johnc Posted August 23, 2002 Share Posted August 23, 2002 > Personally, I would rather be able to say my > car is fast and I built the motor instead of > saying, Hey I paid Sunbelt 10 grand to build me > a 300 hp NA engine. No personal attack assumed, but I've had a few people privately tell me the same thing some I guess its time to defend myself a little. I'm a chassis/suspension guy. I would much rather disassemble a shock and try different valving then take an engine apart. I've rebuilt and modified about a dozen engines over the years but I just get more excited about what's involved in suspension and chassis setup. To me an engine is just big heavy a lump that gets the way of good suspension design. They never make engough power and what little power they make is always at the wrong rpm. Plus, they are tempermental and require a lot of attention. If I have the money I would much rather pay someone to build me an engine to my horsepower specs and provide a warranty on their work. Luckily, for the first time in my life, I had (notice the past tense here) the money! Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 23, 2002 Share Posted August 23, 2002 No attack assuemed either, hope you feel the same way. I was never looking to change anyones mind nor convince you that you were wrong, (because I happen to agree with you on most all your points). My "higher level" is quite simple, (well, from my point of view anyways ). It is not new and is borne from having a webpage on the net that far too many people took as gospel. When I first wrote it, I didn't understand how people on the internet interpreted webpages/info on the net. My credentials were solid enough that people assumed what I wrote was 100% correct, and for mulitple applications at that! Over time, I saw that since I chose to put that information out for people to research with, I had a responsibility to ensure it was correct and was backed up by facts. I am still working to improve those things. You can read my page now and still find hearsays, ambiguities and such. Over time I hope to eliminate all of them. I guess I have been spoiled with sites like corner-carvers.com. When someone comes asking about a cylinder head, suspension parts, etc.. for xx platform, you must back up your claims in your suggestions. Otherwise you had to qualify your answer. You were doing just that, but in a way which left much to be questioned,(ambiguity, vauge). The reason I chose your post was I knew you would have the real data to back it up. I would not have picked on someone with 10 posts who was a relative unknown. Sorry to call you out in that way. I did get carried away when I did it to yo2001 as well. Sorry. And thank you for the details on that motor. That adds so much more to the discussion, and lends more credibility to your assertions. I realize most people don't care if people think their posts are "credible" but I do. Too many people bench race and napkin draw on the internet boards for the uneducated to sift through. For those who have actually built, driven and seen the numbers, (1/4 mi, flow charts, dyno figures), they have much more to share. I know by now you understand where I am coming from,(whether you agree or not). A few small notes. Yes, you said in your first post a car with a P-79 ran 8.40's,(an incredible time for any NA car - even if it did have 4.08's). But we had no way of knowing that was the same car refered to in the second post. It might be infered that with the shaving amount, but we had no way to know, hence my comments. And when you said I muddy's the waters to talk about realative skill at the track I think I was misinterpreted. I wasn't saying posting actual times are bad, but rather saying you beat XX on the street is bad. There are so many unknowns in that situation, and I see that as muddying the waters. If they suck at the track, it will show in their time. I gave the moron in Norm's car as an example relative to the street. I see how that is interpreted to mean talking about cars on the track. I mean talking about cars on the street. Something like saying, "Hey, I lined up against Norms' car,(a known sub 13 sec car), and beat it! What is not mentioned is someone else was driving it, and they didn't know what they were doing, and it wasn't at the track. Not clear, my fault. Not arguing, discussing. And the head setup thing, your right, its their problem. However, if they decide to shave a P series head 80 thou or 110 thou, they now need to know how to set their valvetrain up. It is only fair to warn them they will