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Standard L28 Power Figures


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Has anybody got some dyno figures on a standard L28 with stock cam. I'm just curious at what rpm the power drop off at? Please feel free to comment just based on driving your L28 and were it feels as though is the upper limit of producing any more power?

 

Sulio

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With mine on injectionand a 76 degree cam the power falls away at about 65-6600 rpm. I use a max of 6800 by the tacho, probably about 7200. That's where the motor changes note to the horrible scream that says go up a gear.

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Thanks guys. Demitri I meant more in terms of power limit in respect to revs as I'm  getting good power all the way through until hits 5000 where the engine will rev but no more significant power gains. I've got pretty small (130) main jets so I think going bigger main jets (145) will get me that more power to the 6000rpm ish range. Anyhow just wanted to see what a stocky will do on SU's as I can't recall what it was like on the SU's?

 

I'm hoping to have my AFR gauge sorted and O2 sensor installed this weekend to check on mixtures through out entire rev range and make sure I don't over jet it in my quest for more power!

 

Sulio

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sorry, forgot to say I never really gave that engine a good rev. From memory, after about 5500 - 6000 it was painfully obvious power had fallen off. Good strong torque from around 3k to about 5ish. The triples do so much! With the efi, there was no jetting to worry about so the power figures I was getting I think was as much as you could get from a stock L28. Also my TB's are equivalent to 50mm Webers.

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They're the revs I would expect for a stock cam, good torque and power from 3-5. A bigger cam will raise the revs at which the power drops off, but then your torque curve gets peakier and comes in higher. A good torquey motor will always blow away a peaky motor in the real world.

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They're the revs I would expect for a stock cam, good torque and power from 3-5. A bigger cam will raise the revs at which the power drops off, but then your torque curve gets peakier and comes in higher. A good torquey motor will always blow away a peaky motor in the real world.

 

My plan is to go to a mild cam at a later stage. An increase and shift in the power curve by 500 or 1000 rpm would still be ok as it drives very good down low at the moment which works pretty good with stock ratios and 280 box.

 

I won't do anything further re jetting until I get some AFR figures hopefully this weekend but I reckon my main jet will most likely be a little undersized so if thats the case maybe I'll be able to squeeze a little bit more out at the top.

 

Sulio

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Guys

 

If you are after a fresh cam give Camtech a call or check out their site

http://www.camtechcams.com.au/........ they have billets in stock (not reground standard cams). So they fit with no modification to lash pad heights or rocker wipe (if your head still standard.

Tighe in QLD are out of stock of L6 cam billets and they are on back order (as with Wades etc)

 

Sulio

the only accurate method to assess mixture and power/performance is to run the car on the chassis dyno.

 

You can get very reasonable dyno tuning rates (half the price of Power Play) with proven results from Lou Mondello in Moorabbin (9555 9591).

The last Zed he did (L28 with triple dellortos "expertly" set up by the Zshop.....pwfft!) went in making less than 90 rwkw and came out with 120+ rwkw after some carefull mixture and cam and ignition timing adjustments...........needless to say the owner was stoked !! 

 

 

cheers

Alan

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Hi Alan,

 

My plan is to rebuild this engine when my house extension/garage is finished and this is the reason I have been holding out re dyno tuning. As a result I have been learning alot on how the car is running re the carbs I've installed and continue to do so. The AFM reader I'll install next week will also be part of that learning curve.

 

Once I finish the rebuild yes then it will be a good idea to have it properly tuned but even then it will only be once I've thoroughly given it my all as far as research and my own adjustments go. Only at that point will it be very interesting to get it on a rolling road and tune it.

 

In the mean time it would be a good idea to have a dyno day for some of the Z guys here. I'm just waiting on Ash to get me some numbers on price based on numbers attending but that another thread that is currently active on this forum.

 

It would be nice to get 160HP at the wheels with current set up, I really need to jump in a Z thats doing about 200HP at the wheels to get some benchmark feeling.

