240Z, 260Z, 280Z Performance / Technical Discussions related to performance motor enhancements, upgrades.

Performance Upgrades for Max HP

Old 05-08-2005, 01:20 AM
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Performance Upgrades for Max HP

Now that my Z is going to be running again, I am thinking about doing performance upgrades as I make more money. I already have a list of parts I want to buy, and I just want some input as to if I'm on the right track or not. So far, I've come up with:
  • Moderate Lift Cam
  • New Lash Pads, Lifters, Springs, etc.
  • MSA headers, 2 1/2 exhaust that terminates into a glasspack
  • Fidanza aluminum flywheel
  • Centerforce Clutch
I don't really have any other ideas as to what I could do. I have converted my points over to the Pertronix Electronic Points kit, which actually gave it some more power, and I have bought all new timing pieces, so the timing is dead on. As I said, any suggestions are appreciated.
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Old 05-08-2005, 07:57 AM
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Jeremy,
I have built many a Datsun L-series over the past 15 years. When it comes to making good reliable power for the street, you approach the L-series a little different than you would a typical American V-8. With the American V-8, the cam is typically the first place most people start, but with the L-series, the cam is the last item to get upgraded, unless it is wore out of course. To help you understand this a little better, think of the camshaft as the ATTITUDE of the engine. The stock Datsun attitude is already a radical attitude compared to the American V-8’s. Torque peak is between 3500-4000 RPM, HP peak is around 6000 RPM. And that is with the stock Datsun Camshaft! This power band offers the typical high performance car nut the best compromise in low end torque and high end revs. To get your power band in that range with an American V-8, you NEED to do a cam swap. Now if you replace the Datsun cam with more radical cam, you are going to gain just a little more HP but at the expense of low end torque. To get the most out of a more radical cam, you HAVE to open up the exhaust and unshroud the vales in the head. If you just add a cam to an otherwise stock engine, (stock exhaust, etc), you probably wont gain any HP and WILL loose low end torque, no gain for a LARGE sum of $$$. In short, if a cam is one of your MUST have’s, you first have to allow the engine to breather more to take full advantage of that cam, i.e. header, exhaust, and valve unshrouding, oh, and have you priced Cams, lifters and matching springs for Datsun cams lately? OUCH!!!
Here is an example that I have repeated on several L-28 powered Z cars.
My personal ’75 280 Z, (280’s are known for the being heavy cars), with an internally bone stock L-28 with the factory smog ’78 camshaft, factory EFI, ran 14.4 secs @ 97 MPH in the ¼ mile, 0-60 MPH in 5.7 seconds and got over 25 MPG, (recorded an actual 28 MPG on one trip to the Shasta Datsun meet back in ’92). Just mashing the throttle in first gear at any RPM, without feathering the clutch, the car would fight for traction. Very fun L-series powered Z car. I have built several other L-series 6 cylinders for others that were comparable to this example using the same package. I only put bigger cams in the engines if the car is a dedicated race car only, when the engine will spend its entire life above 4000 RPM.
Any how, here is where I focus my attention whenever I am building street power…


1) Free flowing exhaust with header. Single 2.5” or dual 1.75” with a balance tube.

2) Lightened flywheel. Helps acceleration a BUNCH mostly in the lower gears.

3) Ported head. For the street and mild race I prefer to use the Z car N-47 and the P-79 ZX heads and unshroud the valves and blend in behind the exhaust seat to the exhaust liner. The Valve unshrouding should be left to a competent DATSUN tuner who has had experience and success with this as “John Q Public” could make the air flow worse than stock.

4) Recurved ign advance. Helps the bottom end power band from idle-3000 RPM or so.

5) Tuning, tuning, tuning…Getting the Fuel mixture AND timing curve just right for all conditions throughout the rev range.

