ZIPPY
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Posts posted by ZIPPY
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Wow that pretty amazing! I would love to get ahold of the programming he's using there.
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For the crasy people that like the Lka conversion 50mm itbs hi low injVery nice... Did you make the actual throttle bodies themselves or are they a premade unit that you fabricated the rest of the manifold around?
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I think the 290F cam looks a little better. Keep in mind that the advertised power band is still 3500-7500rpm. In your case with the L24 I imagine the powerband might be a little higher than the advertised. Unless your going to be living in the 7000rpm range is it worth having a cam that comes in at 3500+? The 270-80F grind makes some real power in the upper ranges (200hp+ with SU's) but is also relatively streetabel at normal driving rpm.
ITM flat tops. Hit 7900rpm fairly regularly. I think they might have very lightly kissed the head though. For cast pistons, I think they are very well made pistons.
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That is a huge cam you have there, looks to me like it should peak right around the 8000rpm range. To really take advantage of that cam you will be revving well past the pratical limits of cast pistons. It sounds like you are putting some money into this engine, and a piston coming apart at 8000 rpm would utterly destroy a very nice build.
With forged pistons you will be to fully enjoy your high rpm horsepower with the peace of mind knowing that it won't scatter itself all over the place. Extra cost for pistons now, or extra cost for a new engine later? Or rev limit an 8000 rpm engine at 6800 rpm.
I took my high compression cast piston engine to nearly 8000rpm on the drag strip a handful of times, but I got lucky and the only thing that happened was my pistons started knocking their skirts off.
Also I would get as aggressive of a port job as you can afford. You have a very nice exhaust and intake system, and you are already putting big valves in the head... Don't settle for light porting.
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PM responded too. Sorry it took me so long.
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I have a cam you might like. It is a Schneider 270-80F. I used this cam for a while and then had Jerry at Schneider re surface it for me so it is practically new again. This cams duration is 270 intake and 280 exhaust. 0.460 lift. It doesn't look too radical on paper but I was making over 200 rear wheel horsepower through SU carbs with this cam. Streetable but with lots of power.
I also have rocker arms that have been resurfaced and then coated with a bake-on dry film lubricant.
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How much are you looking to spend on one? I have a brand new Kamari adjustable sprocket. I forget how muck I paid for it, I'll have to check.
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For forged pistons on the cheap side look at Supertech Performance or Probe forged pistons. I know they make ka24 forged pistons for a lot less money than your usual names in the piston industry. Search their websites, find the part numbers you want and then fine th best price vendor.
If you want a custom set, talk to Elmer at Arias Pistons and he will fix you up. From them a complete custom set with rings piston pins and locks will cost about $900.00 out the door. They make an amazing product by the way.
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That's a nice looking oil pan there. I like the windage baffles. I have a question for you about the pistons. Can you tell me what your final valve pocket depth ended up being? I am having some custom pistons made right now and I want to compare numbers, maybe I can save myself from having to depen the pockets like your machinist did. It's funny how similar your engine setup is to mine, my head is way cut down, and our cams are very close too.
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I'm bummed I missed MSA this year, I would have liked to see that thing run. My Z wasnt ready anyway. What did you make on the dyno this time?
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Oh yea, I build those all the time... Its childs play, lol
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tI like that tensioner design alot. I have been toying wiht the idea of making a roller tensioner similar to the kameari design. What did you construct the slack side back out of?
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The same car is for sale again, but this time dressed up like an SR-71.
He says the tail numbers have a secret meaning and if you figure it out he will knock off $500.
@ TonyD - I imagine somewhere in your vast wealth of semi-useless information you might have a recollection of what this number signifies.
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My currant project is a nearly 14:1 compression E85 L28 with webers. Depending on how hard it is to get the engine started I was thinking of building an ether injection system as is used on some diesels. The diesel system consists of a pressurized ether canister and a push button operated solenoid, that delivers a small shot of ether to the manifold as a starting aid. I am deleting the enriching circuit on the webers and will be running a fairly large camshaft so I imagine I will have some difficulty getting the thing started in the morning.
I cant say I've ever produced ethanol for motor fuel, but I will admit to being able to cook up a couple gallons of a much tastier variety. It is possible that there are two gallons of 160 proof brandy on my counter top waiting to get cut down and aged right now.
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I got the cam from Kinetic Sunbelt in GA. With the springs they supplied (single - not double) they said not to run it higher than 7700 RPM, but that is close to 8k...
The seat pressure (installed) was checked and found to be only 56 lbf. At ~.550" lift, the springs were only supplying 190 lbf. Because the spring pressure is so light, my engine builder is strongly recommending the use of titanium retainers. The receipts just keep adding up.
Here are pictures of the work just now done to add PTV for the intake valves.
Garrett
Wow that is an incredibly light seat pressure! You're not worried about sealing issues or anything? My double springs seat at 125lbs and are 270lbs at .500. You will have much less valve train resistance than I will for sure.
As for the Ti retainers that is a must with pressure that light. I know Schneider cams makes a set for the L series. Not cheap by any means though. http://schneidercams.com/7titaniumretainer-73006.aspx
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Thats a hell of a cam! Almost the same as mine with a little less duration and a slightly smaller lobe separation. Sounds like this should power band around of 8000rpm. I am pretty much at this stage in my build, I just had to order a valve relief cutter for the pistons.
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Very nice.. Me likes!
I'd love to see some close up's of the linkage. Is the center to center of the itb's the same as the manifold?
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Damn, for once someone caught me in one of their videos...
Did I get you in the dyno video? Where are you at? Thats funny.
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I've got a mostly stock 260Z that is a typical "sunny day" car - but lately its been upstaged by my new daily driver - an RSX type S. Fortunately I just dropped my daughter off at college for her last year, so come spring I'll finally have a few bucks to sink into the Z. My goals are more subjective than logical:
- Feel faster than my RSX.
