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77 280Z - Looking for cost effective power


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Hello all,

 

I've had a 77 280z for a few months now. It's got a 75 L28e motor with the non exhaust lined head. Since then, I've converted it from automatic to 5 speed, 3.9 R200, decent paint job, etc.  My friend and I were getting the car ready for a long trip (1500 miles) doing routine maintenance when we heard what sounded like rod knock.  Well, a 2 hour basic maintenance trip turned into a 10:30AM to 5:30AM bottom end rebuild.  This was 3 days before my 1500 mile trip.  Regardless, the car made it with no issues!!

 

Essentially, everything has been touched in this car except for the wiring.  It runs great and is my daily driver.  Now I'm looking for some more power.  I've already done the basic stuff (auto to 5 speed, 3.9).  I do like the L28 motor, but I have no issues swapping in something better.  I am not looking for a crazy drag strip beast, just maybe upwards of 200whp with decent gas mileage (20+ would be great!).  I know generally power and gas mileage don't go together, but I know some of the Chevy V8's can get you 28+ on the freeway.

 

For a budget of $1000, what is the best way to go?  From everything I've read, it seems an L28ET may be the best option.  If I don't do a swap, will any upgrades to the L28 give significant gains within this budget?  There are still intake, headers, megasquirt, cam, headwork, etc.

 

My goals are a 'quick' daily driver, so I would prefer to keep the power band lower rather than higher.  Torque improvements would also be nice.

 

I'll be happy to give more information if necessary!

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The factory L28 ECU does not take well to much modification to the engine. Like Tony stated, there isnt really much you can do for only $1000 that will give you any noticeable power increases.  If you are planning on keeping the L28 and sticking with fuel injection (not switching to carbs) then going with Megasquirt would be a good first step.  You will not be able to "realize" any real power increases from things like a cam or doing port/intake work if you are still just going with the factory ECU since it cant cope with the changes.  Going Megasquirt first will not gain you much as far as power goes, but it will lay the foundation for future mods and will allow you to get the most of those mods.  

 

Another option for your $1000 would be to sink it into suspension (if yours is not already upgraded).  A nice coilover system, or even just some sport springs and struts can make a huge difference.  This will also set you up to be able to better handle any large power increases down the road.  Personally, I feel that having a car that can handle the turns much better is much more fun that a car with a little extra HP.  But that is my opinion as I am more into the daily drive on windy roads and autocross than drag racing.  However, be prepared for ride quality to suffer a bit.  Being as it is your daily driver, stiffening the suspension may not be the thing for you if you like a soft ride.  But you may not care about that all that much, or you may be able to find a nice middle-ground that works for your tastes/needs.

 

Good luck!

 

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Yes as a daily driver, I'm worried about going with a stiffer suspension and/or lowering the ride height. I'm in Tucson, and you basically need a 4x4 just to navigate these cracked and pot holed roads.

 

If there is a suspension mod that gives similar to oem ride but actual enhanced performance, I would be interested. The full suspension is rebuilt with urethane bushings, but the shocks and springs are the same.

 

I suppose I could save the money for wheels/tires. I was hoping there was SOMETHING I could do for power in that price range.

 

I love handling, but with all of the freeway driving I do, power seemed more usable.

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My goals are a 'quick' daily driver, so I would prefer to keep the power band lower rather than higher.  

 

A head port/polish job won't net any decent gains on the factory ecu? 

The factory EFI system is pretty crude.  Read the Engine Fuel chapter.  It's designed to give driveability and emissions at mid-throttle, mid-range RPM, then adds a bunch of fuel at the high end.  You can add more fuel for the high end to take advantage of your modifications, and run rich and dirty on the low end, or you can leave fuel as-is to run clean on the low end but run lean at the high end.  That's the basic problem.  You can add or remove fuel everywhere, but no adjustability in between.  Your 77 doesn't even have an O2 sensor.

 

Besides that $1000 won't get you far.  The small stuff will eat it up.  Make a detailed list of everything you'll need,  including gaskets, sealant, new studs, etc,. just for the head work and the actual installation and see if you can even do that for under $1000.

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On the other hand, you could just do it and if it don't work well, go ahead to Megasquirt or similar.

 

As far as basic power gainers, most say a better exhaust system and head work are the two biggies.  There are many threads out there that started with your same question.  There's probably even a thread in the FAQ's.  Check the L Series forum at the top.

 

http://forums.hybridz.org/forum/90-l-series/

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I understand the issue with bad roads.  It is hard to say if you can find a middle-ground for suspension because everyone's tastes are different.  A decent set of sport springs with new shocks will probably not be as stiff as getting a full coilover kit, but it still may be stiffer than you want.  As for ride height, there are some lowering springs that only drop the car about an inch or so, and in some cases people have put lowering springs on their cars and actually GAINED height because their old factory springs were worn out and sagging so bad.  This could very well be the case for your car as well, but it might not.  If your springs struts are old and worn, replacing them for just some new stock replacements could also make a world of difference.

 

NewZed did a nice job of explaining the factory ECU's inherent problem with modification.  For a daily driver like yours, it is not really possible to gain any real power while retaining the factory ECU, especially for only $1000.  Not to say it is not possible at all, but gaining a bit more power on the high end as NewZed explained, will make the engine run very rich throughout the rest of the RPM range which will definitely make it less pleasant for the daily drive (mpg will suffer, you will probably get a pretty strong smell of gas from the exhaust, etc.).  The other side of things (running clean down low and lean up top) is not good either.  Running lean raises cylinder temperatures and can result in pre-detonation which can destroy a motor, and will burn your valves up as well.

 

Doing a rebuild of the top end may be able to gain back some HP that the motor has lost over the years, so that may be worth it.  If you do a lot of the work yourself and shop around for parts, you can do it for quite cheap.  Definitely look through the L Series forum as NewZed suggested.  There are lots of good ideas in there.  The big thing to ask yourself is what is more important to you: a comfortable daily driver, or something with a bit more power?  Not that you cant have both, but you will need to spend quite a bit more than $1000 to do so.

 

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