Trying to keep Frenchy on topic here.
This is a basic tutorial for you.
Trying to keep Frenchy on topic here.
This is a basic tutorial for you.
I'll plug borg warners matchbot program, is it also allows you to overlay changes to fuel type and a multitude of other parameters beyond compressor map. Obviously it won't have non-borg Warner applications but you can pretty effectively ballpark similar size applications and fudge the effectiveness within a map at various rpms to get a fairly clear picture
In reply to Stampie (FS) :
Thank you Stampie. I've got basically the same charts in my various turbo charging books. Luckily for me some of them fhelp me on how that applies to me.
What none of them seem to answer is which pair of eBay turbo's has been decent? I go on EBay and the same size turbo can cost $87 to $1800. It seems like there are an endless variety of brands. Now if I was a professional racer I doubt I'd be looking at an $87 dollar turbo. But for something like the challenge or Chump car maybe that's not so silly.
How am I to know?
That's why I asked the Nelsons for guidance. I liked what he did with changing the timing of camshafts. I won't have that ability because both my intake and exhaust is on the same cam. But it gives me a direction I can follow when I regrind my cams.
Maybe the trade off is less lift and duration for better timing of events. I'll know better when I run some of those options through the computer. The Short stroke of the V12 compared to the much longer stroke of the 4200 isn't going to be a 1 for one but it does give me a clue. Which way to try.
In reply to captdownshift (Forum Supporter) :
Link for Frenchy
https://www.borgwarner.com/aftermarket/boosting-technologies/performance-turbochargers/matchbot
In reply to frenchyd :
We have a pair of these on the Nova. It has a 6.0L. they work great. Makes about 900whp. From the time you foot hits the floor to 18 psi is like half a second
In reply to TheV8Kid :
Man, that's a lot of gain for a bit mor than a bill apiece! Do you figure a handy cheapskate could fab up exhaust for that for a few hundred or less?
I have a basicly stock 460 carb. engine that would not mind a bit of psi to offset horrible exhaust ports!
In reply to 03Panther :
Yeah. It's not hard. We spend a lot of time getting every ounce out of what we got, but you would be surprised at how crude you can get away with.
its been 35 years since I cared about squeezing ever last drop out of a car or bike... not that I was that successful at it even then. You guys are VERY humbling to me!
Now I care about a nice blend of enough power to not be boring, the best MPG I can, considering, and dependability.
In reply to TheV8Kid :
Any details on the rest of the set up?
TheV8Kid said:In reply to frenchyd :
We have a pair of these on the Nova. It has a 6.0L. they work great. Makes about 900whp. From the time you foot hits the floor to 18 psi is like half a second
Thank you. That's the helpful information I was looking. I noticed that brand when I was scanning through various turbo's trying to pick a winner.
Any idea of how long they last?
The cheap turbos seem to hold up OK at low boost and are cheap enough to not care so much when they go. Spin them fast or crank the boost past 20 and they are on borrowed time.
In reply to Paul_VR6 (Forum Supporter) :
Is there a line not to cross? 6 pounds 14, 19, 30?
What about temps? I'm going to have to put the turbo within 6 inches of the intake in order to fit it in that narrow compartment. I'll be relying on the alcohol to cool the intake charge, with maybe a burst of WW fluid at near peak boost.
In reply to frenchyd :
Tout = Tin + Tin x [-1+(Pout/Pin)0.263]
efficiency
https://www.gnttype.org/techarea/turbo/turboflow.html
This will tell you your temps after the turbo. Also, things like any bends or restrictions prior to the turbo will effectively shift your efficiency down and boost ratio up. You'll find that after about half a bar, the IATs get scary in a hurry, so you'll likely need far more than just alcohol for serious boost, but that also depends on your engine's knock sensitivity, your fuel, yada yada.
EDIT: Temp must be absolute, don't forget
In reply to cyow5 :
I believe you may be underestimating the cooling power of alcohol. Indy cars ran 60 pounds of boost and more when the turbo was pumped directly into the engine without any inter cooling. They did that at peak RPM for 500 miles. Stopping only to refuel and change tires. Normally the same engine used in practice and qualifying ran the race so more than 1000 miles would be on that before the race was over.
Now 85% alcohol vs 100% is some consideration but We are talking about 12 maybe 14 pounds instead of 60 pounds
In addition a typical race is maybe 40 to 60 miles instead of 500 Instead of foot flat to the floor the whole time the throttle is lifted for the 12-14 corners. At best it's flat about 80% of the time.
In reply to frenchyd :
no, I am underestimating YOUR engine, not Indy's ;)
Thanks to high cylinder speeds, knock is less of an issue for those motors unless you are planning the same redline, and their higher fuel flow rate also allows more cooling. At a lower fuel flow rate and at a lower rpm, the max tolerable IAT will be significantly lower. I believe you are also referring to the motors than ran DI injectors in the port plenum, so the delta P produced more cooling as well, compared to the same fuel flow rate with typical port injection pressure. I did this software for the Corvette team when they played with DI injectors in the plenum, but being N/A, they didn't see quite the benefit, of course.
