Knurled. said:
Just to piss on the electric fence a bit, there is a thread on Speed-Talk right now about what it would take to build an 800hp LS3 for endurance racing, and right off the bat it is accepted that the OE engine block is not good enough at these power levels.
https://www.speed-talk.com/forum/viewtopic.php?f=1&t=58787
Speed-Talk is chock full of lots, and lots, and lots of high performance knowledge, from people who do the building and the testing and the experimenting. I see some GRM faces there too.
Within minutes of you posting this, there is a post in that thread suggesting that the block is plenty robust for that power.
Either way, I think that will turn into an interesting discussion and I shall follow it. I'm going to try not going down the rabbit hole on that forum now.
The fascinating thing about LSX design when it comes to endurance is that there are so many ways to achieve that kind of power. Tons of bore and stroke combos combined with displacement vs. revs vs. boost. Not that other engines don't have these options, but the LS has a massive aftermarket so all these parts are already on the shelf and/or in the yard.
In reply to ProDarwin :
I saw that too. And it is interesting that the commentor spoke of LS9 engines, with Darton sleeves, and not LS3 blocks. I am not sure how different an LS9 and LS3 are (they are both the same bore, I know that much) but resleeving a block is not simple or cheap... maybe makes sense if you have a VNC at your disposal so you can load up a block, punch some buttons, and have it mill out the existing cylinders while you go do something else (like count money) but that is far beyond OEM, let alone "junkyard block".
Lof8 said:
E85 is good in a lot of ways, but you burn a lot more of it than gas. The injectors, pump, etc generally need to be upgraded to handle the higher flow...and you have to pit more frequently.
I've posted my experience with E85 in my pickup. Yes I have flex fuel so I can switch back and forth or partial or however the mood strikes.
Normal mileage is about 22.xx mpg of unleaded regular. Right now that is selling for about $2.69 a gallon.
Premium unleaded sells for $3.39 a gallon or $3.64 for non oxygenated premium. ( not legal for use in ordinary cars) * it's been more than 30 days since I checked that price. However The truck only gets less than a mile per gallon better maybe 23 mpg.
E85 sells for $2.09 a gallon.
the problem I have with E 85 is it is so hard not to floor it and smoke the tires or feel some serious acceleration because it adds about 10% more power.
However, if I keep my foot out of it and drive normal It costs me about 2 mpg.
Here is the math, I save almost $12 a tank using E85 but get 2 mpg less. So it costs me about $4.18 worth of mileage. I net out a shade less than $8 per tank when cost and mileage are figured together.
That is on the street. You need to understand E85 isn't always 85% ethanol. It varies. Legally it can be as low as 51% ethanol. To as high as 85% ethanol.
The formula for 85% ethanol is you need 60% more fuel. So clearly the pump grade I buy is likely closer to 51% than 85%.
On the other hand the computer is pretty smart it knows that with 114 octane of ethanol it can advance the timing which helps get better gas mileage.
There is a connection with the circle track crowd who use it for the extra 10% more power it gives, the cooler, cleaner running, and the more life they get out of a engine. plus lower cost.
You need to bring sealed gas cans to denature it in order to buy it legally. The only real source for sealed gas cans are race fuel suppliers like VP fuels etc. you need 2% gasoline to legally denature alcohol enough to avoid the booze tax.
However the savings is significant. It's purchased directly at the source. So no shipping, no markup, and to 114 octane alcohol you add real racing fuel you can easily have more than 110 octane!!!!! Per 55 gallon drum.
Knurled. said:
In reply to ProDarwin :
I saw that too. And it is interesting that the commentor spoke of LS9 engines, with Darton sleeves, and not LS3 blocks. I am not sure how different an LS9 and LS3 are (they are both the same bore, I know that much) but resleeving a block is not simple or cheap... maybe makes sense if you have a VNC at your disposal so you can load up a block, punch some buttons, and have it mill out the existing cylinders while you go do something else (like count money) but that is far beyond OEM, let alone "junkyard block".
True. I would call it a modified block. Not a stock block, but its not an aftermarket design either. Still impressive.
In reply to ProDarwin :
Take a look at a Jaguar V12 block. Then look at a top fuel block. Except for the number of cylinders they really look alike don't they?
Giant size mains, massive rod bearing sizes. Pressed in cylinder sleeves. Big heavy forged steel crankshaft made with EN 40 steel then hardened enough that normal crank going equipment won't do the job.
54 head studs that most of which go right down into the mains. Hardware that rivals ARP.
In reply to frenchyd :
I run champcar in an e85 burning miata. We burn about 25% more fuel than when we ran gas. And we pit more often to refuel.
In reply to Lof8 :
Yes you will, on the other hand you're running cooler aren't you? With the 5 minute mandatory pit stop for fuel is the gain worth the added time to pit?
I've done the math and it will be a serious handicap. For a thirsty car like a Jaguar.
When the Jaguar factory team ran against the might of BMW in Group A touring cars. The Jaguars has to really press to make up the time.
It was really great racing.
