engine upgrades

chris frizzell

chris frizzell

Club Member
hi all looking for some advice on engine upgrades my 280z it has a 280zx engine fitted and i would like to get some more power out if it without spending to much cash ( ian from yorkshire ). car engine is stock apart from a K&N air filter .it lowered with better shock and i think its got a LSD plus brake upgrade . at the moment its on its original factory exhurst . any recommended mod would be greatful as not sure whitch path to go down . ie slap a turbo on it of just mess with the cam, inlet and exhurst many thanks chris
 
AliK

AliK

Vehicle Dating Officer
Staff member
Club Member
Well buddy it all depends on your definition of "more power" and "not too much cash".

Cheap mods that had a noticeable difference on mine:

Magnecore racing HT leads
3 ohm Flamethrower coil
280zx electronic dizzy
Cleaning up all electrical contact points especially engine earth.
Z-therapy 240z SU carbs (do you have EFI? If so keep it that way!)
280zx internally regulated alternator.

You can always take the head off and port / polish yourself. What head do you have in yours?

If you want to spend more you could look at 6-2-1 exhaust headers and exhaust (Sean's or MSA are good or if you want to get fancy schmancy you can look at the fujitsubo regalis - but the latter out of the box won't fit around your diff)

My MSA header and 2.5" exhaust + "turbo" muffler is great but rather loud and proud.

More money?
Raise compression to around 10ish with flat top pistons, head gasket and a head skim/commensurate cam tower shim.

Wilder cam (I think yours is 248 duration!?) with more duration say 270 or 275 and more lift, but then you are looking at updated valve springs / seats etc too.

Tell us more about budget and power requirements.
 
Last edited:
jonbills

jonbills

Membership Secretary
Site Administrator
Hi Chris, that's a very hard question to answer. I don't believe the stock 280z injection system lends itself to much modification, so beyond making sure you've got all the power you should have, I don't think there are any cheap options - you're either looking at a switch to carbs or a replacement EMS before you can do modifications for more power.
But I might be wrong [emoji5] if you have a look around hybridz.org there might be some minor mods that the stock system can accommodate that pay dividends.
 
chris frizzell

chris frizzell

Club Member
hi its got the ht leads but not the coil and think its on standard dizzy also the alternator is brand new when i got it. i think i will do the head when its layed up next year but mr f said put a n47 head off a 280z .not to sure about the cams looks like a lot of hassel .mrf alos has a manefold and 2.5in exhaurst but in mild steel .Seans look great but pricey i was thinking of putting the headers on and having a ss exhaurst made .where can you get the coils in the uk i dont want the car to fast just a little more poke .the bloke from mzr gets 250bhp on the same engine as mine but he throws money at it .2k would be me. all the injection system has been reconned thanks for the pointers
 
johnymd

johnymd

Club Member
To get 250bhp you need to spend quite a bit of money on it. If you budget on £10k then you should be fine.

Here's a little breakdown of the cost of some of the bits:

Pistons - £1000
Rods - £300
Damper - £500
Bearings - £120
Cam kit - £1100
Flywheel - £350
Machining/ballanceing - £900
Headwork - £1000
Engine build - £1500
Exhaust/manifold - £1000
Inlet manifold - £550
Triple carbs - £1500
Electronic distributor - £200

This should see you in the 250bhp range. Personally I would then go EFI as that will probably only add around £1500 to the costs as you won't need the carbs.
 
Mr.F

Mr.F

Inactive
"mr f said put a n47 head off a 280z"

N42 head from early 280ZX to up compression with your late "flat" top pistons...
 
SeanDezart

SeanDezart

Well-Known Forum User
No pain - no gain - optimise the power that your engine in it's present state of tune can muster as Jonbills said using Ali's good advice. An MSA 6-3-2 is the best of the rest but still has (imho) restrictive primary pipes. Maybe have a looksee at my new S30 manifold coming in less expensive than the Street-Sport. Talking of which, when I get home, I'll post up a dyno graph from a Street-Sport fitted to a stock 280z so that you can see where the money goes.

I think JohnyMD's total figure is pessimistic - EFi at £3k plus rolling road set up...
 
