Guest Anonymous Posted January 3, 2001 Share Posted January 3, 2001 I have read many of the suggestions on the various boards of hybridz and am looking for some concensous on my particular application. I am in the market for a 280z to build into a street/track car that can play with Porsche's (because I can't afford one!) The suspension/brake/body set up is pretty well defined and I know what I need there. However, I am in need of a power plant! What I am looking for is a motor that will rev to ~7000-8000 rpm for track use without blowing up and produce ~250+ rwhp. The GM swaps seem nice for hp but they will probably not do well on the track. The reason for the high rpm issue is to hold gears longer and be able to play with engine braking and take advantage of gearing where necessary. I have considered supercharging an L28 (or supercharging + overbore) but am concerned about costs. Turbo motors are an option but the reliability, heat issues and complexity of doing the swap are of great concern. The 4.6L Ford motors are an idea, but the swap seems combersome as the 90' engine does not fit well into the engine bay from what I understand. I would stongly consider beefing up a normally aspirated nissan 6 or 8 if it was cost effective and can be used with a t-5 and R200 (4:11) rear end. There is also the possibility of Northstar engines, but I think they are limited to automatics. Enough rambling, I look forward to your comments and suggestions! Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Guest pauli Posted January 3, 2001 Share Posted January 3, 2001 one thing to remember: if you've got the right gears, you don't *need* to rev high to have the same mechanical effect. and power is cheaper from a v8... you could go with a 327... i believe they like to rev a bit. as for engine braking, high compression and large cylinders can make up for lack of revs. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 3, 2001 Share Posted January 3, 2001 Why do you require 7-8k rpm again? You can make any engine work through gearing, power is all that matters. Engine braking is BS, with proper brake setup you will get maximum braking regardless. Superchargers are vastly inferior to turbos in EVERY aspect. In general, superchargers are more expensive, less reliable, make less power, and more complicated than a turbo system. Installing a turbo l28 will be easier than swapping in a non-L engine, it's a bolt-in swap as a matter of fact. And turbos are hugely superior to a supercharger in a track car since you can get full boost from a turbo over a wide rpm range, while you can't get that from a supercharger. Makes those long straights much shorter! ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Guest pauli Posted January 3, 2001 Share Posted January 3, 2001 morgan, calm down, it's ok... i feel i must ask the question: will this thread turn into a turbo vs supercharger fight, a pushrod vs ohc fight, a displacement vs revs fight, or is somebody just going to suggest nitrous? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 3, 2001 Share Posted January 3, 2001 Well this was never intended to become a fight . . . Lone, thanks for the welcome, very appreciated! As for the use, I will be using the car as a backroad burner and a weekend track car, probably mainly sprint events. My desire for high rpms is just my love for hearing the engine screem (I own an Integra GS-R, 8400rpm, what a song!), and the power potential available out of relatively lower displacement motors which develop power at the upper end. The 327 sounds like a good fit because it will give me the low-end grunt I was looking for from a boosted car. As for my claimed turbo "misconceptions", it is just plain physics and plenty of personal experience. For a turbo to produce boost you need exhaust gas pressure. This can be accomplished by getting the rpms up, freeing up the exhaust or using a smaller turbine which requires a lower volume of air to spool. All options for someone looking for a turbo motor. I however, am looking for a car that I can beat on at the track and drive it home without concern over overheating or other complications associated with a properly set-up turbo system. A high-strung turbo motor is great on the track, not so good to get home on. A modestly modified turbo will get you there and back but the guys with the more powerful n/a's will kill you. Superchargers are inherently simpler because they are belt driven and do not have the intake temperature issues created by a exhaust driven turbo. As for pushrods, I do not have an inherant bias against the motors just a concern over their reliability at high rpms IN A MODESTLY PRICED MOTOR! Sure you can build a big block for 50k that runs at 9 grand all day but I am looking to keep the entire car price under $10k! The 327 spikes my interest, I have always been a big fan of this engine, please tell me more! Thanks to ALL! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 3, 2001 Share Posted January 3, 2001 Oh bye-the-way Morgan, if my statements are so ludicrous, respond to them with solutions, not just by throwing accusations around, this is a DISCUSSION board, not an argument board. Talk me into a turbo, not away from turbo owners. Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted January 3, 2001 Share Posted January 3, 2001 someone missed their cheerios again Morgan, too bad you deleted your 'meaningful' piece for that what you decided to share with us. IMO nothing Roamer said deserved your public prod and I appreciate others keeping it civil. It's more fun discussing thoughts than tossing **** IMO. Great to have you here Roamer If hp were just rpm we'd all be running very different setups. If you're into rev's and not too gungho on turbo's I'd sure look at a 302 Ford (small/light/fine power/easy to stick in, just parts cost a little more up front), 327 or 302 Chevy (you can buy cranks to build any of these if you can't find them used, I have a '68 327 in my garage available that I twisted relentlessly and it's seen 7-8k (not on purpose) a few times and still looks great). Above can twist 8k if needed but 6.5-7 yields a much friendlier street motor. Roller cam's just ice that cake:-) Northstar's can be done rwd but not worth the effort for gains/cost IMHO. At first you scared me with your engine braking comment (it's been instilled in me by instructors brakes are cheap and engines are expensive/use your brakes to brake not engine!) but then you quantified your use for those less experienced in your planned track use. I strongly feel you won't loose any engine braking with a 7k rpm V8 vs. a 9k Vtec etc. (my V8 has more braking at 4k or 5k than most....I love using it in corner's at lower speed). I'm not sure what gears/powerband you're looking for but it's hard to beat (or convince us to build differently might be more correct) a nice and simple 'lower' v8 power band of 3k-6.5k or 4k-7k depending on your build. I feel my V8 leaves a lot less stress on me to be able to handle roadracing transitions as I can still drop an Lt1fbody like a stone on corner exit if I get stuck at 2500rpm on exit..... I don't care if I"m playing 3k-6.5k or 5k-8k but as it's my daily driver/streeter etc no point wasting 5k rpm the other 98% of the miles I put on my ride. PS Torque is the silent winner:-) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 3, 2001 Share Posted January 3, 2001 If you like the sound, then there is no replacement for a straight 6! 'cept for maybe a 60deg v12, but I doubt one of those nice ferrari engines is exactly affordable. You said: For a turbo to produce boost you need exhaust gas pressure. That is false. Turbos get roughly 1/2 of their power by extracting enthalpy from the exhaust. This consumes absolutely no power at all, which is mainly what makes turbos so efficient. The remaining power comes from exhaust pressure spinning the turbo. You said: Superchargers are inherently simpler because they are belt driven and do not have the intake temperature issues created by a exhaust driven turbo. I don't consider a belt simple, it mandates placement of the supercharger at the front of the engine. Also, a supercharger is LESS efficient than a turbo, thus a supercharger heats the intake air MORE than a turbo. The heating of intake air is a result of compressing the air, not because a turbo is hot. This is another misconception you've fallen for. All turbomachinery operates more efficiently at higher speeds and temperatures. This is why so much money is dumped into materials research to develop materials for turbine components that can withstand higher speeds and temperatures - it is basically free power if you can spin a turbine engine faster or run it hotter. On that note, notice that a turbo can exceed 100,000 rpm with ease, while a supercharger is geared up from engine speed, typically around a 1:10 ratio. So if your engine spins 7k rpm, a supercharger will only be spinning roughly 70k rpm. 100k > 70k last time I checked. Belts and gears also contribute to a supercharger's horrible efficiency and reliability(horrible being relative to a turbo). Also note, that since a supercharger turbine is always spinning at a constant multiple of the engine speed, that a supercharger makes boost depending ONLY ON ENGINE SPEED. A turbo on the other hand, spins faster with higher engine load, and thus is not based on engine speed. Thus, with a properly designed turbo system, you can have a full xxpsi of boost over the ENTIRE upper 1/2 of your engine rpm range, while with a supercharger you simply cannot do this. We are of course talking turbine superchargers, not positive displacement superchargers. You said: I however, am looking for a car that I can beat on at the track and drive it home without concern over overheating or other complications associated with a properly set-up turbo system. A high-strung turbo motor is great on the track, not so good to get home on. A modestly modified turbo will get you there and back but the guys with the more powerful n/a's will kill you. A turbo doesn't add any heat to your cooling system except when under boost! When under a vacum, there is a pressure DROP across the compressor, which actually will slightly COOL the intake air. A "modestly modified" turbo l28 will get spanked by a non turbo? What I would consider a "modest" turbo engine - big turbo, good quality engine management and fuel supply, and a basically bone stock engine - will make waaaaay over 300 horsepower at the rear wheels and be more drivable than a stock 280zx turbo. Ask anyone here who has a l28 turbo, there are lots of them, and they will tell you the same thing. ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Guest pauli Posted January 3, 2001 Share Posted January 3, 2001 turbos make my head hurt. Quote Link to comment Share on other sites More sharing options...
