26 replies to this topic

[Davey G]

Since the 280Z is fuel injected I want some help with knowing how far I can go with the stock EFI engine. As the paint and suspension work are finishing up I'm wishing to formulate some engine upgrade strategies for street performance in phases. Mr. Cerutti's 280 mods is on the far end of my thinking (and pocketbook) - computer programmed 280 ZXT, raced out suspension, etc., so that might be considered a Phase 4 with an EFI engine (might decide on carburetors before that point). That said, what would be Phase 1 with the stock engine? My inexperienced thinking says K&N intake, 6-into-1 headers, 2.5" exhaust, electric engine fan, etc. Then at Phase 2 (rebuild time) perhaps a lighter flywheel, higher flowing oil pump, bigger AFM, etc.

Thoughts, opinions?

[ThreeMoneyJ]

It's good that you have realistic goals for what you want out of your car. Street oriented performance is an obtainable goal. IMO that means reliability, which is what I would aim for.

Do you have a price range and budget in mind? If you don't yet, then set a budget and try to stick to it =)

I would do modifications that you can build upon. An example of this would be some sort of engine control (EMS). This would allow you to get the most out of any future mods.

With that being said, an intake and exhaust are also good mods to build on, and will probably give you more gratification (you can hear and see them!) The stock EFI system is hampered and cluttered by a restrictive air box, AFM, and small throttle body. IMO one of the best ways to clean/clear up that problem is with......... you guessed it, aftermarket EMS!

[Drax240z]

IMHO, stage 1 should be brakes and suspension. 280zx stock system isn't as lacking as the 240-280z though. Some good pads are a nice starting point.

Great bang for the buck, if you don't do a lot of highway miles is change your diff ratio. Going form a 3.90 to a 4.11:1 will transform your car for just a few hundred bucks.

[Orangy]

Sounds like a good plan! I remember seeing something here on Hybrid Z about using a Toyota Cressida MAF. Has a whole step-by-step process of putting the Nissan electronics in the Toyota MAF. That and the K&N intake is a good idea(especially doing both at the same time), so is upgrading the exhaust. MSA has an electric water pump you might want to look into getting to free up a couple horses.


http://www.atlanticz...rade/index.html is the link that shows how to adapt the Toyota MAF to use in a Z.

[Davey G]

Thanks for the guidance everyone! I will formulate a plan and proceed.

Davey G

[Davey G]

I have an exhaust leak where the exhaust manifold joins the downpipe (bad donut?). Headers are part of my future mods, and will get the 2.5" exhaust at the same time. Will the combination buy me anything, or do I have to switch to a MAS and larger throttle body to gain anything? Just wondering how to prioritize the mods. I'll probably upgrade the sway bars to 1" front, 7/8" rear soon. I've also finished interior refurb (except the cabin light), carpet, and polished out the paint in the meantime. The car also runs great since replacing the AFM-to-throttle body boot. New connectors for the injectors soon also.

Edited by Davey G, 07 September 2010 - 11:15 AM.

[sticky280zx]

ive done alot of "packages" for people over the years and heres one that theyre always happy with

header
exhaust
intake
bigger 60mm 240sx tb (with spacer)
aftermarket barbed fuel rail with gauge
adjustable fuel pressure regulator
Ported intake manifold (gasket matched runners/openeded up tb opening)
and a few tips and tricks that i tell them, that normally gets plenty of umph out of the MOTOR...but theres so much more involved with a car than just the motor.

Like others have said brakes and suspension should be FIRST (not much use having a faster car that you cant control)...also along with that goes drivetrain. Again a higher Diff ratio will make it zippy (going from 3.54 to a 3.9 or 4.11) also welding those higher geared diffs or buying the LSD equivilant will make a world of difference geting that newly added power to the ground. Not to mention with more power you could probably use a nicer stiffer clutch like the "dual friction" from centerforce or something similar, also while youre at it a lightweight flywheel will make a world of difference and let you pass people on the highway/city without having to downshift. And finally i would say look at your timing, ofcourse with that goes better fuel/spark. Instead of the cheap 87 you can run 93, advance your timing on idle and full vac, gap your plugs less or get a step hotter to make sure that fuel is burnt, also upgrading to the later zx distributor will make those higher rpms alot smoother.