In reply to frenchyd :
It does run cooler, but heat was never a real problem for us. My opinion is that running e85 was not worth the mpg handicap. Unfortunately I'm outnumbered by my teammates who think otherwise. Another drawback was bringing home 120 gallons of e85 after an early retirement because there was no e85 near the track and we had to bring enough fuel for the whole race.
Paul_VR6 said:
The self learning is only as good as how you configure the AFR table and how long you let it run like that. If you have some of the base settings off, or encounter things like misfires, it can go off script pretty easily.
It's good advice going one sensor, output, etc at a time. Digest in little bits.
That's where I'm sure I'll needs lot of guidance. When I turbo'd my first V12 I had some real help from a friend who wanted to go racing with me. In fact the whole idea of Turbo's was his.
I had the car but wanted to retro it back to carbs because those I understood and could make work.
He went with me and showed me how easy it was to sort good used turbo's from junk. It was his idea to use the cold start injector to add fuel during boost and he showed me how to richen up the regulators enough to deal with 2 pounds of boost.
We were both devastated when we were told they wouldn't allow us to race it that way.
Once I found we could run without penalty I called him to see if he wanted to join me but He's very non committing. It's all. "We'll see" and "get it running and I'll look it over". Very much the definition of a once burned twice shy guy. Well to be fair he's nearly as old as I am and maybe he doesn't have the drive anymore.
Lof8 said:
In reply to frenchyd :
It does run cooler, but heat was never a real problem for us. My opinion is that running e85 was not worth the mpg handicap. Unfortunately I'm outnumbered by my teammates who think otherwise. Another drawback was bringing home 120 gallons of e85 after an early retirement because there was no e85 near the track and we had to bring enough fuel for the whole race.
I can understand that. I don't really need the extra power the E85 gets. But I need the lower cost, plus it's part of my plan to deal with heat rejection.
If I do this my plan is to get it running reliably on the street, then take it to a SCCA Track night or two hopefully with potential drivers to evaluate. A local club will allow cars conforming to Champ car rules to run with them.
That will put the car on one of the tracks that Champ car runs on. I'll be able to see how hard I'll have to push it to run consistently competitive laps.
If at any time during those events there is a serious mechanical issue then I guess I won't be entering. Nobody will be out any money and I'll just slink off.
As far as any left over fuel? My truck has flex fuel, I'll just burn it during the tow home. But this is corn country here. There is plenty of E85. So I assume a local station or two will have it.
E85 is amazing as long as you have a good (fresh) supply for it. Test often for water uptake and always store in METAL cans. $/mi will be under what it costs for VP MS105L (unleaded) but make 20% more power on average on turbo setups.
frenchyd said:
In reply to ProDarwin :
Take a look at a Jaguar V12 block. Then look at a top fuel block. Except for the number of cylinders they really look alike don't they?
Not unless Jaguars are solid metal with no water jackets.
Anyway, an engine with a life expectancy measured in single-digit seconds is not a good benchmark for an endurance application.
In reply to Knurled. :
You're right , the Jaguar has water jackets so it won't be asked to make 9000 horsepower.
Heck, I'm not even going to ask it to make 1000
350-400 is plenty
Considering the LeMans wins making up to 830 horsepower running on French pump gas I suspect it's plenty strong enough.
Paul_VR6 said:
E85 is amazing as long as you have a good (fresh) supply for it. Test often for water uptake and always store in METAL cans. $/mi will be under what it costs for VP MS105L (unleaded) but make 20% more power on average on turbo setups.
It's nice to live where there are so many ethanol plants. One plant south of the twin cities sells ethanol direct to racers, The manager is a race fan and willing to go to the extra effort required. You must bring a sealed can of fuel to denature it.
Everything is done on camera and there is a fair amount of paperwork required. But it goes into drums and then is denatured. Then sealed. Since there is no road tax collected or federal tax the number of people who have access is limited.
Robbie
UltimaDork
10/16/19 4:38 p.m.
In reply to frenchyd :
What everyone is trying to say about e85 is that in endurance racing you will need to stop more often. And that is BAD!!! The need to use stock or stock sized fuel tanks has been mentioned already.
Zero mph for any amount of time really hurts your average speed.
A 400 hp v12 running e85 with stock size xjs fuel tanks is not going to be able to run for 2 hours without a refuel
From my memory, our e36 (at half the 400 hp but similar fuel tank volume) could run just about 2.5 hours on the full tank of premium. And we were not elite drivers by any stretch.
In reply to Robbie :
I think if you go back and read earlier posts I've mentioned that.
Jaguar's are already thirsty. Using additional fuel is going to make it worse. Luckily Jaguar's stock gas tank is 24 gallons, the maximum allowed.
The reality is that it's extremely unlikely I'll be able to even get 2 hours out of a tank
There is a solution. The early Jaguar's recorded about 9 mpg driving in a civilized manner. Later HE's could get almost 20 mpg.
The Jaguar XJS that ran that way tried to use the HE engine. Without richening the fuel mixture the HE normally produces a stratified charge. At peak RPM for extended periods the head gasket blows.
they blew the head gasket (s) twice.
