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Aluminum Head? or Original?

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BlueMax said:
Are we talking about WHP? Or BHP here?
Click to expand...

Alan, flywheel HP, meaning engine dyno, not chassis dyno. A few years ago, David Anton did a no holes barred 1380cc engine for the Classic Motorsport magazine project car " The Modern Midget " . Anyway it was very similar to your engine, almost to a tee, minus the billet crank and I beam rods which add no HP, it was almost the same, same cam, ported head, a little over 10 to 1 CR, almost identical to what you have built, he even had the DCOE on it, it netted 105 HP on David's Land and Sea engine dyno. I thinks that about the ceiling for a A series engine that is streetable on carbs.

We were able to get about 100 rwhp on Dick SCCA LP 1275 engine, which in almost all ways, via the SCCA LP engine rules was inferior to David's 1380cc engine, (SCCA LP rules allow no head porting, max valve lift of .450", stock rocker arms and stock HS2 carbs) except for CR, we are allowed to run 11.0 to 1 on the LP race engines, I think the higher CR was the only reason we were able to make more HP than a trick 1380, and if one could sneak the CR up a bit on the street, you could see a improvement on the strret engine, but fuel becomes a issue then, this may be a reason enough to try a aluminum head so you could run a higher CR, but thats can be dangerous and expensive game to play on the street, if you go too much on CR, then you doomed to octane boosters, race gas or getting another head.

These siamese engines love compression ratio, is by far the easiest way to mke HP, but we limited by the fuel we have for the street. The main reason we can get 140hp out of full tilt SCCA or vintage race engine is the CRs we were using, and the race gas we use, I've ran 1275 race engine as high as 15.5 to 1.

Alan, you could pump her up to about 12 to 1, and then run $10 dollar a gallon race fuel, it would be like you are paying Euro gas prices :jester:
 
Hap,
As you know in this business patronizing someone ego on how much hp that their engine can produce can be distorted base on the quality of equipment that is utilized as well the operator experience. As you have done many times in tweaking a customers engines with timing and F/R that you can pick up 5 to 10 extra HP. You can easily say that you will find 10 to 15 percent variables just in these two variables alone. Now if someone had some very deep pockets and wanted to build a half dozen engines built on all of the options plus a few more then run them on Cosworth dyno in Northampton where they dyno the F-1 engines. Or say run them on Jack Roushs dyno. I would think that you would have the best overall true Idea of what a racing engine builder capability with HP. In my view I don’t think that Vizard really had a firm grip on what he has written in his book on the HP charts because he was jumping around with dynos. You really can’t articulate with any wisdom of accurate HP unless you stay with the same equipment.. Also with each dyno run the fuel would be tested in a GC for any variables in octane so that you would know that fuel octane hasn’t distorted your testing too. Then I would say that the margin of error for calculating HP would be in the tenths of a percent.

I would say that David Anton would be as close to anyone with minimal amount of error here in the USA since he also grinds his on cams and he has his own in house dyno. But frankly for me if the car moves fast enough to scare the Sxxt out of me then that’s enough HP for me.
 
Regarding the Xflow head, if you have a crankfire ignition, like I do, there is not much downside to putting the carbs on the righthand side of the car and a lot of upside. Since I have no distributor and a remote oil filter, only the dipstick would be blocked from easy access. It sure would be nice to get the carbs away from the headers and it would free up a lot more room for the drivers footwell and the pedals and hydraulics. In a RHD car it does not matter, but when you try to put feet, pedals, exhaust and induction all in the same place as in a LHD car.......... Anyway I would love to have an alloy Xflow head, 5 or 7 port, either would be an improvement in my case.
 
Also... if anyone would like to see a crossflow head coupled to a turbocharger I'd be happy to install one in my car (if someone would like to send me a crossflow head free of charge). :smile:
 
BlueMax said:
Hap,
As you know in this business patronizing someone ego on how much hp that their engine can produce can be distorted base on the quality of equipment that is utilized as well the operator experience. As you have done many times in tweaking a customers engines with timing and F/R that you can pick up 5 to 10 extra HP. You can easily say that you will find 10 to 15 percent variables just in these two variables alone. Now if someone had some very deep pockets and wanted to build a half dozen engines built on all of the options plus a few more then run them on Cosworth dyno in Northampton where they dyno the F-1 engines. Or say run them on Jack Roushs dyno. I would think that you would have the best overall true Idea of what a racing engine builder capability with HP. In my view I don’t think that Vizard really had a firm grip on what he has written in his book on the HP charts because he was jumping around with dynos. You really can’t articulate with any wisdom of accurate HP unless you stay with the same equipment.. Also with each dyno run the fuel would be tested in a GC for any variables in octane so that you would know that fuel octane hasn’t distorted your testing too. Then I would say that the margin of error for calculating HP would be in the tenths of a percent.

I would say that David Anton would be as close to anyone with minimal amount of error here in the USA since he also grinds his on cams and he has his own in house dyno. But frankly for me if the car moves fast enough to scare the Sxxt out of me then that’s enough HP for me.
Click to expand...


Yeppers to all of that. There was Midget owner on another forum who used to talk about his carbed 1380cc making 125 HP, it just insn't possible, sure you could get there with frced induction, but with carbs no way. Also when it comes to dyno, they should be looked at as tuning tools more than HP rating machines, you tunthe engine on the engine or chassis dyno to be the best it ca ben and whatever the HP readings are, are what they are. Also one dyno to the next can read higher or lower, so you could have gotten reading on david engine as hig as 110 or 95 for example, every dyno reads a bit different and some comuter set up have different conversion charts to make it look more impressive as well. david uses the same set up i wans one working on, Land and Sea, in fact I horsed traded David my A series Land and Sea engine adapter for some parts, we put alot of work into that piece and it was nice unit, so I'm lgad David is putting it to good use.

HP numbers are great, but you're right people can become obcessed with them, just go out there and enjoy the cars that is the main thing. Also one should remember a chassis dyno will delute flywheel HP as much as 25%, so 75hp on a chassis dyno can easily be 90-95 for example on a flywheel dyno.
 
Ok then Hap the only thing I haven't heard in the equation is the gas required (octane?) with lets say a stage II set up. knocking etc... We all have to deal with what's available on the corner gas station.
 
Heh, not really. Fuel at the Marina is good stuff as well as that track side.
 
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