have to seek someone like you out to walk them through checking the setup of the wipe pattern, lash pads, etc.. Most people don't have that knowledge, that is why I tell people to shy away from it unless you know what you are doing. You know, so it is not a big deal. Most can learn very easy, but someone has to show them,(and warn them). Lastly, I agree 100% about building your own motor. However, Sunbelt has developed their new cam grinds, allowing huge cams with less than stock spring pressures. For that, I am willing to pay them to setup the head properly to work with their cam. I'm actually pretty excited, because I will switch to FI at the same time. But that is a next year project. -Bob Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 23, 2002 Share Posted August 23, 2002 Why call somebody out? Why not simply ask for more details and Breaking someone's post down into parts and responding to each section you have issue with is not going to make friends out of the people you are doing that to. Touche. First though, I wasn't calling you out. As I said before, if you took it that way, I'm sorry,(actually, it was some smart ass wheaties comment ). What I was doing was disputing/looking for more info on the facts. My method however, was most certainly unconventional. I have done the polite post part for a long time. And after several posts, it usually comes out that they know what they are talking about or are blowing smoke. Often, it ends up with confusing or conflicting info. Sometimes it takes something big,(oh, like me being a jackass) for people to change their ways,(talking the board in general). I knew before hand,(from watching you post), that you were not blowing smoke. Second, for me it was like playing devils advocate since I personally prefer the P series heads,(and that fact is fairly well known). And I have no problem disagreeing about the best head for minimal work. And AGAIN, I, nor anyone else, was trying or wants to convice you different. And noone here, me esp. considers you crazy for your P series ideas,(now that whole living in Alabama thing... ). I will take the above comments under consideration. But it is likely I will keep my approach. I still take issue with vauge and indefinite examples. People like John, Dan, Norm, TimZ, JeffP, yourself, and many others,(those were mainly L6 type folks), bring so much to the table with actual experience. And most of the time that is what I see. But as we stay on mailing lists and message boards for long times, our answers get shorter and shorter as the same questions are asked again and again. I can think of one person on the IZCC list who fits this bill very well. An amazing amount of knowledge, but usually responds in a sentance or two. It robs the reader of a good answer. I chose to be the one to bring it to everyones attention. You and I spared (sp?) over it, but in the end, all is ok. We need an icon for a dead horse. I rest, as I think we have beat it well. Datto, I'm sure we muddied the waters for you in the process. But between the P and N series, you can't really go wrong with your carbs. Big thing, pay someone to tune it properly, or as Lockjaw says, "it won't fall out of a tree" (BTW, hadn't heard that one before! ) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 23, 2002 Share Posted August 23, 2002 DATTOZG, Just put em on the car, The sound of those webbers sucking in air is worth the effort. Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 23, 2002 Share Posted August 23, 2002 Man, I suck, I always forget something and then have to go back and post again! Yo2001, I would love if you could scan the flow sheets. I have flow data from several people, and am trying to complie a list. If you don't want to post it somewhere or here, you are more than welcome to e-mail it to me. And I should clarify the 10 hp increase a little better. I said it was a compression game. Yes, but it is also switching to a flattop which changes the quench characteristics of the chamber. Pushing that burning mixture towads the center,(causing turbulence), as the piston approaches TDC is also helping gain some more power. And there is a caviot to my example,(which I so conveniently left out ). Bolting an N-42 to a flat top motor produces a CR near 10:1. That is the big reason why it will produce more power than a 8.6:1 motor, head nonwithstanding. Now, bump that P-79 up to the same CR, and it will produce more power. I was getting carried away when I responded. Guilty. -Bob Quote Link to comment Share on other sites More sharing options...