Oh, and as for clutches, a good aftermarket clutch is never a bad thing to have, though I have found the stock clutches to hold up to my hot street engines just fine even for autocross, track days and occasional drag racing, especially if there is a lighter flywheel, (less stress to the clutch and drive train when launching hard and banging gears), and you use a good quality NEW clutch pressure plate and clutch disc, NOT a remanufactured unit. The Reman crap will bite in the **** every time…


Hope this helps,
Good luck,

Paul (BRAAP) Ruschman
’75 Datsun 280 Z-28 SOLD!!!
0-60, 4.2 sec.
¼ mi, 12.3 @ 113 MPH
http://www.datsuns.com/projects/paulrproject.htm

1996 Infiniti Q-45
2001 Chevrolet Suburban
1990 Chevrolet Silverado extra cab, 5.7L
SHO powered 280 Z under construction
LS 1 V-8 powered ?????

Last edited by BRAAP; 05-08-2005 at 08:05 AM.
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Old 05-08-2005, 11:19 AM
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yeah, that definitely helps. I have a P30 block with E88 heads, and from what I understand, the E88 is one of the most free flowing heads in the L24 series motors. I definitely want to get some headers, because I know I will get some performance gain right there.

As for cams, I was just told that getting a cam just a little more moderate than stock would give me a pretty good horsepower gain, but I do agree with you about the engine being pretty "torquey" from the get go. What you described with your L28, and the loss of traction in 1st, I experience the same thing. I priced out the cam and other parts that I would need to do a swap, and I'm looking around $600.

I just want to get the best performance I can while retaining the stock block and heads. I'm definitely a Datsun Purist, and I'd never imagine dropping a V8 into my Z.
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Old 05-08-2005, 11:57 AM
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Yeah I used to be purist as well. In fact I still love the L-28 and that BRAAAAAP exhaust note of a nicely set up exhaust. The V-8 definitely isn’t for everyone, but for those of us that crave that set back in the seat feeling that equals to or rivals the Z-06 Vettes and Dodge Vipers, the V-8 Z is one the least expensive ways to get there and still retain the Z cars docile manners.
In my purist days a close buddy in Z club had a pretty quick V-8 Z. I always thought the V-8 would weigh the nose down, be harder than heck to drive around town, bastardized the car, etc…. That was until he took me for ride and let me drive it. That single ride changed my whole attitude. So I sold my hot little L-28 and built a nice little 350 with 5 speed. The engine Idled at 750 RPM, glass smooth, no lope. Shift point was 5500 RPM, with a holley double pumper carb it got over 20 MPG on the freeway. Now this is the best part. It ran 12.3 secs @ 113 MPH in the ¼ mile on some real cheesy 195 60 HR 14” tires!! 0-60 MPH was only 4.2 seconds! Launch in 2nd gear and shift point was just past 60 MPH. My 0-60 MPH was limited to 4.2 secs due to traction as it would spin all the way to 60+ MPH. That is dead even with the Dodge Vipers of the late ‘90’s!!! Now get this, 2nd gear with the welded up diff in the car would SPIN the tires at ANY RPM just by mashing the throttle on dry pavement. 3rd gear would break the tires loose as the engine passed through the torque peak, again on DRY pavement. In 4th gear, with a little coaxing from the clutch, the tires would break loose and spin all the way up to redline WHILE doing 65 MPH on the freeway, again on dry pavement. If the pavement was wt, 5th gear would break them loose at 65 MPH in the wet just mashing the throttle. (A few nay sayers said BS, so I took them for a ride, now believers). This technique works AWESOME to get a tailgater off your butt! They immediately hit the brakes when they see you getting loose, leaving tire smoke at 65 MPH on the freeway! As for weight gain? My car only gained 125 lbs with the V-8 over the L-28, 75 of those pounds were on the REAR wheels as the V-8 sits LOWER and further back in the chassis than the L-28. This gave my car a 48/52 weight distribution, 52% on the REAR wheels! If I went with aluminum heads, aluminum water pump and few other light weight parts, it could easily weight LESS than the L-28. The car was just as docile to drive around town as the little L-28 was. My wife and my aunt drove the car on several occasions and never complained about the car being a monster.
It is pretty hard not to like a Z car that has twice the engine displacement which carries twice the power and torque as the L-28, is just as easy to drive around town, is LESS expensive to rebuild and get more power out of than the L-28, and will beat up on Z-06 Corvettes, Dodge Vipers all day.
My best friend and a couple of other friends rode in and drove my car, (one was a turbo L-series die hard and would never think of V-8ing his car, Ron Tyler), converted them over as well. Ron Tyler was the turbo guy, he has since done 2 V-8 cars, (currently working another Turbo L-28 project in his 240-Z). His first was an LT-1 with 6 speed, second was a project to see how cheaply a V-8 Z car can be done including the purchase of the Z car and complete V-8 Powertrain. It finished in at under $3000, this included new headers, exhaust, aluminum intake and carb, aluminum cross flow radiator, new tires, etc. Car ran 14.0 @ 100 MPH, fun spunky quick Z car.
Ok, enough how great I think the V-8 swap is for a car. It isn’t for everyone and this fine. I commend any one that can resist the temptation for crazy power and stick with the proven reliable power plant that has and an exhaust note that even a BURLY V-8 can’t match.