Thats alot of secrets right there, alot of people know about the "parts" but its the combination and how you use those "parts" that really net the results. Its not just ill take one of everything and throw it on the car cause obviously if you ad a bigger exhaust but no more than stock air flow...you just wasted your money and arent going to see results.

Just look around on this site and others as there are a TON of write-ups on everything i have mentioned and then some that can make your Z alot more enjoyable on the street.

-Jeff

Just noticed you were in houston, so if you need any parts or interested in doing some upgrades just let me know as i am fairly close and can hook you up.

Edited by sticky280zx, 07 September 2010 - 11:49 AM.

[Challenger]

There's nothing wrong with the stock tb. I wouldn't bother with the electric fan, water pump, etc. You'll be getting alot more bang for the buck if you just get it running perfect in it's stock condition. As drax said check into a different rear end ratio but before anything make sure everything is working as it was designed. Brakes, suspension, get those addressed before anything else.

Before you do anything do alot of reading here to see what actually works. There are so many rumors and performance tips passed along that have no merit.

Edited by Challenger, 07 September 2010 - 11:56 AM.

[sticky280zx]

nothing wrong with the stock tb at all but for only 50$ or less to get the bigger tb and spacer along with porting the intake manifold it makes a big difference on drivability. I know that driving around town is alot easier and less shifting because it responds/flows easier than the stock tb. Also you dont have to have the throttle wide open to get the car moving...you can have it 3/4 and itll get up and go just fine. One thing about the stock fan setup is it can mess up your water pump, and be loud as hell...i dont think those are performance mods but i would think that the electric fan will cool better as well as provide alot quiter ride, or atleast let you hear that header/exhaust more

[Challenger]

Having full throttle at a much smaller petal input is not my idea of drivability. Throttle control and being able to make small changes is my idea of drivable. I assume you used the stock linkage? Also I think 50 is conservative for the costs. Generally a 60mm tb if you can't get it at a jy will be 30-40 or so with shipping. Doesn't seem like the original poster will be making his own spacer which is gonna put the price up a lot more.. Seems like alot of work for benefits I don't see. I might do it down the road so I can convert to cable which will help with drivability, it looks alot cleaner and silicone tubing is a little easier to find for the 60mm.

[FlatBlack]

Having full throttle at a much smaller petal input is not my idea of drivability.

Do you have a 60mm TB on your car? I don't think my 240SX TB is any hindrance whatsoever to the driveablilty of my car. However, I wouldn't suggest doing it to a stock car. I think that's a waste of money, especially if you are going to use the stock linkage. I did it to convert to cable throttle and have an input for MegaSquirt.

I would suggest getting new springs/struts/bushings before anything else [besides regular maintenance, obviously].

Edited by FlatBlack, 07 September 2010 - 02:04 PM.

[Challenger]

I don't, I suppose I shouldn't be talking then. Haha. I can't say whether or not it actually hinders drivability but the concept of having more throttle at a smaller pedal input still doesn't register with me as a benefit. Especially with the stock linkage which opens quickly already given the linkage geometry.

Matt did you ever drive it without the cable throttle? If not, I think you have eliminated the original problem. Doesn't the 240sx tb have a pulley that changes radius as you apply more throttle? In turn changing the rate at which the tb opens with respect to pushing the pedal.

[palauoriginal]

just get it running right
these cars are awesome anyways

wheels and tires would be the best first mod
the rest of the mods are a little more demanding
as soon as you start modding one part of the car
that mod leads to the next to get it running properly and in-sync (imo)

if i were to redo my car it would be in packages like this

1. wheels/tires/brake pads
2. engine work/engine management
3 suspension/frame work/diff

exhaust is good too throw in there

[FlatBlack]

Mat did you ever drive it without the cable throttle? If not, I think you have eliminated the original problem. Doesn't the 240sx tb have a pulley that changes radius as you apply more throttle? In turn changing the rate at which the tb opens with respect to pushing the pedal.

Good call, I didn't think about that. I never drove it with the stock linkage, I had about 1" of slop in my linkage and I wanted to fully shave my manifold as well as have a 'crisp' throttle.

If you don't port the intake to match the TB, low throttle open % is super choppy, so definitely do that.

