You'll be lucky to make 175HP with that engine - depending. Like I said, I'd be lucky to make 200hp. Especially knowing that Jerry's engine made 240hp from Motor City with a blower on it. Mine's an old dirt track engine with an Isky 400jr in it, it should sound really good anyway. Love that flatty sound. Kevin Ooltewah Speed Shop
just food for thought ... there are turbo Suzuki Hyabusa's running on the street that make 600 HP on racing gas ... Joe
Maybe you could. Some have tried but with the already restricted exhaust ports and the rate of heat transfer into the water jackets with the restricted exhaust ports. Putting a turbo on it causes the heat transfer to go off the scale and so much energy has been lost to the water jacket by the time the exhaust gets to the turbin it just hasn't worked as well as crank driven blowers. That I have seen anyway. Your results may vary.
I agree - not the best motor design to go turbo on --- the exhaust has enough issues as it is. Direct drive baby . . . roots, paxton, or something like a pro charger . . . nothing like the sound of a blown flatty with uncorked exhaust!
I've also personally met Joe Abbin and seen his work. I just bought his new book too. This fella knows his business and I would put money on him getting 300+ hp out of what he makes. Read up on his stuff at roadrunner engineering before you start thinking he's blowing smoke about the numbers. I really don't think there are more than maybe 5 people on the planet that know as much about flatheads and Joe is in that group.
Since I'm not planning on getting much, if any, more than 300 (if I'm lucky), I'll just use steel mains. There's a few 300HP engines out there with just a steel center main. I agree - I think 300 is one threshold. Beyond that, it's exponentially more difficult to squeeze any more out. Not that you can't, you certainly can, but the expenditure required goes off the chart. There are lots of myths out there. Joe does a good job debunking many of them in his books. These guys answered ya: I have a huge amount of respect for anyone that continues to work on these engines trying to improve the breed. It's folks like Joe, John Lawson, and others who use empirical data to show what works and what doesn't. Joe is one of the few who goes the next step - racing to validate the dyno ('cause we don't race dynos & flow benches!). The blower really wakes up the flatty due to the restrictive breathing of the design and it's emminently streetable too, for the most part.
I think the roots approach is inherently better here...turbos put out boost at high RPM/wide open conditions, while a big roots can pack the engine full through much of its range. Making your power throughout a fairly low band is good on normal type engines because RPM stresses the parts, especially rods, much more than even blower assisted power ever will. The highest loads on rods are on EXHAUST stroke, nor power, because of the unresisted outward throw! The only blown flathead I have driven was Flatdog's 12 second coupe; that thing seemed to have a big block power curve from right off idle to 5,000, there didn't seem to be any curve in the power curve...
if you want turbo a flatty go for a better designed one, no offense guys, but 3-mains, and a rediculous exhaust idea, not good for turbos anyway, as was stated. do like a hudson or dodge 6, i always thought a turbo 308 hudson would be cool as hell....
Well, things have changed but I saw 235 on the dyno at Paul Schiefer 276 engine on Alcohol. and that had everything done to it. Only think left would be nitro and blower. Paul had the dyno vented to roof through a 6 inch pipe to a 55 gallon drum on the top of the roof. when he ran the first pull on the engine it burnt the paint off of the drum on the roof. Surprised me! traderjack
I think the word "blown" says a lot. We have worked our asses off to get 181 hp out of one engine for our Bonneville truck, but we now have a new engine that we are praying for 200 hp. 200hp will put us where we want to be in our class. More infor about our dyno days and pictures etc at www.gasolinealleyshops.org Steve down the street at Un Common Enginering builds 300 hp dyno tested blown flatheads and they seem to have some street life in them as well. His web site shows his blown stuff as well..
There are quite a few of in "Flathead Land" that are trying for that magic 300HP number. When I get the motor back from my machinest I hope to prove all my blood/sweat/tears/money can prove this or Flat Ernie says, "Get real close". I will be shooting for 6/8 psi and I'm hoping it will be as reliable as any HP street motor. After this I plan on building another flathead with just a little more HP than this one, and already have most of the parts except the pistons. As for cost, with the money I have spent todate, I could have gone out and bought a 550/650hp crate motor. Here are some of the parts I think are neccessary to make a reliable 300hp flathead;
Nice parts. The oilpan must be a headach to make with the girdle. How come the girdle doesnt connect the front and rear mains.
there's lots of meat at the front/rear of the block. It's the center main that really needs extra support once you move past the 300 or 350hp/tq range. I can't recall for sure but that particular girdle and custom pan is like ~2k ------- One of the neat things about Joe's new book is that he literally spells out in black and white how each build was done and how to easily repeat the build for yourself. In the case of Boomers engine, It made over 300 blown (315? -memory) and over 200 naturally aspirated. I am running ~7lb pulleys which is a little more boost than what was used to turn Boomers engine to 300+hp but other than that the build will be very similiar. (I just dropped a block of at the machinists) I think Abbin's new book can be considered ground breaking in the simple-easy to follow way he lays out how you can build a ~325 blown or ~225 naturally aspirated Flathead with just 276ci. Well worth the $$ .
just think how many flatheads were blown to smithereens to come up with all the technology nessessary to pull that off. you got to be a little nutty to to go to all that trouble for so few horsepower. good nutty, not bad nutty.
