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Thread: High compression N/A build question

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    Registered User Co0kieduster's Avatar
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    Default High compression N/A build question

    I'd like to do a high CR N/A build. I have an L24 e88 head with a fresh reground cam .460 280/280. Guessing the bottom end is stock. Dual webers 32/36

    After searching I don't see much info on using the e88 head for an NA build, everyone seems to be going with a n47 or p90 i believe

    My questions

    1st how do I know what block I have?

    2nd should I get an l28 with one of the other heads for a good NA build? And, if that's what I do will the cam I have work in the other head?

    3rd will the e88 make a good high compression head? maybe with some work done? or is this not cost effective?

    I am not an experienced mechanic....but I have been able to do almost all the work myself so far and would like to as I want this car to teach me as much as possible. The cam had to be reground due to a broken oiler and a wiped lobe. I have a friend who is a pro and he helped my check wipe pattern, timing and tune the car when I did the cam.

    My goals are somewhere close to 200whp

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    There is ton of info on this site and Hybridz on this subject-what info have you found by searching?
    If it's a l24 block it should be marked p-30. What year e-88 makes a difference too. The early e-88s are good heads-but how much compression do you want to run? What gas are you going to run? That cam won't allow a lot of compression on today's premium gas.

    200HP is a reasonable goal and there is a large thread at Hybridz right now covering this.

    The power is mostly in the head and lots of tuning. Probably tuning more than anything.
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    Oops forgot to mention that, with the e88 as my head, I was thinking of either boring out what I have .040 maybe and getting flat tops or using an l28 block with flat tops

    I can polish the head myself, porting out of the question. If that is a must for high CR then it would go to the machinist.

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    Yeah I read the thread they have up now where they got into about the higher rpms. What I couldn't find was info on using the e-88 for a high compression build. I was hoping to run premium i.e. 93. Anyway of telling the year of the e-88? If I had to guess I have a later year as when I pulled the wiped cam is was stamped "C" . I'm think around 10:1 CR.

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    Registered User beermanpete's Avatar
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    The best thing to do is pull the head and measure the volume of the combustion chamber and the valve diameters. These are the main differences between years.

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    If you have the head off, check out the thread on Hybridz covering different heads-they have pictures!
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    Great thread, if I had the head off, was reading it last night. I am just trying to compile information and decide what to do before I start any work. The Z is my dd right now, but being forced to borrow my gf's S2000 while its apart will be tolerable I suppose


    Just trying to avoid putting a bunch of work/money into something and finding out I could have slapped together a few part for half the price and reached my goals.

    I've read some conflicting info on CR I believe too. Many state that pump gas will work up to 9:1 others say 10:1 is the limit.

    If I can reach 200whp on 9:1 that's fine.

    Can anyone explain why the S2000 can run on 93 with an 11:1 CR but not the Z? obviously its newer technology, but whats the real reason?

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    Quote Originally Posted by Co0kieduster View Post
    Can anyone explain why the S2000 can run on 93 with an 11:1 CR but not the Z? obviously its newer technology, but whats the real reason?
    There are a BUNCH of reasons, but just a few would be rod/stroke ratio, fuel management improvements, ignition timing improvements, cooling system improvements, combustion chamber shape.

    You can reach 200whp on 9:1, and as I've said there a number of times, it's much better to be able to optimize the timing for power than it is to run too much compression and have to back the timing off so that you can run without pinging. Also your cam is too small and you should ditch the DGVs IMO.
    Jon

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    I knew I shouldn't have listened to all the "DON'T GO TO BIG" with your cam people.....oh well lesson learned. Another regrind possible right? new valve springs too.

    I'd like to ditch the DGV's, Can't decide if I should get SUs or triples....seems like SUs can perform, but the triples just have that way cool factor. Worth the money? idk

    9:1 is fine. I really need to find out what I have before I go any further.

    PO said the car had an L24, but the car is a 260z, and after pulling a "C" cam out of it (with .160 lash pads) im wondering what about my engine is actually L24 or if the PO just didn't know. This would be much easier if It were in pieces. Hey maybe the valve springs aren't stock either!

    Any Zcar experts in Eastern NC?

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    I'm not positive for the early blocks, but I think that if you look at your engine block, right above the starter, just below the head/block interface, you'll see a flat pad with some letters and numbers stamped in to it. L24, L26 or L28 are usually the first three symbols.

    The engine serial number follows. If the numbers match those on the ID plate on the strut tower, you have a "numbers matching" engine/body combo.

    If not, at least you'll have an idea what engine you have.
    Last edited by Zed Head; 09-21-2011 at 07:48 PM.

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    Sorry havn't had alot of time or money to work on the Z recently. Been doing some maintenance on the girlfriends S2000 and attended a few weddings which ate up all the cash and time. Anyhow, with some luck ill have a few bucks by the end of this month.

    Found out I have an L24 block. Thanks for the help on that, was really hoping to see L26 or L28

    Still can't decide if i should work with what I have, or just shop for a new block and head combo that will give me the CR and power I want.

    Not even sure from all my reading if the L24 e88 combo can net 200rwhp?