John Scott Posted January 4, 2001 Share Posted January 4, 2001 quote: Originally posted by Morgan: I had a meaningful reply all typed up just now. But I deleted it because nobody cares and someone would get their panties in a wad and cry to have it deleted. Let him believe what he wants, I no longer have the time to worry about people who believe such ludicrous misconceptions and so badly want to continue to do so. Morgan, you're missing something here. Its OK to have differences of opinions without the hostile angry remarks. We're talking cars, not life or death ultimatums! I'll be the first to add that the Superchargers are not the power robbing complicated, expensive systems as you proclaim.I'll agree that roots type blowers are inefficient, but beg to differ with centrifugal. Yes turbos offer more hp through out a wider range and are superior in most regards. This also depends on application, engine size. The adibiatic efficiency of centrifugals is nearly identical to turbos. Plus you dont have the high underhood temps. Figure in the cost of one of the new no-lag turbos for a custom engine,it won't be a bolt on(!) tubing, fuel system and you're talking thousands more than a good supercharger.You can have a bone headed simple kit for about 2K that will make a ton of hp. A single sepentine with a tensioner is not complicated. To say that they don't make big boost is untrue. How much is a good #? 12, 18 25? A turbo is hugely more difficult and expensive than a centrifugal, except if your platform made one readily availible from the factory. Morgan, I wish you lived near by and we could trade rides. I think that my 16 psi pump gas driven Z would have you thinking differently about superchargers. No lag, no detonation, no overheating, as docile or wild as you want. Reliable? Yes. If you're ever in CO, I'll be glad to let you take it for a spin. JS [This message has been edited by John Scott (edited January 03, 2001).] Quote Link to comment Share on other sites More sharing options...
SpeedRacer Posted January 4, 2001 Share Posted January 4, 2001 Welcome Roamer - I've got to agree with Ross C, Pauli and Lonehdrider on the SBC. If you build a Chevy 302 it has a 3" stroke with a 4" bore and it will easily rev above 8,000 RPM all day long. If you build it light it will not weigh any more than the old L6 you replaced. Now, add to this the fact that it is a very low (V type vs. tall inline SOHC) short engine that fits completely behind the front axle and you will actually improve the handling of the car. You will have better weight distribution (usually close to 50-50) and a lower center of gravity. All in all a pretty impressive package. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 Now we are talking!!!! Morgan, thanks for joining us again! The heat issue was underhood temps due to recirculating gases, not necessarily limited to intake temps only. The hp comparo was an unfair one between larger displacement motors, but you have me intrigued with the 300hp numbers, due tell . . . After talking with a local sports car guru who has owned and raced everything from hondas to vettes, as Jake Blues once said, I HAVE SEEN THE LIGHT!!!! What I am looking for is a motor that weighs NO MORE than the L28, can produce ~300hp, is both durable and reliable (these are two DIFFERENT things), will serve me well in club racing track events (road race sprints), and send me flying through the backroads of my hometown! I am open to ALL options, turbos, na's, pushrods, OHC, etc. It will NEED to be attached to a 5-speed and the rear end will depend upon the power characteristics of the motor. HP is HP, either way it lights up the rear end, so Bring it ON!! Only one catch, it needs to cost less than 4 grand. I know, this tosses some, but let's get creative. Those that said they can get 7k out of a v8, how do you keep the valve fload to a minimum? From what I hear, 6500 is the most you can reasonably get out of a pushrod motor, but if you know otherwise, let me know. Of course to make this work, I need to know the approximate weight of the L28 as a starting point, and discussion that sells me on your point, not disparage other's. Thanks again for what has been very enlightening! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 Oh just another thing, I am looking to improve upon the weight balance of the car f/r and up/down to improve handling along with power, in case this got lost in all the motor talk! Quote Link to comment Share on other sites More sharing options...