In much the same way that a lot of gearheads believe that they have to run the exotic parts to make the HP, Joes book makes it clear that such an avenue isnt required. In fact, its interesting to see how basic/non exotic his combos really are. What his engines do feature is attention to detail. Esp in the cyl heads, machining, clearancing, intake/exhaust porting, headers and timing control. And critical evaluation with hours of dyno flogging backed by TRACK RUNS to verufy weight shifted HP/TQ. This for me is the clincher. Its interesting to note that most of his engines run the 400Jnr - traditionally a cam with mild duration @ .050" and .400" (less lash) of lift to aid in the breathing dept. These cams are far from radical cams and in a blown combo, the blower tames them down considerably, while the lift feeds the heads and mild overlap prevents boost going out the exhaust. The 400 Jnr is not a custom ground "blower cam" None of his engines run a girdle and run hard and well; most with prepped Ford cranks as well. This goes for the rods as well, although he has used Scat rods too. They run a 1" strap on the centre cap, much like the way I did my blower engine. Note that they ALL run a Holley 570 with the blower to make the HP/TQ. Fuel atomisation and throttle respose (not to mention tuning ease) on a dialled in Holley would be light years ahead of the crappy 97s/94s that are commonly used. Not traditional but hey, its works hehe. I also noted that the 300+ HP runs were made with 106 Octane race gas - perhaps for a margin of safety at 7-8 lbs of boost. Hey no problem there, add thepulley/ fuel when you hit the track and go and have some fun. Remember the old guys ran NITRO Flatheads with mostly stock parts and broke records. Sure, they broke engines too, but this is why modern tech helps prevent this with timing control, forged pistons, rods etc.... If I wasnt in the middle of a Hemi project, Id LOVE to build and identical clone of Joes EAC Merc headed engine to keep the price down and add the 4-71 to it then dyno to see what she will do. Identically means porting, head mods, cam spex, dialled in the same way, CR etc....hmmm, have those forged Ross slugs lying around hahaha. Yes some dynos are happy and everyone needs to sell, but the car has run the numbers via weight shifted HP at the track so that makes me a believer. And no I dont know Joe at all. Rat
yea, but... it aint how fast you go, its how you go fast building a "high" HP flat motor is not a work in speed and performance... its a work of love, dedication and desire to be completely period perfect, cause face it... no one is reinventing the wheel when it comes to performance flattys
So, I have both of Joe Abbin's books and I can't quite figure something out. He has a chart for expected HP for a 276 cu in engine based off of compression ratio, boost and the octane gas used. Could someone who has the book tell me how to read the chart. I thought I had it figured out, but then the more I look at it the less sence it makes to me... thanks, Todd
I'll be honest, I looked at his charts for about 5 minutes, then my eyes glazed over and it was the next day....
All my books are packed away and floating on a boat somewhere most likely....just moved back to the UK, so access is limited. I saw Boomer's engine make 305HP - I was there. It was pretty incredible. Joe's engines are not exotic, but they are detailed. He's spent years researching flow. I've seen his head book - loads of heads each with pages of info on them. Surprisingly (or maybe not), there really isn't loads of difference between most of the heads out there from a flow perspective. I think Joe settled on using Offys simply because they're readily available and have thick chambers for the work he does. If you enjoyed his first book, but haven't bought his second one yet, it's well worth it! It's available on his website - google roadrunner engineering and you'll find it.
First thing I look for in charts: 1. If the HP for 15 psi is double the HP for 7.5 psi etc. (boost directly proportionate to power), or 2. Power is directly proportionate to boost ÷ atmospheric pressure (such as 14.7 psi = double the power), then ... he's pulling numbers out of his ass.
Hey Panic; The volumetric efficency of an internal combustion motor is not 100%, if it were you would be correct. I could forward you some nice reading on superchargers and how they work.
Ive heard some pretty wild flatheads, problably close to the 220 n/a. I remeber seeing the flatfire car. It had a redicules hp # was the rumor(dont want to missqoute the #) one of DLE deals. It set a record that much I do know.
HUH? Im as cynical as the next bloke but how do you argue against weight shifted HP/TQ at the track? On video no less? Man Im a doubting Thomas but hey, it runs the numbers and you dont race theory, you race cars. We've all seen combos that should'nt run hard but run very heard and fast they do. Pls explain what you mean by your comment ? Rat
Landy did that engine for Ron Main, and it cranked out over 700 HP. It ran 300 and some change at Bonneville in the Flatfire ' liner. Mucho big bucks! I would say that this is the pinnacle of any Flathead ever built, and is truly awesome....
Mine looks very similar to those and ranges between 83-87h.p. depending on how clean the car is !! (I want one)
Quote" Yes some dynos are happy and everyone needs to sell, but the car has run the numbers via weight shifted HP at the track so that makes me a believer." Yes, if you have the dyno sheets and the timing tags, you have been there and done it. There were a lot of us that could get over one hp per cubic inch NA in the old days and drive them on the street. And yes, I have been told by the experts and big names that I am full of shit but when I look at the timing tags on the wall, I just chuckle.
Theres a lot of talk regarding the three mains and the use of the main girdle. Anyone got some pics of one broke ?? I have never seen a pic with the main cap blown out, got to be a terrible mess..???.
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