 

Sulio

 

EDIT: Alan, did you get the dyno sheet since your rebuild? I did your informative thread re your rebuild, it sounds like you got exactly what you wanted re your cam selection, will be looking at same supplier when that time comes.

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...

It would be nice to get 160HP at the wheels with current set up, I really need to jump in a Z thats doing about 200HP at the wheels to get some benchmark feeling.

...

 

Dont we all !! Purely for that benchmark feeling ...  :P

 

What AFM monitoring doodad did you go for ?

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Well I'm not sure if 160rwhp is being unrealistic based on the current set up, L28 with elec dizzy, headers and 40mm tripples but that why I'm posting this thread.

 

As far as the AFR meter goes I bought an LSM-11 aftermarket Bosch O2 sensor and waiting for gauge from Jaycar:

 

http://www.techedge.com.au/vehicle/wbo2/5300.htm

 

Sulio

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dont we all :  regarding sitting in a 200 hp datsun for "benchmarking" not your power goal which you should get close to.

 

Hell if my stocko l24 with piston blowby and valve leakage  can do 105hp on triples and stock exhaust... you'll get close to your goal methinks.

 

Thanks for the link to the AFM.

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oh yes I see Modular, yer I don't think 160HP is too unrealistic from what I've read but another thing that starting to look clearer is stock L28 cam might actually peak at about 5000rpm so my current set up might well be limited by the cam but as i said will push on next week.

 

EDIT:

 

after reading the post below I think my figure of 160 at the wheels is unrealistic with the current motor set up. 140 would be more realistic.

 

http://forums.hybridz.org/showthread.php?t=92888&highlight=l28+curve

 

Sulio

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200hp at the wheels is pretty unrealistic for the set up your looking at unless you have big dollars.

 

One of the guys up here in Brisbane running an SC 280Z gets 196 rwhp on his L28 with injection. He has spent a lot of money on cranks, rods pistons, inlet manifolds, etc etc, about $15k to get there.

 

My race motor, L28 bored to give me 2.9 litre capacity with P90 head, ports cleaned up to match standrd manifold, that has also been cleaned up, electronic dizzy and big 76 degree cam get just under 150rwhp.

 

The big advantage of my motor is the torque, a very flat torque curve showing between 650 and 700 lb on the dyno dynamics dyno sheet between 3200 and 5200rpm. Peak power is at around 6200 rpm.

 

I could chase the magic 200rwhp, but don't have the budget for that type of expensive motor, and I feel there are better gains in track times by chasing the handling in the car.

 

Plus all dynos can be tweaked to give you figure you want to read, and some unscrupuless operators will tune the dyno rather than the car to give the power figures you want to see.

 

In reality the only true dyno is the stop watch. I have had my car on two different dynos, the second run with new leads, dizzy cap and better inlet piping, less restrictions showed 20 hp less and in better conditions, ie cooler weather.

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Sulio

 

My final dyno results were pretty much spot on with what I expected with the L26 refresh (111+ rwkw or approx 145hp) given the comp ratio, cylinder head clean up and cam selection (Camtech 712 grind approx 70/30)

 

Any respectable L28 on triples should comfortably make 125 rwkw (164 hp) if built correctly.

(even my L24 powered 240z race car was making 135+rwkw on triple 44mm Mikuni Solexs) Most L28 powered Zeds competing in the sprint rounds are up around the 135 - 140 rwkw.(185hp)

Squeezing any more power out of an L28 is an exercise in ever diminishing returns.......the more $$$ you spent you get incrementally less HP gain the closer you get to the 200 rwhp (150+ kw) and beyond.

 

On the subject of dyno results , I agree the dyno results should only be used as baseline for your own vehicle and it is near impossible to compare dyno results from different operators.

However I have had my Roadster on three different dynos, AVO, Power Play (ex- Datrally) and the one I use now at Allcraft and they are all within +/- 3 kw's of each other.

 

cheers

 

Alan

 

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Plus all dynos can be tweaked to give you figure you want to read, and some unscrupuless operators will tune the dyno rather than the car to give the power figures you want to see.