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    9 to 1 and 10 to 1 is not high compression. That's a normal engine compression range.

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    Like I said, the year e-88 head makes a difference. I am probably running close to 10:1 (40cc chambers) right now and have no problem running premium and full ignition-BUT-I have done things to the head to minimize detonation. 200 will a bit tough for a L24 without a big cam-but don't be scared of a bigger cam in these engines-they like it!
    TUNE! TUNE! TUNE! This isn't a bolt on deal
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    Do the Triples - you'll be glad you did!

    If I had it to do over again I would go on out and up to the stroker crank - a little bigger cam - 200HP at the wheels will take some $$.............trust me!
    Life's a journey; enjoy the ride!

    Mitchell
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    R180 3.9 Diff - Close Ratio 5 Speed - Toyota Vented Brake Upgrade w/ Porterfield High Performance Pads & Shoes

    1972 Datsun 240z
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    Ok, I'm going to revive this thread with an update. I just had the chance last weekend to put my car on the Dyno for free . My brother graduated top of his class and as a reward was aloud a free dyno run with three other top performing students.

    Anyway, I ran 108 max torque and 97 max hp. About what I expected.

    We didn't rev past 5500 rpms because the instructor was afraid my cheap tires would blow up. He said it might clime a little higher but not much.

    On the way home from Charlotte one of my carbs took a dump. I was told that a "valve" in the float bowl might be sticking causing it to flood those three cylinders. I have no interest in reviving the webers and am now saving my pennies for a set of triples!

    Ill be sure to post the print out as soon as I get home from work.

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    My advise is this. I have assembled a ton of engines in the past (albeit all ford and chevy V8's and a few lawnmowers). Do not get hung up on 200 HP or 194 HP or any HP number. Keep many things in mind. This is a daily driver, so having it run predictably and reliably should be of paramount performance. To get an L24 to hit 200 HP is going to take two things. A big cam and lots of compression. It is a balancing act really. Which means one thing. LOTS of tuning. If your into that, then great...but high strung engines require constant maintenance.

    What is FAR more important is getting all the components, from the oil pump to the air filter to be matched to work together as a system, and not fight each other. A well matched engine that is tuned perfectly that puts out 180 HP will be FAR more enjoyable than a temperamental 200 HP motor that is always on the ragged edge of pinging, and can't idle and overheats.

    Think robustness and reliability. And think part matching.

    You are going with triples, they excel at higher RPM operation. Great, this goes with your larger cam. You will need a head that can flow well with as smooth a combustion chamber as you or your machinist can make. This will help mitigate detonation. A cam with a huge overlap between the exhaust and intake valves will eat into your overall compression. Any large cam will make your idle somewhat worse and compromise your power brakes in repeated stop and go driving as they just do not pull that much vacuum.

    Growing up I was always the guy with the car that always ran, and was always fast. I never had the most money, but I buried my head in books and learned about the engines I was building from a basic level. What I learned is that money spent without knowledge is wasted. THe L series of engines were like coming home to me. The part interchangeability rivals the Small Block Chevy. Which is impressive. You can build quite the hot rod using nothing but OEM Datsun parts.

    I hope that helps.
    1971 240Z HLS30-38691
    93.9% done and getting better every day
    Now with 100% more DATSUN SPIRIT L28 Power
    1968 Datsun 2000 SRL311-03416

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    Thanks for the sound advise. I understand that 200 is just a number and I maybe should have said in my original post that I want at least 200. Just because i know that if I get close i wont know how to stop till I'm there or past it

    I wish I had more than a measly NC state teacher salary to work with....maybe someday when I quit and my dream business dyno/tuning shop in my back yard becomes a reality and makes me $$$$ i'll build it all at once.

    Until then, I believe i have a plan. Please feel free to bash it/correct it/have an opinion about it.

    1st get triples.... 45mm

    drive around with cool looking sounding carbs

    2nd pull head send to shop for port and polish, flow bench work...etc

    drive around with alot more power hopefully

    3rd....get l28 block with flat top and mate with worked head and triples for 10:1 CR

    Drive around with huge smile yay!

    I've attached the Dyno sheet, guess it was 111 torque. Also a pic of the awesome driveway GF drives the s2k. Yes she makes more money than me and has no student loans :/

    on a side note my z kept up with two ricers that were on the dyno that day as they both lost hp with pointless mods im guessing.
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    I think you need to do #2 first and run your car with the stock SUs and tune it the best you can. Meanwhile you can find a L28 and go thru it while your driving around with a big smile on your face. Then bolt your fresh head on the L28 and start looking for your triples IMHO
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

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    problem is I don't don't have the SUs. I bought the car with DGVs on it. I suppose I could get the $40 rebuild kit and try to get them working since they are leaking everywhere and one is definitely not functioning properly. I don't see much info out there for help however, if I run into problems.

    If I had SUs, then I agree completely, keep the SUs for now get triples later.

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    Rebello Racing is a great source of information for this sort of build. They were infinitely patient with me as I hit them with all these same questions. A five-minute conversation with them will teach you a lot.

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