Edit, did some digging and see that current Indy car is around 20lbs of boost so I am guessing you are talking about a much older era than I was thinking. I can't tell you anything about those cars or what tech they used etc. I hope you also got my well-intentioned humor in the above statements, but I want to back up and point out my original intent was to offer a tool to indicate IATs and not to tell you what IAT your engine can handle. As in this post as well as the first post, there are lots of varaibles, so I am just trying to offer one particular tool I have found useful
Well considering the Offy originated in the 30's by Miller as a cheap engine. The technology is pretty obsolete. The stroke on those in turbo form is similar to the stroke on a V12. And the bore is in the same neighborhood. The factory tested the V12 to 8300 RPM which is right up there with the OFfY
No they weren't direct injection. In fact the mechanical injection they used was developed by Hilborn in about 1948.
The nice thing about alcohol is how broad a mixture strength it works in. As long as the spark will ignite it alcohol will fire and make near peak power. So extra for cooling purposes was common. Those engines ran magneto's and put out about as much spark as the electronic ignition does.
To be fair the Foyt ( Bignotti ) V8 couldn't survive under the boost the Offy did which is why they gradually reduced the boost limit.
cyow5 said:In reply to frenchyd :
no, I am underestimating YOUR engine, not Indy's ;)
Thanks to high cylinder speeds, knock is less of an issue for those motors unless you are planning the same redline, and their higher fuel flow rate also allows more cooling. At a lower fuel flow rate and at a lower rpm, the max tolerable IAT will be significantly lower. I believe you are also referring to the motors than ran DI injectors in the port plenum, so the delta P produced more cooling as well, compared to the same fuel flow rate with typical port injection pressure. I did this software for the Corvette team when they played with DI injectors in the plenum, but being N/A, they didn't see quite the benefit, of course.
Edit, did some digging and see that current Indy car is around 20lbs of boost so I am guessing you are talking about a much older era than I was thinking. I can't tell you anything about those cars or what tech they used etc. I hope you also got my well-intentioned humor in the above statements, but I want to back up and point out my original intent was to offer a tool to indicate IATs and not to tell you what IAT your engine can handle. As in this post as well as the first post, there are lots of varaibles, so I am just trying to offer one particular tool I have found useful
Thank you, yes your comments are greatly appreciated. I've read countless manuals about turbo charging. But having never built a turbo charged engine* I really need guidance. I refuse to be the ignorant know it all and make stupid mistakes. So please, if you see me heading in the wrong direction, you have my permission to smack me upside the head. Not you Stampie, you'd enjoy it too much ;-)
Yes I realize that in those days they used 100% methanol and today it's 100% ethanol. About 114 octane for ethanol and 116 octane for methanol.
* I did kludge one together for Chump car. With help, using a pair of used Saab T2 turbo's. Which is still running around here.
In reply to frenchyd :
Since I obviously know nothing of those engines, I am guessing - but they were probably massively overbuilt to also handle such boost and wouldn't need nearly that level today to achieve the same power. I wrote this then figured I could use google and yup, they really didn't make *that* much power for the size and definitely for the boost. One factor could be IATs that could broil, so adding boost was only marginally helpful but helpful nonetheless. I see also that the engines had oversized bearings and a monoblock construction. So yeah, I don't think that's a good reference point for how much boost is tolerable unless your engine can also be similarly overbuilt.
Three inch mains, 2.3 rods. Crank is forged EN 40 steel and hardened post machining. Weighs 78.7 pounds. 4 bolt mains. Rods are the same. 6 .18 long. ( on a 2.75 stroke). Rod bolts look like ARP designed them. Heron head so combustion chamber ( Hemi ) is in the piston.
Plus I can buy them for slightly over scrap metal prices. 680 pounds of mixed metals is about $80-$100 if you pull them apart the aluminum will get you $300 last I checked.
TheV8Kid said:In reply to frenchyd :
We have a pair of these on the Nova. It has a 6.0L. they work great. Makes about 900whp. From the time you foot hits the floor to 18 psi is like half a second
How do you pick one out of the seemingly identical 8 or so gt3582's?
In reply to bluej (Forum Supporter) :
Given the success they've had I for one am perfectly willing to follow the leader.
TheV8Kid said:In reply to frenchyd :
We have a pair of these on the Nova. It has a 6.0L. they work great. Makes about 900whp. From the time you foot hits the floor to 18 psi is like half a second
Noted.
Any information on the rest of the setup?
frenchyd said:In reply to Paul_VR6 (Forum Supporter) :
Is there a line not to cross? 6 pounds 14, 19, 30?
I have some cheapass customers running them on 2.8l 6cyls in the low 20s they seem to pop around 25. I recommend upgrading to Precision, Garret GTX or other name brand turbos at that point.
Since I'm a road racer rather than a drag racer I'll be more conservative. Work up gradually to maybe 16 Pounds. And then only in passing or other shorter term event. I won't worry about the engine if I get the mixture right, but at that price it might be worth while to bring a spare.
Garrett has good resources too:
https://www.garrettmotion.com/racing-and-performance/choosing-a-turbocharger/
Heres another good resource, turbocharging handbook pdf
When you're designing a turbocharged system, you need to have some clear definitions:
Thats a pretty simple list but you really can't go anywhere without some of those decisions.
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