Looking for insight! L28 N/A Build

[James51]

Hi guys,

 

I'm looking at purchasing a 240z which has an L28 swap. The owner has done quite a bit of work to the block but due to his area never had chance to have it on a Dyno for some real tuning. He doesn't know what it's putting out currently but I'd like to get an idea of it's potential that I could expect if I had it put on a dyno with a decent tuner. Also to this point, can anyone suggest a good L series tuner on the Gold Coast / Brisbane area? It is N/A so I was guessing I'd be optimistic for 200-250hp at the wheels?

 

Below are the specs he has provided me on the engine;

 

F54 block - Bored 40 thou tanked and surfaced. New welsh plugs, new crank bearings, new flat top forged pistons

N42 head - Ported beadblasted & polished

New intake and exhaust valves, springs and valve caps (no specs on these at the moment)

Mild cams (no specs currently) and reconditioned distributor graphted to match the cam.

Pair of 32/36 Downdraft Webber carbies

Extractors into 2 1/4" exhaust

R180 3.9 Dif

280ZX 5 Speed Gearbox

 

Other items that are more general maintenance and reliability;

Adjustable timing kit

New water pump

 

I know that there's some variables here, as N/A will greatly differ off how aggressive the cams are and I don't have specs, but if anyone could give me a ballpark / confirm my thoughts would be greatly appreciated!

[1600dave]

I'd be optimistic for 200-250hp at the wheels?

 

Extremely optimistic, I would say.

 

Till you get the specs of cams / porting / valve sizes / etc / etc to prove otherwise, it sounds to me like a fairly standard engine with a mild cam and port job.

[dat2kman]

A pair of 32/36 downdrafts?

Get rid of those for a start.

Set of stocko Hitachi units, rounded tops, or a set of pommy SU's in 2"

Next up, a set of triple sidedrafts, on a 28 bored at 40th, 42's or 45's, but choked down to get good air velocity through the carbs.

[James51]

Hah Ok. Yeah, that was an extremely optimistic guess as that's about the top for an N/A l28 right?

 

I'll admit I'm a young bloke, I know a bit more about Fuel injected forced induction engines than the N/A Carbies, but I'm learning!

[benny]

i would say more like 130-150 atw

[James51]

Thanks for the guestimate. That's the kind of answer I was looking for.

 

So the opinion is that those carbies are the restriction/bottleneck here (and maybe the cams?) I come from the 2J world where once you go forged, the sky is the limit.

 

He's selling it with an L28 fuel injected and 'aggressive' cam spare engine, so I may have some stuff to work with here before looking at an engine swap.

[benny]

if your after cheap power slap a turbo on the side... getting that sort of power NA is going to cost you some big coin

 

 

also remember that the zed is fairly light compared to modern jap cars so you may not need as much power as usual

[James51]

Yeah, FI is always a relatively cheap way of making power. I think eventually I'd look at a 1JZ conversion - a base I'm familiar with. The power to weight is definitely a lot different when compared to a Mk4 supra weighing in at close to 1500KG.

 

The reason I'm most interested in this car is because it has brake and suspension upgrades galore, so it's the perfect base for a future engine conversion. But I'd be planning to run with the L28 for a while yet.

[Scoota G]

Remember there's a combination of elements that makes a fast car, if you're driving a Zed, 90% of other people you will beat with the vehicle motionless (and the right stance). It's not about power unless you plan to do some track work, but then again if you come from that 2JZ world stick with it. I must be one of only a few guys who's put a Cleveland in a Zed, LS1 and RB conversions are popular. I admire someone who takes the path least travelled.

[luvemfast]

i would say more like 130-150 atw

Not even close!

 

You also say the heads been ported. Any flow figures?

Because there's porting...... And there's PORTING!

 

To give you an idea.

My L28 is bored 3mm over, PORTED!, forged domed pistons, long rods, pretty big cam, good headers, 2.5" exhaust, modified dizzy, triple 44PHH Mikuni's and so on.

I've got 146 rear wheel kW's. There's more with exhaust and cam upgrades.

 

But estimate the set up you're talking about to be 80-100kW's. (Being generous)

You're a young bloke? If you get 110kW's in a Z, you'll have a blast. Do brakes and suspension first.

[benny]

Not even close!

 

You also say the heads been ported. Any flow figures?

Because there's porting...... And there's PORTING!

 

To give you an idea.

My L28 is bored 3mm over, PORTED!, forged domed pistons, long rods, pretty big cam, good headers, 2.5" exhaust, modified dizzy, triple 44PHH Mikuni's and so on.

I've got 146 rear wheel kW's. There's more with exhaust and cam upgrades.

 

But estimate the set up you're talking about to be 80-100kW's. (Being generous)

You're a young bloke? If you get 110kW's in a Z, you'll have a blast. Do brakes and suspension first.

 

 

i was talking hp not kw

[zzzzed]

Has to be more than 80 rwkw. My 100% stock  full pollution gear 100 years since last tune l26 got 80rwkw

[Agno]

Mine dynoed at 99.4 rwkw a couple of months back on a stock motor with 2.5" exhaust and triple 40s

[PZG302]

To put all the power figures in perspective, one operator asked me what power would you like your engine to have?

Realistically, with those mods you will have a little over standard for an l28.

 

Ask those who have good engines what it cost them to get where they are in power. My last l28 was measured at 198rwhp on the dyno. Quick specs for my old motor where 3mm overview, 133mm rods, custom pistons to replace the Mitsubishi pistons that were broken, and now used as ashtrays and paper weights. N42 head with a lot of work to porting and some to the chambers, hard to get manifold, custom extractors and using n47 injection manifold with haltech f9 computer and electronic dizzy. Cost was around $8k last rebuild when taking out some extras that needed to be done.

 

There are other motors out there with more power than mine, but will have cost a lot more to achieve that. I have no idea what the true cost of my motor was as it was built for me as part of my sponsorship deal with a workshop when I raced in Sydney, but 20odd years ago would have been around the $6k mark easily using the old adage of $1000 per pot for a reasonable motor.

 

If you want to go fast use the bolt in cheap power from another motor option and don't worry about the l series motor unless you want to keep everything original.

[d3c0y]

Seems like an odd engine to put forged pistons in, with everything else being so mild. We are all just guessing so what's the point? Take it to the dyno and it does what it does, these cars go pretty fast with not much power.1JZ is very hard compared to throwing an RB25 in it.

[C.A.R.]

Actually, a rear bowl 1JZ is easier than a RB.

No sump & pickup mods with the Toyota motor...

[James51]

Thanks for all the replies everyone. Either way the power to weight will certainly make it feel faster than a Camry with 90KW - Maybe not the straight line that the Supra has, but the main reason for me looking at this Z in particular is the fact it has 6 pot Wilwood fronts, 280z rear discs, eibach springs, KYB struts and polyurethane bushes throughout and looks as rust free as you can expect a Z.

 

I do the occasional track day here and there, but other than commuting most of my driving time is spent around the mountains - so good handling was at the top of the list. 

 

I had heard that the 1JZs are an easier swap as long as you get the rear sump. Something about stock/2JZ engine mounts and a new crossmember?

[d3c0y]

Actually, a rear bowl 1JZ is easier than a RB.

No sump & pickup mods with the Toyota motor...

 

 

Yeah but clutch and exhaust are on the wrong side and the mounts are harder. No off the shelf mounting kits either. Easy for you when you are a welder