative means of top end oiling.
The implications and costs snowball VERY quickly when you talk about that much RPM.
Have you calculated how much oil pressure you'll need to overcome centrifugal force at the main journal surface at 9000 RPM?
I don't think they are conflicting goals. A 5.3L only needs about 845 CFM at 100% VE at 9000 RPM, or about 105 CFM per cylinder on a V8. The stock #243 heads can flow over 250 CFM at 0.500-0.600 lift, the stock LS2 intake can flow about 230 CFM at the runner for those lifts, and the LS2 throttle body can flow over 1000 CFM. At 83% VE, the required air flow drops to about 700 CFM. I will be porting and/or polishing all three of those pieces, and given the numbers there, they should be able to provide enough air for the RPM. I don't know yet if the stock LS2 injectors can provide enough fuel. I will have to do more research there.
I'm not trying to build a Cup engine that runs at such high RPM for extended periods of time. The RPM, power, and MPG numbers I want to hit are just goals. If I can hit them, then awesome. If not, then awesome too. A lot of what I'm doing in the build is just to have a look at the engineering challenges involved and to experiment, and because nobody else has done it. Nobody has done a VVT retrofit. Nobody has a forged rotating assembly in an LS4 block. If Callies will build me a rotating assembly, then they'll have the right dimensions in their system, and may even create a part # reference for other people who might want to build a forged LS4 for race applications.
As for a high lift cam, I'm not sure what you consider high exactly. I'm not looking to go big with the cam. I'm retrofitting VVT, so I have to do a balancing act between lift, duration, and possible interference with the piston, when choosing the cam lobes and separation angles, anyway. I'm looking at going around 0.550 max lift at the valve. I'll be using roller rockers, and Isky Tool Room beehive springs that are 360 lbs @ 1.175". At 1.25" I expect that will be somewhere around 280-300 lbs. Will also be getting anti-pump-up lifters to help with higher RPM loads, and some pushrods (haven't decided on which to get yet).
I don't know how much oil pressure I'll need at that point yet. I do know the oil pump is another thing I need to look at more soon, particularly with the addition of the piston squirters. Do you have a formula to calculate the required pressure at the main journals?
A 5.3L only needs about 845 CFM at 100% VE at 9000 RPM, or about 105 CFM per cylinder on a V8.
It doesn't work that way. You haven't factored in the duty cycle of the intake valve. Say your intake duration (at .050) is 240 degrees. That means that your intake valve is open 240 of the 720 degree cycle... You actual flow demand is three times the average or 315 CFM... AVERAGED through the valve event. Now you need to convolve your flow curve and lift curve to integrate how much air actually gets through your valve during the valve event... it's much less than your peak head flow because the valve is only at peak lift for a short portion of the valve event.
You're going to need SOOOO much cam just to meet the airflow needs that you'll have no room for VVT unless you have valve reliefs so deep they drop your compression far enough to use a turbo.
quote
Originally posted by dobey:
I don't know how much oil pressure I'll need at that point yet. I do know the oil pump is another thing I need to look at more soon, particularly with the addition of the piston squirters. Do you have a formula to calculate the required pressure at the main journals?
Yeah, I do need to see how much air is actually going to get through the valve. It's a lot of numbers I need to play with there, since I don't have an exact cam in mind at the moment yet. I guess I can start with the stock L92 cam to see what it can do. It's hard to guess what various cams are doing though, since nobody publishes full lobe profile information, and only a few numbers.
I really need to write a program to draw pretty cam profile graphs, along with piston and cam phaser motion, and plug lots of numbers into it to see what the best solution will be for me. At least for that part, I pretty much have, or can reference easily, all the math I need to do.
But yeah, I don't know the math for the oil pressure calculations. I'm enjoying the discussion though.
Interesting thread; I'm especially enjoying the engine build, but still wondering what you're working towards for a flywheel and clutch - any developments there? I assume your F40 is being cut out for a stock LS4 starter... GP
Interesting thread; I'm especially enjoying the engine build, but still wondering what you're working towards for a flywheel and clutch - any developments there? I assume your F40 is being cut out for a stock LS4 starter... GP
I'm cutting the bell housing and making a pad for mounting the starter in the correct position for the LS4, yes.
[This message has been edited by dobey (edited 03-14-2017).]