AliK

AliK

Vehicle Dating Officer
Staff member
Club Member
SeanDezart said:
I think JohnyMD's total figure is pessimistic - EFi at £3k plus rolling road set up...
Click to expand...

I think John is pretty spot on with that lot and in the right ball park. To your point Sean, my RR setup after my next and final visit will have cost a total of £600 most of the time taken on SU needle re-profiling and mix optimisation. When I looked at triple OER DCOE carbs I made it closer to £2500 by the time you pay for import duties + setup/tuning + MJP airbox/filter + quality fuel pump/pressure regulator + new fuel rail and a few sundry items.

The immutable law of the universe be you a fighter pilot, astronaut or Z owner: going faster gets exponentially more expensive.

The first few ponies are relatively cheap and easy to gain but the last few ponies have a much higher, more eye watering GBP per hoof ratio!
 
SeanDezart

SeanDezart

Well-Known Forum User
So I would concentrate more on optimising the existing available power......and that means (and apparently you have them) lowered susp, front brake upgrade, LSD -perhaps aff a ligntened flywheel and check the stae of your clutch (upgrade ?) whilst there.

Surprising what an old Z will give on the roads with next to stock power when set up right.
 
chris frizzell

chris frizzell

Club Member
thank for the advice i think i will go with the minor mods ie maniflod and exhaurst need new anyway up grade the coil and poss the dizzy and have a talk with my bank manager about the rest .the cam and porting look like a possibility at a later date at the moment trying to get the car sprayed .a 3 week job is turning into 4months . hopfull its on the road for feb 2018 chris
 
Rob Gaskin

Rob Gaskin

Treasurer
Staff member
Site Administrator
I came to the conclusion about 10 years ago that spending a fortune on a car used on the road is wasted money.

All you need is enough power to 'see off' a Capri.
 
johnymd

johnymd

Club Member
I'd agree there Rob (says a man building a stroker!!!!!) that for a road car you just won't get many chances to enjoy it.

My blue car has always been an evolving project and the quest for more power is all part of the fun....and driving it fast round a track. The red car is a cheap 300hp lazy cruiser with great bang for buck. The silver rat car is a superb road car with its standard 2.4 and probably around 140hp. Perfect for a Sunday blast...… although I am trying to build a budget stroker for it that's already exceeded my budget and will be the most I've ever spent on HP. Engine conversions are the only way to cheap reliable power.

I'd just stick with the 2.8 you have as the quest for more power is a slippery slope.
 
johnymd

johnymd

Club Member
Just to add and thinking out loud. If you want to heavily restrict your budget and get the power up to maybe 200ish then what's required?

I know compression and cam generally go together and keeping under .5" cam lift would make the head less complicated. So with this in mind and if you could find yourself an n42 head. Then maybe the following could work:

2.8 block
Flat top cast pistons
Standard bottom end
N42 head with the standard larger valves
.5" mild cam
reasonable manifold and exhaust
su's
Get the engine properly balanced and use a lighter flywheel to lessen the need for a damper.
The rest of the engine standard.
Keep the revs below 6800

This is probably the best bang for your buck. This gets you to the point on the experiential cost curve where it starts to rise sharply so avoid going too much further than this. The only other thing I can think of would be to do a bit of porting yourself.
 
Alphabettispaghetti

Alphabettispaghetti

Club Member
It mounts up, but worth it. you could go for a 2.8 but thats just too easy. you can do a stroker for not much money as there are some cheap cranks knocking around. Do you really want all that boring torque though :)

depends what you want from an engine. There's something very appealing about having something just a little unique from the norm.
 
SeanDezart

SeanDezart

Well-Known Forum User
johnymd said:
… although I am trying to build a budget stroker for it that's already exceeded my budget and will be the most I've ever spent on HP. .
Click to expand...

Ah but the beauty and satisfaction of remaining true to the L-gata and heart of the car.....you know you have to try it - been there-done that !
 
richiep

richiep

Club Member
ITM in the US do them. Might find them on US eBay?

The ones in my FairladyZ’s L28 are 87mm flat top ITMs.
 
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