DavyZ Posted January 4, 2001 Share Posted January 4, 2001 Roamer, if you want to build a Chevy motor for about $4K and want it to sing into the 8000 rpm range, then I would direct your attention to David Vizard's book: How to Build Max Performance Chevy Small Blocks on a Budget. He talks about light reciprocating mass: ie lightened Scat cranks, etc. If you are handy with tools, you can build an awesome motor using all the tricks and staying in budget IF you shop for bargains and don't skimp where you shouldn't. Read the book and you'll be very informed. Hope this helps! David Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 Try this link: http://www.angelfire.com/tx/Chevy302/my302.html He's got a 260Z with a Chevy 302 in it! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 Roamer, Pushrod engines can indeed turn high revs. The problem is, they usually don't do it inexpensively. To turn high revs, the pushrods need to very strong but light, the rockers need to be roller (as does the cam lifters) with stud girdles to keep everything square. The valve springs should be double. The crank needs to balanced extremely well, with light reciprocating pieces (usually like aluminum rods, but they aren't practical on the street and can have issues of failure after long hours of service due to fatigue). The crank needs to be like a extremely strong steel alloy, with like knife edged counter balancers. Oil windage trays must be used to keep oil off the crank. I think your getting the picture. Set up like that, a Chevy SB wil run 8k no problem. I actually saw a SB Chevy in a Econorail that would wing up to 10,000 rpm's! Of course it wasn't going to do it for a whole season without serious maintanance. I think setting the RPM's to like 6500 on the chevy would make it much cheaper, and believe me, the rush from the acceleration and the sound will definately impress you. 300hp is really just snoozing for a Chevy SB, that can be done not exceeding 5500 rpm's with some stock parts. A few hop up items gets you to 400 without alot of work really. (the original HP 327 could make 365HP out of 327 cubes. It was a screamer and had a REALLY satisfying lope to the cam). Oh well, just some additional items to mull over or confuse! Lone Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 In response to the current responses: Morgan, engine braking is not BS, if you spend any time on the track you would realize that in certain high-trffic situations engine braking is your best friend and it also allows you to "brake" with the rear-end only, in situations of understeer where a shift to front weight bias would only make the situation worse. As for superchargers being vastly inferior to turbos I would respectfully disagree. While everyone knows that turbos are more effecient and capable of higher boost levels you still have spool up problems unless you get sequential turbos (one small one for low rpms, a larger for high rpms) or expensive mid-sized ball-bearing turbos. The supercharger can provide the low-end grunt that the engine would not otherwise have and use a hot cam and high-rpms for the upper-end power, giving a nicely balanced powerband. Pauli, while you don't always "need" high rpms, it is an engine characteristic that I look for and also is a component of high hp (hp is torque applied at a given rpm). Remember weight is my enemy. Sure a big block will produce gobs of power but you still have to carry the thing around! While the V-8 is a great option I am not interested in a pushrod engine, just a personal bias. Overhead cam engines are more durable when used in track racing situations and are easier to maintain/toon without ripping the motor apart. If I could get that beautiful Mercury 32 valve v-8 . . . Keep it comin' guys! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 There are no "spool up" problems in a properly designed turbo system. You are merely repeating stereotypical situiations that get perpetuated by people who don't know what they're doing or talking about. A properly sized turbo does not have any significant lag when properly setup. Thus you have more low end power than you do with a supercharger since you will be running more boost than a supercharger could provide. It seems to me that you think you know the answers to the questions you just asked. I will answer for you from your own statements: You cannot have pushrods or a turbo. You want lightweight, lotsa revs, and a supercharger. Get a 4 banger or an aluminum v6 and an appropriately sized supercharger. Problem solved. ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Guest John Adkins Posted January 4, 2001 Share Posted January 4, 2001 Just wondering,what makes you say that GM motors "...probably wont do well on the track"? Small block Chevys have been pretty successful on the track in various forms of racing for the last 40 or so years, haven't they? They still hold up on the track in NASCAR these days (hours of high RPMs).... quote: Originally posted by Roamer: What I am looking for is a motor that will rev to ~7000-8000 rpm for track use without blowing up and produce ~250+ rwhp. The GM swaps seem nice for hp but they will probably not do well on the track. [/b] Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 4, 2001 Share Posted January 4, 2001 Roamer, Welcome if that hasn't been said yet. What form of racing are you desiging the engine to? If your considering a V8 and want the RPM you'll need a short stroke for sure. The GM's will work, they routinely twist sprint car engines to those rev ranges without a problem. Another motor although more difficult to find would be like a 302 chevy which was designed for Transam racing during the 60's. 327's as mentioned are a high winding motor that works will, you'd probably want a large journal 327 for that route. Another option is Ford. The 302 with a decent bottom end will RPM ok. See the Featured Cars at the opening HybridZ page and look at Terry Oxandale's Ford powered Z racer. Very impressive. Oh well, those are a few things to toss in the hat, good luck with whatever you decide to use. Regards, Lone Quote Link to comment Share on other sites More sharing options...
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