yo2001 Posted August 23, 2002 Share Posted August 23, 2002 Originally posted by Bob H:Man, I suck, I always forget something and then have to go back and post again! Yo2001, I would love if you could scan the flow sheets. I have flow data from several people, and am trying to complie a list. If you don't want to post it somewhere or here, you are more than welcome to e-mail it to me. And I should clarify the 10 hp increase a little better. I said it was a compression game. Yes, but it is also switching to a flattop which changes the quench characteristics of the chamber. Pushing that burning mixture towads the center,(causing turbulence), as the piston approaches TDC is also helping gain some more power. And there is a caviot to my example,(which I so conveniently left out ). Bolting an N-42 to a flat top motor produces a CR near 10:1. That is the big reason why it will produce more power than a 8.6:1 motor, head nonwithstanding. Now, bump that P-79 up to the same CR, and it will produce more power. I was getting carried away when I responded. Guilty. -Bob okay, I can scan you the flow sheets and email them to you. I would like to see what you got too. Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 23, 2002 Share Posted August 23, 2002 The only one I have immediately available is my own P-90A. I just moved and many things are still in boxes, or somewhere waiting to be discovered. It will take some searching. Actually, I'm gonna post asking for some more. There are a few of us out there that have our flow sheets from our heads, and that can add to what I have. -Bob Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 23, 2002 Share Posted August 23, 2002 To the guy with webers, get those babies on a head which gives your engine some compression and throw a cam in there and go. You will likely never hear a sound finer than sidedraft webers and a L series 6 with compression and a cam running thru the gears. I loved the sound of my webers when I ran them, and they were very responsive. If you need tuning help, let me know, I can get get you in the ballpark almost immediately, and it should only be a matter of some minor main jet/air corrector to make it spot on. Again, webers are not as bad as everybody thinks. If I could figure them out, anybody can. Quote Link to comment Share on other sites More sharing options...
pparaska Posted August 24, 2002 Share Posted August 24, 2002 Originally posted by Lockjaw:To the guy with webers, get those babies on a head which gives your engine some compression and throw a cam in there and go. You will likely never hear a sound finer than sidedraft webers and a L series 6 with compression and a cam running thru the gears. Man, you're not kidding. I was at Summit Point (East Coast US Road Race Track) a few years ago (spectating) for the York Z Convention track day. Hearing those triple weber cammed L6s at full song is beautiful music! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted August 24, 2002 Share Posted August 24, 2002 Hearing those triple weber cammed L6s at full song is beautiful music! Can't argue with that Quote Link to comment Share on other sites More sharing options...
Guest DATTO Posted August 24, 2002 Share Posted August 24, 2002 wow i didnt mean to cause this much trouble between people...i was just looking a for a quick opinion, i just want to have fun with my z,,,maybe ill try all configurations,,,why not,,,thats what my z was for...to have fun with...my setup is a 2.9L nismo dish piston block that was heat treated, knife edge crank, counter weighted, shot peened, and titanium sleeved with 100 over...well i had an E31 head with nismo valvetrain and a 280 dur mild cam and slightly ported and balanced and bluprinted...with that setup i got 200Hp at the wheels with SU's on the dyno...my friend who built it said it was ready for some triple carbs. i used to rev my car to 9k rpms with the SU's with no problem...so i was thinking toss some trips in and have fun...thats all...ill keep everyones info..ill prolly try all configurations and see which i like the best...thanks everyone for your input i appreciate it...take care and have a beer! Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted August 24, 2002 Share Posted August 24, 2002 Originally posted by Lockjaw:To the guy with webers, get those babies on a head which gives your engine some compression and throw a cam in there and go. You will likely never hear a sound finer than sidedraft webers and a L series 6 with compression and a cam running thru the gears. I loved the sound of my webers when I ran them, and they were very responsive. Wow! That is the truth - I fell in love with Zs when I heard that sound. It inspired me to buy one. Although I never got away from the FI, and then went turbo, I still hear that sound in the L6, even if it is muted a bit by a throttle body and the whine of a turbo. Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 24, 2002 Share Posted August 24, 2002 my setup is a 2.9L nismo dish piston block that was heat treated, knife edge crank, counter weighted, shot peened, and titanium sleeved with 100 over... Ok, I gotta have more info on this one,(I know I'm not alone here). Tell us what you can about this titanium sleeve. And is 100 over the overall size of the sleeve or the bore? I have never heard of a titanium sleeve are you sure it isn't something else titanium? And why was it sleeved in the first place? Again, it is the first time I have heard of someone having to sleeve a L6 block. Sounds like a lot of prep on the block and such, more than many all out race cars. More detail would be appreciated. -Bob Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 24, 2002 Share Posted August 24, 2002 You will likely never hear a sound finer than sidedraft webers and a L series 6 with compression and a cam running thru the gears. Can I hear an AMEN! Reminds me of the older ferrari sounds... -Bob (I always post in twos, don't I? Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 24, 2002 Share Posted August 24, 2002 Why call somebody out? Why not simply ask for more details. I do that when someone puts a post out there like the one asking about what to do with all the hoses when removing FI and going to SU's. Breaking someone's post down into parts and responding to each section you have issue with is not going to make friends out of the people you are doing that to. I in no way consider myself to be an expert. All I know about sunbelt is they are in Atlanta, they can build Datsun engines, they take a long time to get your stuff back, and they are expensive. Good work takes time and it is expensive. I couldn't tell you where Robello is, or that Potter guy, and don't really care. I am not ever going to run into them, and on the off chance I run across one of their engines in the street, what do I have to loose? I mean if you pay 5k for an NA engine from one of those guys, and can't thoroughly thrash my junkyard motor, you are going to feel kind of small. At least I would. If I am going to spend big money on an engine, you better believe I am going to spend it on my turbo engine. Here is another tidbit I learned. When I lived in Auburn, there was a guy there who spent some big money getting someone (not sure who, but I am sure they were well known) to build him a 3.0 liter engine. This was back when 3 liters were like OMG you have a 3 liter. Anyway, it was all balanced, forged venolia's, not sure what head, header, Electramotive cam, and 44 mm solex carbs. It wouldn't fall out of a tree. A good running 240 with a cam and a header would have just spanked this thing all over the road. Moral of the story, just because you spend good money on something tried and proven doesn't mean someone else hasn't figured out something better. My friend and I just laughed our heads off at the guy who introduced us to a P79 head. He told us all the reasons why it was better, but we knew from all our reading, research and talking to people in the know that this guy was a few bricks shy of a load. When the car ran, and we rode in it, we believed. No one will ever convice me the P series heads are not the best. ( You won't convince my friend who is a mechanic either) All the pictures I have ever seen of the E31 heads that were modified by Gerolomy in CA were welded up and the chambers looked so much like the P series chambers, you would likely have to look at the casting numbers to tell the difference. The reason I so firmly believe in the P series is I have experienced the difference on 4 different motors. All four picked up dramatically when we switched from whatever head to the P79. We didn't do anything to them but cut em and swap over the same cam and go. You know, I can handle that people may think I am crazy. I have friends in town here that think I am nuts, which is one of the reasons I am actually building a P79 engine. Around here if it is a datsun and fast, it has a chevy motor in it. Mind you no one in my club has run faster than me except turbo6 guys. They bench race their 400hp motors, I got paper on my 307 rwhp motor, et's in my sig. I bet they freak when I give one of them a ride. Heck I might even get the thing done in time to take it MMP for the southeast Z party next month. Kind of doubt it, but I will have times posted one of these days. Also, bear in mind, I am an accountant by trade not a mechanic. I don't have any formal training with engines, all I know I have learned thru expereince, research, or watching someone else. I may not know the theory behind the physics of something, and I may not be able to give a canned answer about what something is, but I can hold my own. I make mistakes sometimes just like everybody else, and when I do, I can admit them. Anyway, you guys have fun. I will have my engine up and running before to long, but since I am taking a CPA review course this fall, all four sections, don't hold you breath waiting for results. I have to get my turbo car running too, and I am getting a turbo for it next week. Since the turbo car is fast, it will likely get placed ahead of the NA engine. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted August 25, 2002 Share Posted August 25, 2002 OK I need more info on that titanium sleeve deal too. Plus turning to 9k, woooweeee! I had actually thought of sleeving an L6 block with some of those ductile iron sleeves they are using for the honda engines to see if I could bore the thing out to 90 or 91 mm. 200hp na to the wheels is pretty stout. Clark at JWT has a 300hp na engine in his 240. There is some guy selling 2 inch su's on ebay right now. 800 bucks. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 25, 2002 Share Posted August 25, 2002 Okay, I guess this horse just wasn't quite dead enough... One thing that is still bothering me about the comparison that was made between the N and P series heads was the statement: The reason I so firmly believe in the P series is I have experienced the difference on 4 different motors. All four picked up dramatically when we switched from whatever head to the P79. We didn't do anything to them but cut em and swap over the same cam and go. ...and at least a couple of other allsuions to this same point. Since this was said several times, I have to believe that this is what was meant - i.e., P-series cut .110" vs. N-series uncut, everything else the same. What I'm getting at is that it appears that no effort was made to check the actual valve event timing between the two setups. I did the math for this, and as it turns out, milling the head by 0.110" will retard the cam timing by about 5.6 crankshaft degrees. This is quite alot, and is definitely enough to render any difference in the head itself completely irrelevant. My personal opinion is the same as JohnC's - the only relevant comparison to be made here is stock vs. stock - once you start talking about modifying the heads, then all bets are off. Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 25, 2002 Share Posted August 25, 2002 Datto, Thanks for the info, but it just doesn't sound right. Are you running a 240 crank and huge pistons? That would then support a high rev limit like you say. with a 2.8L crank,(or a stroker crank for that matter), you start to get into serious piston speeds at 9k rpm, F1 type piston speeds, and that doesn't include the crank resonance at that rpm. The full blown race motors I am familiar with only turn to the mid 8's. I don't doubt the numbers you claim as far as power, or reving to 9k, but two areas just seem way out of wack for me. 1: Titanium anything as a wear surface. You may have titanium rods, or titanium spring retainers, or something else, but titanium is just not used in a cylinder as a wear surface. Let me put it this way, (and don't take this wrong, I just think you are mixing up something), but I was at the carwash yesterday. The "resident" or the crony who goes around and empties the trash, makes sure the stuff is working, etc.. started asking me about my car,(the BMW), we'll just call him Genius for now. I started talking to him about my road racing,(instructing with NASA), and he then made the following set of comments: Genius: Yea, I would ask you to race, but I bet its pointless. Me- well, I don't really race except on the track, but it can hold its own. Genius - yea, well I have a CRX with a twin turbo V6 with nitrous so its pretty fast, but i'll bet you could beat it. (more comments followed, I wasn't about to egg him on). I did press the v6 issue, but dropped it when I realized he didn't know what he was talking about. My point? The v6 only came in the Accord with an automatic. There is no twin turbo kit out there, unless you have serious cash and want to completely fab one, plus fab a serious adapter to mate the engine to a manual tranny. And to fit all this in a CRX to boot. Now obviously this guy was a moron, and that is not what I am saying about you Datto, but when you say a titanium sleeve, it sounds as far fetched as a twin turbo v6 accord motor in a CRX with a manual tranny. I have seen steel inserts, iron inserts, and even carbon and silicon inserts, but never titanium,(let me clarify see, meaning I know of, or have read about, I have seen only normal sleeves). Again, I am not relating you in any way to Genius, but rather showing you how crazy it sounds to me. I also realize it is what you were told, so you have no way to know otherwise. #2 -Using SU's that aren't modified for that kind of revolutions and power. Again, not saying I don't believe, but stock SU's and even SU's with SM needles, or aftermarket needles won't support that kind of power or rpm. They need to be bored out and custom needles made or very seriously modifed. I have done airflow testing on Z SU carbs, and even Z therapy modified shaft carbs,(He lent me the carbs for the project). They are designed to have full piston opening, (at top of carb), when the 2.4L motor was at a theoretical 100% VE and 7000 rpm. Which worked out to be about 150 cfm per carb,(just under 300 cfm - the sheets aren't right here, but you can calculate it quick if you need - it was within a few %). For a 9000 rpm 2.9L motor, assuming 75% VE,(reasonable for that rpm), it needs 363 fcm. Remember, that ~300 cfm was for 100% VE at 7k. Its actual VE is closer to 70%. That