I was talking to R&D today and I am going to send them my motor to rebuild and stroke for me. They are going to build it as a 2.5 turbo motor, and they are going to dyno tune it and throw in an AEM engine management system. No word yet on the price but I know it will be over $9,000. Just figured I'd let you guys know that soon I will have one of the fastest Preludes around!!
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Originally posted by Donny_UGA I just wish I wasn't worried about the airbag. however if i wreck bad enough to need it. I probably deserved it.
2.5L would be nice, but what size bore are you going to use and what r/s length and ratio do you plan to hit? Since with the H22, the r/s ratio is not the best for high revving, so you may have to lower your max revs if you're trying to increase the displacement a lot. What's included in the $9k? Since the turbo + engine management alone will cost you about $5-6k w/o labor and then there's tuning. If it's a full engine rebuild it sounds like a pretty good price, hefty, but good.
I would highly advise getting some kind of warranty with that... or buy a backup motor. A turbo is enough trouble alone, let alone a completely-redesigned bottom end... stroked no less.
Let's see... add the two most difficult things you could do with a Prelude motor... stir it up in a pot... what do you get?
go for it.. but i thought r&d dosnt stroke to 2.5 when using turbo.. becuase of the lack of space between the cyl walls.. or was that they dont do the 2.6.. ahh well good luck..
I am not sure about all of the ratios and whatnot but I will be giving the final sayso after I see all of the specs of the motor. The actual motor alone is going to cost $7,800 and the AEM engine management is going to be $1,800 and change so there is $9,600 right there. Then the turbo system will be about $4,000 and then they are going to tune it for street driving for me on pump gas and then also have another program tuned for the track! So I don't know how much the dyno tuning is going to be. I will probably be shipping out the motor to them in about 2 months, once I buy the turbo components and all. I will definitely keep you guys informed on when I send it out and also about the progress and on the final numbers!! DeAngelo said about 450-500hp to the ground!! We'll see what happens!!
BTW, he also told me that he had just built another turbo motor that was putting out 637whp!!!!!!! That is crazy!!!!
Also, they won't stroke to 2.6 because the walls are to thin but 2.5 should be OK. If not, I will keep it down to a 2.4, but that is the absolute lowest I will go!!
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Originally posted by Donny_UGA I just wish I wasn't worried about the airbag. however if i wreck bad enough to need it. I probably deserved it.
Originally posted by marcucci I would highly advise getting some kind of warranty with that... or buy a backup motor. A turbo is enough trouble alone, let alone a completely-redesigned bottom end... stroked no less.
Let's see... add the two most difficult things you could do with a Prelude motor... stir it up in a pot... what do you get?
All I can say is, GOOD LUCK.
I can attest to that...turboing a 2.2l is hard enough...2.5? if you can pull it off, then congratulations, but if you dont..youre wasting ALOT of money...talk to akira on the boards..hes got a setup that is looking to make some serious power..
dude did you think about building a bullet proof bottom end.. i mean serious **** godzilla sleeves, forged pistons, etc.. and the money on the aem.. you the right setup you could spend 5-6k
and make 400whp
which is really really almost too much for the street..**** the storking now that i think about it hhehehe.. j/k
2.5 liters? Well, let's see what that gets you; displacement = (bore/2)^2 * 3.14 * stroke * 4. Do all the measurements in cm so that the displacement comes out in cubic centimeters.
If you use the stock bore, 87mm, you would have to increase the stroke to about 105mm.
The Prelude comes stock with a 90.7mm stroke and 143mm rods for a rod ratio of 1.58 (rounding). That's the longest rod you can use with a 90.7mm crank without going with some custom pistons and rods. You can move the ring pack up some, and compress it, however you're going turbo, so that's a big no-no. So, we are going to assume that's the longest rod you can stuff in there with a 90.7mm stroke.
Now that you're increasing stroke to 105mm, you're going to have to shorten the rod to 135.85mm. That yields a rod ratio of 1.29!!!