Robbie said:
In reply to frenchyd :
What everyone is trying to say about e85 is that in endurance racing you will need to stop more often. And that is BAD!!! The need to use stock or stock sized fuel tanks has been mentioned already.
The year after I was involved with Lemons, they incorporated a rule that said drivers had to change out every hour (or something like that)
Year prior, the time I was involved with had won in part on the strength of pit strategy - very long driver stints and minimal time spent not on course making laps.
The fuel efficiency at peak torque of engines does not vary that much. The efficiency comes in at part throttle conditions & the efficiency of the chassis.
400hp is going to take a lot of fuel no matter what engine it comes from.
HIn reply to Knurled. :
That's a valid point. If I recall LeMons doesn't have the 5 minute pit stop rule.
Plus once an hour makes it more fun then grinding out 2+ hour stints.
Just as a note on comments I've read and heard. Lemons seems to have more poorly experienced/ Skilled drivers than Champ car.
I don't know how valid that is though, I've been to several Chump/Champ car races and the level of drivers seemed OK to me. I've never attended a LeMons race though.
In reply to ProDarwin :
That's true, as far as it goes. The idea is to get to the front pack and drive at less than 400 horsepower. If it takes 230 horsepower to run up there won't fuel usage be around the same as a 230 horsepower car at full throttle?
frenchyd said:
In reply to ProDarwin :
That's true, as far as it goes. The idea is to get to the front pack and drive at less than 400 horsepower. If it takes 230 horsepower to run up there won't fuel usage be around the same as a 230 horsepower car at full throttle?
Its going to vary based on engine, and this is one area modern engines really excel (and one of the reasons modern cars get so much better mileage). Modern engines have flatter BSFC in the mid range and can run at near peak efficiency over a much wider range of RPM/Throttle.
Edit: Its actually not as bad as I suggested. Efficiency peaks where torque peaks. Your best bet if you want to make partial power and still retain near-peak BSFC is still to run at WOT and just run in higher gears. In that case it will actually remain quite efficient.
Running at part throttle though would not be good.
In reply to ProDarwin :
Funny, the HE 1981-1996 which gets nearly 20 mpg hauling around a 46xx pound car will have problems At prolonged wide open throttle. It's a stratified charge that runs at the edge of detonation, in order to maximize fuel mileage.
In reply to Knurled. :
What year was that? I have little kids so haven't raced in a few years but at least as recently as 2016 there was no maximum stint rule.
I love the 2 hour stints. I'm barely getting into my groove at the 1 hour mark. I've banged out a 2.5 and nearly 3 hour stint before and had a blast doing it. In car hydration becomes important.
Driving style can also drastically affect MPG as well in our experience. At Daytona with a bunch of time attackers driving (i.e. guys whose primary objective is to set a fast lap) the Honda fit we rented could get about 60-65 minutes before the fuel light came on and you needed to pit on that lap or would fuel starve. (meanwhile the slower cars in our class were doing 2 hour stints and gaining 2 laps on us every other hour)
We figured this out mid race and started driving in a way to help save fuel. tucking behind other cars even if they were slightly slower around the banking/straights. coasting up to corners rather than jamming on the brakes. etc. Driving in a conservative manner we could stretch fuel out to about 85-90 minutes and according to data once drivers got the hang of that and could link up with a car running similar lap times they were only about 1 second off their best pace while also extending fuel nearly 50%. (the draft is real at Daytona) losing 1 second per lap compared to losing 5 minutes multiple times is an easy choice to make.
All that to say, I wouldn't get terribly hung up on fuel yet, build the car, then do testing and figure out what your drivers do and how long fuel lasts with that particular nut behind the wheel.
Which does bring up another fun mental math exercise you could consider.
If 200hp was good for 2 hours while 400whp was good for 1 hour between stops how much faster per lap would you need to go to make up for a 5 minute pit stop every other hour? using Daytona (because the math is easier) it's about a 2.5 minute lap on average so a 5 minute champ mandated pit stop costs approximately 2 laps (plus the time you fall behind going pit lane speed)
Car A which can do the full 2 hours at 2.5 minutes per lap will do 48 laps in 2 hours.
Car B doing 1 hour stints at 2.5 minutes will do 24 laps in hour 1, lose 5 minutes to pit stop and do 22 more laps in the remaining 55 minutes.
So in a 14 hour race:
Car A makes 7 pit stops losing 35 minutes (14 laps) would hypothetically do 322 laps.
Car B makes 14 pit stops losing 70 minutes (28 laps) would hypothetically do 308 laps.
Car B with turbo to make up time but still doing 1 hour between fuel stops makes 14 pit stops losing 70 minutes (28 laps) but averaging a time of 2:23 per lap would wind up doing 322 laps and contending for the win.
So the real question is, how do you make a turbo jag 7 seconds per lap faster for 14 straight hours than a 200hp ex-Bspec honda fit racecar? If that sounds like it should be no problem, then I suspect you may very well have stumbled onto a winning formula.