Good luck and enjoy your Z to the fullest…
Paul (BRAAP) Ruschman

Last edited by BRAAP; 05-08-2005 at 12:02 PM.
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Old 05-08-2005, 12:53 PM
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yeah, the V8 isn't a bad idea, but as I said, I tend to be a purist. I've actually thought about buying another Z once I get mine to the perfect condition I want it, and building a V8 with a scarab kit on it and what not. I like the L24 because it has excellent gas economy, and is still fast as hell.

I just got done putting my engine back together, and I still have yet to put it back into the Z. I have to save up some money for insurance and what not, but I can't wait to put the motor back in and get my Z back.
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Old 05-18-2005, 07:59 AM
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Originally Posted by J-U-ice
For another option for the engine swaps, I don't know how hard it is to get where you guys are, but in Australia RB series engines are very easy to get hands on, and are good for a power upgrade. A guy I used to work with put a RB26DETT from a GTR into his 240Z, went very well indeed.

But even a RB20DET would be a good option, and considering they are dirt cheap, might be an idea?
They have a very sweet engine note too and easy to get 200rwkw out of, or more if u want.

State side you are looking at a minimum of $2500 for the RB front clip.
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Old 05-25-2005, 05:12 PM
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Turbo thoughts?

Hi from a newby. . .at least its been a looong time since I was here last . .

Have you thought of attaching a turbo? Im one of those Australians mentioned above and had a long look at the RB engines and while they make heaps of HP, I just preferred the L Series engine under my bonnet. Ive got about 310 RWHP at the moment, but am only running 15psi and have had the boost at around 20psi, but the car was just sideways everywhere. . .

The beauty of the LSeries is its cheap to build/rebuild, RB's can be quite expensive and they're bulletproof (well. . . almost)
Check out what I've done to my engine at www.240z.id.au
I realise you're a bit of a purist, but I suppose like everything it depends on how much of a purist you are.

Cheers - Simon
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Old 05-25-2005, 05:58 PM
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Yeah, I'm a purist, to an extent. The Z is an excellent car the way that it came from the factory, and that's what I like. After actually getting the Z running again, and taking it out for a little spin, I'm suprised with how much power it has, and how much I forgot it had. I think that some headers would make a little bit of a difference in power, and I'm going to rebuild the carburetors and get some more horsepower. I'm also going to buy all new u-joints for my driveshaft and rear axles, which should get rid of some of the slop and give me rear wheel horsepower.

I've thought about turbocharging my L24, but from what I understand, the stock internals can not stand up to boost. I do know you can build a turbo motor, but I think I'll take my other block and make it a stroker motor; I hear they make some serious power.
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Old 05-25-2005, 05:59 PM
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by the way, that is one beautiful Z you have Simon, you aussies sure do know what you're doing!
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Old 05-25-2005, 07:32 PM
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Thanks for the kind comments Jeremy,

L28 is the way to go. . .Mine has a stock crank (deburred), stock rods (shot peened and polished) and my pistons cost me somewhere in the vicinity of $300 Aust. .
My head is a P90. . sure Ive done a bit of ceramic coating, porting etc but the L Series engines are pretty robust. The L28 also looks just like an L24 too, so for a (semi) purist its a good hp upgrade. There is an old saying that you cant beat cubic inches (or cc's in this case) for a performance upgrade.

I have seen a couple of turbo'd L24's though. . .there was one up my way racing, and going very nicely

Good luck with your project, Im sure you'll have heaps of fun along the way

Cheers - Simon
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