That low rod ratio combined with such a long stroke is going to yield some seriously high piston acceleration and mean velocity numbers, not to mention the side loading. I sure hope you don't plan on using the stock rev limit, because the engine probably won't run that high without some problems (not to mention the engine is going to suck on the head a lot more, so headwork will be needed to flow more air into the engine).
So, now let's say you can bore the engine over to 90mm (that's about the max, even with sleeves). That's going to require some massive sleeves, and you're going to invade the cooling jacket quite a bit. Not to mention, that's 3mm less between cylinders, so high boost could be a problem. So, if you increase bore to 90mm, the stock stroke will get you to 2307cc, or 2.3 liters. Not quite there. You're going to have to increase the stroke still. Now, the stroke needs to be 98.3mm. That means that the rods need have a center to center length of 139.2mm. That yields a rod ratio of 1.42. Still not very good.
I am not saying it can't be done. I have seen an H23/H22 head engine run up to 8k rpms, and the H23 has a rod ratio of 1.49. Of course, this H23 put a 5" hole in the block, but that doesn't mean anything.
With a larger bore and turbo, I would suspect that cooling is going to have to be addressed. Piston squirters won't fit with a stroked crank, and sleeves might compromise the water jacket, so be very careful.
Also with a project like this, headwork and intake manifold work are mandatory. The lower the rod ratio and larger the stroke, the harder the bottom end is going to suck on the head (at a given RPM) so the intake tract needs to be able to support it.
You have a huge project ahead of you, regardless of who does the work. I would suggest that you educate yourself (this isn't a flame) before you go and make serious decisions like this. From what I can see, and engine like this (unless R&D has some sort of trick up their sleeves) is going to be running on the ragged edge. Tuning is the key, if the tuning is off, you're going to break something, and perhaps ruin the engine. RPMs are also the key. This thing isn't going to rev to 8k or even 7k RPMs safely. If you beef up the components to handle the lower rod ratio, you're going to get a lot of wear on the cylinder walls from the side loading, not to mention beefier pistons weigh more, which is going to cause the engine to rev slower and it won't want to run as high.
A solution to all of this could be a custom block extension. This would be a major project, though. Custom sleeves would need to be made, then a block extension welded to the block. A custom timing belt would also need to be sourced. Since the engine would be taller, hood clearance would be an issue. This would allow a longer rod to be stuffed into the engine so that the rod ratio can be brought up closer to the ideal 1.75.
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Billy - 98 Prelude
#27 H2 NASA TX HondaChallenge
#27 PTB NASA TX Performance Touring Racing makes heroin addiction seem like a vague wish for something salty. -- Peter Egan
One other thing, I assume they are planning to weld and regrind your crank, as there's not enough material to grind off the stock journals, and it doesn't sound like you're going for a custom crank ($3500+). So keep in mind a welded crank is not as strong as a custom crank or stock crank as the welding and grinding procedure weakens the crank. If you're going for ultra high HP, this could pose to be an issue.
Does $9k cover fuel, intake, engine, cooling, etc? If so, it's a good deal. I would expect to pay $9k for the engine alone, if not more.
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Billy - 98 Prelude
#27 H2 NASA TX HondaChallenge
#27 PTB NASA TX Performance Touring Racing makes heroin addiction seem like a vague wish for something salty. -- Peter Egan
Originally posted by OutlawLude Something I forgot:
I better get a damn warranty if I am going to spend like $10,000 just for the motor and their work!!!
Warranty....bwahahahahahaha!
Oops, sorry for laughing.
My opinion, if you don't want to throw away $10K+ dollars don't do it, if you don't mind, then go for it.
Getting a warranty on a motor with the specs your calling for is a tall order.
Also, the life expectancy of a motor like that is counted in months at best.
Just my opinion.
I also hope you don't plan on trying to drive this on the street as a daily driver. Driving this daily would shorten its life expectancy from months to weeks.
I am not flaming, just stating my opinion. I also think the costs will add up to way over $10K for a motor like that.
If you do decide to take this route, I will be very interested in watching the project. While I am a pessimistic about such a venture, I am intrigued as well.