[cockerstar]

This is usually what I suggest to my honda friends when they ask me what they should do to their cars. I think it's a pretty reasonable list for a fun daily driver that will make the car feel more "yours" and fun to drive. That being said, my suggestion for a project car will differ greatly
It sounds like you're just looking for a fun car to drive, rather than something that's barely streetable, which is where I'm heading with things.

Cockerstar's 5 step system to having a fun daily driver:

1. Intake and exhaust - typical K&N filter, headers, and 2.5" or 3" all the way back to a straight through muffler.
2. Ride height - can range anywhere from full coilover conversions, but lowering springs and shocks are a more affordable route.
3. Sound system - I'm simple here! A good head unit, some components and a single 12" sub will keep me content all day long.
4. Wheels - It's your car, pick what you like the looks of.
5. Tint - if your paint and body work are already in good shape a mild window tinting will pull the look of the car together, imo.


Then again, not too much of that "phased plan" is performance oriented, but I've had many people be quite happy with it.


Personally, I'm going through and doing a complete suspension overhaul on my car before I do anything else. Lowering springs, adjustable shocks, big brakes, limited slip with a more aggressive ratio, poly bushings, etc. I've chosen to keep it pretty mild since the car will mostly be used for street driving.

Cconverting to a standalone EMS (megasquirt seems to be a favorite) will let you get the most out of the stock engine, and take advantage of whatever other modifications you do in the future.

Set a goal for the car and then go from there!

[jbehuniak]

The intake and exhaust is a good idea, you can make the AFM a little rich and advance the ignition (run premium gas) The lightweight flywheel isn't necessary but you get the new clutch also and it makes a huge difference. It might be easier to stall but thats if you cant drive stick. But everything thats said above are some great things to do to your Z, but if you get your baseline high then everything that you do after will be that much better. If the car has good compression, valves are in adjustment, injectors are working as they should and ignition system is strong then do the next steps to your car.

[Davey G]

The intake and exhaust is a good idea, you can make the AFM a little rich and advance the ignition (run premium gas) The lightweight flywheel isn't necessary but you get the new clutch also and it makes a huge difference. It might be easier to stall but thats if you cant drive stick. But everything thats said above are some great things to do to your Z, but if you get your baseline high then everything that you do after will be that much better. If the car has good compression, valves are in adjustment, injectors are working as they should and ignition system is strong then do the next steps to your car.

Guys

The suspension part is done, including bushings, no vibration even at speed. I replaced the AFM-to-TB boot since it was old and cracked, had the AFM adjusted and timing set - made a huge difference in the engine's ability to climb thru the RPMs. Runs well all the way past 90 mph, though slower getting there than I'd like. The brakes are done, albeit stock. Replaced bushings on shifter, new carpet, new vinyl, new tach. I get about 21 mpg with freeway/town driving, everyday driver.

What size wheels/tires work well for street performance? I have some 15" alloys with Michelin 60-Hs on it now. Good tires but probably not the profile I eventually want.

I also have an exhaust leak at the donut joining manifold to downpipe. Is it time for those headers, or just get that fixed?

Davey G

[palauoriginal]

headers can increase engine noise unless you want that. there isn't really a big big increase on performance unless your engine is modded otherwise. i'd say just get an nice 2.5" exhaust done.. Borla mufflers sound good on the L series imo.

your wheel/tire combo is probably fine for now. I would save for the 16x8 xxr's or something similar.

[sticky280zx]

well the 15's would be fine, if you go down to a 50 series sidewall itll pick up the lower gears quicker, and handle better, but also add rpms on the highway so its definately a trade off.

I would go ahead and get the header, and exhaust at the same time, if anything you should shave some weight with aftermarket vs. the HEAVYYY stock.

If i were you id get my shocks/springs next and swaybars as well.

and id ditch those stock bumpers if i were you, itll make it quicker by saving you alot of weight. and look better, best part is....its free =)

Edited by sticky280zx, 23 September 2010 - 01:42 PM.

[280zx 2by2]

headers can increase engine noise unless you want that.

A header won't necessarily increase engine noise by itself. An exhaust system will. (By engine noise I assuming you mean exhaust dB? Because as far as engine bay and passenger compartment there was virtually no difference except for a change in tone when I installed mine.)