 

 

This is so true. heard of it and seen it. in particular at the dyno shootouts u can notice the fudges.

 

anyway hence i dont trust any of them. been in the industry far too long and seen all the crap that has been going around. hence my car never sees dynos anymore. check it against all the stuff i got and if it feel and sounds good its good. i know of cars that had aperently 50kw at the wheels more than my car but i still fly past them. hmm strange i thought more power = faster at least in straight line.

 

only time i trust a dyno is if i own one and know how to  use it.

 

if u making an extension make some room for a dyno  ;D

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IMHO the figure to look at isnt the max power but the torque figures. When ever it see a dyno card i tend not to look at the max power I am too busy dissecting the torque curve.

 

That said 150 rwhp would be nice.

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200hp at the wheels is pretty unrealistic for the set up your looking at unless you have big dollars

 

PZG302, yer there seem to be so many variations on figures. As per the HybridZ thread I added on the first page there seem to be people that pull really good figures on fairly lightly modded motors whilst at the same time others that have spent alot more to only get a little more HP!? I'm not chasing numbers just eager to see what the motor will be making when I get a chance to put it on a Dyno. I think you might have misread my statement re 200HP, I would just like to go for a drive in a car running this just to get some sort of bench mark figure. Very ineteresting to get some info on those track Z's you run against.\, gives me further perspective.

 

Any respectable L28 on triples should comfortably make 125 rwkw (164 hp) if built correctly.

(even my L24 powered 240z race car was making 135+rwkw on triple 44mm Mikuni Solexs) Most L28 powered Zeds competing in the sprint rounds are up around the 135 - 140 rwkw.(185hp)

Squeezing any more power out of an L28 is an exercise in ever diminishing returns.......the more $$$ you spent you get incrementally less HP gain the closer you get to the 200 rwhp (150+ kw) and beyond.

 

I am not planning to blow too much money on the motor and when the time comes I'll be picking everyones brain here to get the most bang for my buck. I want to be realistic re brakes and suspension and my driving skills. I reckon best to improve on all of these before trying to go for significant power increases.

 

Some stock cam info I found, (I'll post it here for easy future ref for myself):

 

http://www.geocities.com/bruskiz/ZCamSpecs.htm

 

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  • 2 months later...

PZG302, yer there seem to be so many variations on figures. As per the HybridZ thread I added on the first page there seem to be people that pull really good figures on fairly lightly modded motors whilst at the same time others that have spent alot more to only get a little more HP!? I'm not chasing numbers just eager to see what the motor will be making when I get a chance to put it on a Dyno. I think you might have misread my statement re 200HP, I would just like to go for a drive in a car running this just to get some sort of bench mark figure. Very ineteresting to get some info on those track Z's you run against.\, gives me further perspective.

 

I am not planning to blow too much money on the motor and when the time comes I'll be picking everyones brain here to get the most bang for my buck. I want to be realistic re brakes and suspension and my driving skills. I reckon best to improve on all of these before trying to go for significant power increases.

 

Some stock cam info I found, (I'll post it here for easy future ref for myself):

 

http://www.geocities.com/bruskiz/ZCamSpecs.htm

 

 

 

I've got over 150RWKW and i can tell you it doesn't feel like enough at the moment!!!! Power delivery rather then peak power is far more important. I still have to change exhausts to get the proper power out of the car but just from experience having a strong power spread over a wide range is far more important then an end bragging right figure. Racings the only true test of speed.  ;)

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yes lets talk torque (punintended), hte area under the curve on a dyno sheet!!!

the more area, the better and more efficient motor.

power is a function of torque and roational speed, a cummins making 984 bhp @1800rpm is far more usable than a honda making 680hp @ 12,000rpm, and gues which one has a guarenteed operating life of over 10,000 hours???? yep not the honda!!! work that out in days... over 14 months straight!!!!

hond would be lucky to see 6 hours before it goes or needs to be stript down and overhauled.

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