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2007 350Z (San Marino Blue)
Best 1/4 so far, 13.198, best trap 107.19. *stock*
2002 I35 Sport *stock*
2005 Armada SE *stock*
did you guys read the scc article comparing r&d engines to aebs engines? billy r&d does much more that what you listed as a way to achieve their larger displacement numbers.. they offer mild setups that garner 220 whp.. as for the 90mm bore.. honda even offers a 90mm bore for stock pistons, rod ratio is not the sole determining factor for piston acceleration either, the 1.75 magic rod ratio is not always the most ideal ratio when it concerns pistons acceleration or side loading.. just a thought, i doubt r&d will take that much money from a customer and give them a hunk of garbage back.. its just not going to happen.. they have a great reputation.. were you not yourself planning on spending that much for you build up with Larry? i think the 2.5l motor and boost is an extreme project.. but he is willing to pay extreme money.. r&d also makes stroker motors for sohc 1.6's to 2.0! and yes i have these motors on the street, they are quite the sleeper.
Please provide a part number for a Honda H22 90mm piston. I have never seen it. The oversize pistons are only 0.25mm oversized (or is it 0.5mm, I can't remember).
As for their reputation, I know nothing of it, just what I have learned from experience and others that are more knowledgeable than I am. If Honda told me that they could make a 2 liter VTEC engine that could spin 30,000 RPMs, I wouldn't believe them, regardless of their reputation for building good engines.
As for piston acceleration and mean speed at a given RPM, rod ratio and stroke are the only determining factors that I know of. Please shed more light on your statement.
As for a 1.75 rod ratio, it's not always ideal, but it is generally accepted that lowering the rod ratio is usually not a good idea. The rod ratio is a good factor in determining side load, as the lower the ratio the more severe the rod angle is. What other factors do you know of that affect side loading aside from cylinder pressure?
I was planning on spending quite a bit with Larry on my buildup, but I had realistic goals in mind. We were going to move the ring pack up and compress it a bit to lengthen the rod and improve the rod ratio to 1.62. That's about all that can be done without some extreme measures like single ring pistons, destroking the crank, etc. I also wasn't looking to boost or rev very high. The engine was going to be NA with stock sleeves, stock size pistons, and the highest it would rev would have been about 8k RPMs.
So, if you think I am being critical of his ideas, you should re-read my post. I am not trying to flame him, but I am trying to tell him that he should try to be a little bit more educated so that he can understand exactly what he is getting into. If you feel the need to criticize me and the things that I have said, please offer more insight into your arguments. e.g. rod ratio not being the sole determining factor for piston acceleration. Please provide more details so that perhaps both of us could learn something.
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Billy - 98 Prelude
#27 H2 NASA TX HondaChallenge
#27 PTB NASA TX Performance Touring Racing makes heroin addiction seem like a vague wish for something salty. -- Peter Egan
I have that SCC article with me right now and the engine in that article is 2600cc and it's putting 260HP at 8800RPM with over 200lb-ft of torque. they say that they can detune that engine for pump gas and lower rpm driving and still put out 220WHP and 180lb-ft. they also recommend keeping the engine below 2400cc for heavy nos or turbo
if somebody want the whole article I can scan it for you
I assume it's an H22 right? I think I let my subscription run out...what month is the article in?
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Billy - 98 Prelude
#27 H2 NASA TX HondaChallenge
#27 PTB NASA TX Performance Touring Racing makes heroin addiction seem like a vague wish for something salty. -- Peter Egan
I was under the impression that rod ratios are more of a theoretical figure since there isn't really an ideal rod ratio for any car, stock or not? Rod ratio (what I learned) is when you divide the length of the connecting rod by the total length of the crank stroke (2x the radius). Most stock ratios are around 1.615 or so.
I don't think that there is an ideal rod ratio that includes ALL cars, it comes down to an ideal rod ratio to suit the displacement/intake length/cam profile of a certain engine. All of them must be acting together to get the most efficient breathing.
If the rod is lengthened, the piston will stay longer around the top center. Errr...or the piston will stay at the top of its stroke for a slightly longer period of time while the rod/crank is moving through the uppermost position (TDC? or something). In turn, the rod WILL effect piston acceleration. If the rod is made short (which has to happen with OutLaw's setup), it will cause the piston to accelerate much quicker. Now I think this would actually hinder the horsepower to be made. If you balanced the rod ratio and intake length, it would make much better gains.