is why many who build strokers or 2.8L and put SU's on them have problems once they get over about 5-6000 rpm, the carb is maxed out. You can change the dashpot spring, and the needle, but that is some serious tuning. I'm not going to get too detailed, but when the dashpot is maxed out, you start increasing the velocity/pressure drop over the bridge,(where the needle and seat are), which will pull more fuel out, but it is no longer metered the same as it was when the needle was moving. So I am not saying you are wrong, but those two points stand out. Lastly, 100 over is a inches reference. You are talking about 88.5 mm pistons, to get your 2916cc's or 2.9L. I have a hard time refering to english when talking about a metric motor. So we are dealing with a 2.5mm overbore We would appreciate if the guy who built your motor could elaborate. I will also end with this: While waiting at a Z recycler in the morining for some parts, I met a guy with another Z. We started talking about our motors,(I had recently finished the 3.1L). He told me that his 2.8L with webers was putting out "Just over 500 hp". Needless to say, that gave me pause. I was nice to the guy and probed him further and found out that is what his engine builder had told him. I discussed with him full out race L6's and what power they really put out,(low 300's), and told him I'm sorry, but your car just won't put out that kind of power. He was very nice about it, and a little mad at his engine builder. His repsonse was his builder said that is what it put out on the dyno, and had told him such. Unfortunatly, that is unethical and sad. But in spite of the false power claims, the guy loved his car and the motor, even if it only put out 200 hp vice just over 500. That encounter, coupled with some "edjumacation" about dyno's and how you can play with the output from my builder I am wary of anyones power claims. (he showed me how my motor could suddenly put out "400 hp!", vice the actual 230 hp - you just play with the baseline/correction factor). This is not to say their cars aren't fast... but I know the power mine puts out, and cars like Norms I know what time it is capable of in the 1/4 mi. The best strokers and some of the true race cars taken to the tracks break into the 12's. To go faster requires serious work,(oh, and nitrous!). It helps weed through b.s. claims. Again, not saying this about you Datto. However, your information is second hand from your friend who built the motor, (as I understand). Because of that, I take it with a grain of salt. That being said, I would love a ride in it though! It is a great looking car, and you have done a good job with it. -Bob ever present skeptic Quote Link to comment Share on other sites More sharing options...
Guest DATTO Posted August 25, 2002 Share Posted August 25, 2002 i understand how it may seem that what im saying and was told that it doesnt add up to high revs, but the fact of the matter is i saw it with my own eyes and drove it for a few years and can say it was possible. my business partner when i first got the car, i let him drive the car, he wasnt aware that 1st gear gets up to 9k rpms in a sec....he then reved it to 10k on my autometer gauge. i screamed and said shift!...lucky the motor was fine..no blow by or irregular idle. i had many people talk to me about this subject many times, its hard for me to justify my claims unless i show them personally which i have done many times. ive spoken with norm about his setup vs. mine...we had pretty much the same numbers just different methods of motor build...he just felt my car would pull harder since his motor stops after 7100 rpms and mine keeps moving along. i wish i could show you first hand how the car revved and ran but i already sold my cylinder head to a friend of mine who wants to build a similiar motor. all i have is an mpeg of my motor revving from outside the car but i cant find the files of my car revving to 9k. sorry for having second hand information about my motor but thats what i was told and as for the SU's they might have had SM needles in them but i dont remember them telling me for putting them in...i did sand the insides and ran slightly ported N36 intakes...i promise you the car reved even past 9K. i wouldnt argue about it if i didnt do it. hopefully i can get more information to clear things up. take care! mike Quote Link to comment Share on other sites More sharing options...
Bob_H Posted August 25, 2002 Share Posted August 25, 2002 Mike, thanks for the reply. And I quoth myself: I don't doubt the numbers you claim as far as power, or reving to 9k Never doubted you got to 9k. It was the power produced with stock SU's and the titanium sleeves that I questioned. The rest about asking on your crank and such was to determine if anything else helped you get to 9k, not determine if you got to 9k.Revving to 9k, and actually producing power up there are two totally seperate things. I rest. -Bob edit: spelling, man I suck! /edit Quote Link to comment Share on other sites More sharing options...
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