- Run triples. I know I'll probably get tired of tuning carbs and swap to ITBs or something, but I've lusted after Webers (or Mikunis, Dels, etc) for a long time.
- tHave a usable redline north of 7K RPM. I know its more efficient to make power at lower RPMs but I want to hear an exhaust note that makes me feel like I'm Paul Newman at Limerock.
- A smooth idle and linear throttle response.
- Run on 93 octane.
The RSX weighs about the same as an S30 and according to the internet puts down around 165-170 whp, so I'm thinking I want about 200-210 whp, or approx. 250 crank hp. I've been searching the internet and doing back-of-the-envelope estimates to figure out how to do that. What I'm leaning towards is (roughly) 88.5mm bore L28, stock L28 crank and rods, high-silicon forged flattops, 10:1 CR, quench head, 45mm triples, mild cam (aprox .490 lift, 270 duration). Mild cleanup port on the head - unshroud the valves - but don't go too big on the port to keep velocity up.
Basically a mild stroker build without the long crank (to give me my 7500 RPM redline without radical porting).
Things I couldn't find good answers for:
- Best way to get a 10ish CR with a quench head? Can an MN47 be opened up to 46cc combustion chambers? I'm nervous about the shim-n-shave mode for the P79; all those shims stacked under the cam-towers seems a little scary at 7500 RPM... Maybe go with the Kameari idler gears and adjustable cam gear?
- Is there any benefit to using L24 rods with the L28 crank? I've plotted the piston velocity curves with both rod-lengths and the extra 3mm just doesn't seem to amount to much? Keeping the shorter rods might actually help by creating more intake "vacuum" early in the intake stroke to squeeze a little more flow out of the carbs (45mm seems a little on the small side for a 250 hp motor). Any real world experience here?
- Undoubtedly lots of things i haven't thought of yet... I'm trying to settle on a block and head before I get into more details.
Opinions, ideas, experience welcome.
Don
Wow that was a lot to read... This thread is just as full of very useful information as well as usless BS bantering.
I guess thats one of the joys of forum engineering. Anyway, BS aside I'd like to reply to the original posters question about a 200whp daily driver. You are describing almost to a T my currant engine setup. It is a ZX block (F54 i think), P79 head, cast ITM 87mm flat top pistons, prepped stock rods, schneider cam and SU carbs. And yes I hit 7500rpm reguarly. Infact the last two times at our local parking lot drag strip I had the rev limiter set at 8000rpm and dug into it heavily a couple times. I was shifting out of second at around 7800 - 7900 mostly because my gearing is a little weird (t5 and 3.90). The only chance I had to dyno it was a the MSA Z bash last year. It made 196rwhp at 6200rpm and peak torque was 180 at 5000rpm... Remember this is with SU carbs. The parking lot air temp was like 110 and the carbs were out of sync. Oh yea, and cali 91 octane. In the vid you can hear it pinging some mostly due to there being no cooling fans and the engine was fairly hot, also I think the timing was a little over advanced. I'm pretty sure it makes decently over 200whp properly tuned at the rpm I usually shift at.
I will gladly provide more info if it will help you build an engine that meets your goals.
Here is a video of the dyno pulls I made. Watch to the end and you will see the dyno sheet.
EDIT - I should add that it is still a 2.8L and was daily driven until I took it apart a couple months ago.
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Hey there, I dont post a lot on here but this thread caught my eye for some reason. You want to run a high compression NA engine, go for it. Anyone who tells you not to go above 9.5:1 compression has no experience at all with a a high comp street car. So many people just repeat what they read somewhere else on the forum from someone who is repeating another post from someone who is guessing...
I have been running about 12.4:1 on California 91 octane in my car for almost two years now. 2.8L and SU carbs making over 200hp on the wheels on pump gas. People always tell me I'm full of $h!t until they race me, lol. I use a P79 head, flat top pistons and a schneider cam. Granted everythign had be extremely modified but you can proabably get almost that much power just by swapping to flattops and a Maxima N47 head (11.3:1). Or use a P series and do the 0.080" shave thing(mid 10's?). If you have easy access to e85 then by all means do that, and go even higher on the compression.
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....and strangely, one of my L24 head bolts seems to only have one thread, as in you could only turn it 360 degrees at max, kind of strange if you ask me....
Sounds like you have a broken head bolt... Have you checked your block?
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Hey all, long time reader here, but first time poster. I have found that the search button on this site has been one of the most valuable tools in building my Z.
I do have someting that I think might ad to the technical resources of this site. I also want you opinions on the subject.
Today I called SI valves trying to order their swirl polished stainless valves for the P79 head. JD from SI told me that those are a discontinued part and that no one else really makes swirl polished valves for the Z's. He said they could make me a custom set for about $30 a valve if I wanted.
Anyway I ordered a set of regular valves from them and decided to try my hand at performance prepping them. So far it seams that most people just chuck up the valve in a lathe of drill press and smooth/polish both its top and bottom. The intake only gets the bottom polished. Easy enough...
Then I found this article on adding "Powre Ringz" as the author calls them, to the intake valve. He claims that this helps with fuel vaporization and therefore promotes a better fuel/air mixture burn. His theory kind of makes sense I think, and might work like the "golf ball effect" to help gas flow across the valve surface.
Read it and tell me what you think.
Here's a link to the article.
http://www.allpar.com/fix/holler/valve-prepping.html
Here are the "Powre Ringz"
WTB L28 square port header with 1 3/4" primaries
in Parts Wanted
Posted
Actually Stahl is building and selling L28 headers again. I talked to Jere on the phone recently and he told me he had initially decided to drop the datsun stuff, but some other plans changed and is takin orders again.