When compression ratio and a cam is being considered, the rod is shorter, and relatively the cam displacement angle can be stretched out and the engine compression ratio can be increased, since the piston will stay at the top of the block for a shorter period with a shorter rod the cam angle is less restricted(??)
I think your problem would be when the piston is traveling up at high velocities, with no compression up-top, and when the rod tries to slow the piston as it nears TDC, the rod can go, and the piston can go.
REGARDLESS of rod ratio, the greater the RPM (which has to happen in his setup), the higher velocities. That is where you will run into problems and I think that is what Billy is trying to say.
1.75/1 would be the ideal rod ratio. If you lengthen the rod relative to the crank and the ratio grows larger, the wear goes down and so does the piston speed, but this will contribute to an engine having a very narrow useful torque range. I was under the impression that all Hondas have low ratios to begin with. The short rod allows a short block.
Billy or someone? Wouldn't increasing the ratio make the combustion region smaller? That would able to accept more of the crankshafts rotation. THAT right there would decrease the chances of detonation and increase cylinder pressures (a good thing).
It might work. With the right amount of money and motors (plural) I think you can do anything...
Originally posted by Forbidden yes it's an H22, it's in the August 2001 page 164
I bet they don't say anything about the durability of the engine, right?
hehe, it wouldn't be extremely difficult to make a 300 HP NA motor if you weren't worried about the motor lasting more than a race or two.
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Billy - 98 Prelude
#27 H2 NASA TX HondaChallenge
#27 PTB NASA TX Performance Touring Racing makes heroin addiction seem like a vague wish for something salty. -- Peter Egan
Of course when you raise RPMs, you raise piston acceleration and mean velocity, that's obvious.
If the rod is lengthened, it does affect piston acceleration, however;
longer rod = higher rod ratio = lower piston acceleration
That's what I was trying to say, or at least, part of what I was trying to say.
Okay, first off, I suppose I need to step back and say a few things. ANY ENGINE is a series of COMPROMISES. There is no "best" anything for all applications. That being said, I shouldn't have said that 1.75 is an "ideal" rod ratio, but it is thought to be ideal for most applications. Smokey Yunnik (spelling?) actually recommended rod ratios of 2+ on his race engines.
A longer rod allows the piston to dwell at TDC and BDC for more degrees of crank rotation. This does allow the combustion pressure to exert more force on the piston, hence more torque.
If the piston acceleration is extremely high, theoretically the piston could outrun the combustion "shockwave." I haven't heard of this happening, but theoretically it could.
Another consideration with extremely high piston acceleration figures is ring flutter. Again, I haven't actually heard of anyone that had this problem, but then again, I haven't known anyone that built an engine with a 1.4 rod ratio.
The rod ratio is by no means and end all, but it is an important consideration when building a high performance engine. The "ideal" engine would be one with a large bore, small stroke, and good rod ratio. All of which, the H22 possess NONE.
Now, that being said, everything has to work together in order for any of this to work. i.e. the headwork needs to match the bottom end, the intake needs to match the head, etc. etc.
As for compression ratio, there are a lot of considerations, especially when dealing with dynamic compression ratio. One must take into account timing, cam timing, cam profiles, etc. etc. So, I don't think you can really characterize CR by saying that with a shorter rod a higher CR can be run (if that's what you're trying to say).
Damn, this is turning into a damn good thread.
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Billy - 98 Prelude
#27 H2 NASA TX HondaChallenge
#27 PTB NASA TX Performance Touring Racing makes heroin addiction seem like a vague wish for something salty. -- Peter Egan
no they didn't say anything about durability. AEBS on the other hand said that their engine ran the entire 2000 season without any trouble but I don't think there's been a mention about durability in the R&D part of the article
I will probably be shipping out the motor to them in about 2 months, once I buy the turbo components and all. I will definitely keep you guys informed on when I send it out and also about the progress and on the final numbers!! DeAngelo said about 450-500hp to the ground!! We'll see what happens!!
