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Post by justin on May 20, 2005 12:54:27 GMT 11
Gee and I thought my plate was flash ;D J
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Post by namic69 on Jul 14, 2005 21:27:58 GMT 11
Well I put my 96 Bighorn on the dyno today and here are the results.... First the mods...
2.5'' exhaust back to turbo, K&N air filter, ERG valves disconnected, X1R to oil, Boost compensator = 12-13 PSI boost
Run 1 with above only = Peak Torque = 363Nm@ 80.6km/h Peak Power = 61.5Kw @ 102.1km/h
Run 2 with LPG fumigation = Peak Torque = 427.8 Nm @ 67.6km/h Peak power = 73.7Kw @ 96.8 km/h.
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mars
Isuzu Baby
Posts: 4
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Post by mars on Jul 15, 2005 2:58:18 GMT 11
hi
how did you do the lpg conversion and is it much lighter on diesel
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Post by namic69 on Jul 16, 2005 16:26:05 GMT 11
Well I had my 3.1 Bighorn on the dyno and results are their to see, not so sure about the torque readings for yours tho... I must add that I did not notice much of an improvement after the 2.5 exhaust
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Post by namic69 on Jul 16, 2005 16:28:03 GMT 11
Just a basic BBQ bottle and regulator a tap to adjust flow straight to the iar box. The bottle was on the floor in the back seat.
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Post by namic69 on Jul 16, 2005 16:30:01 GMT 11
I am only playing with the idea so I am not running it all the time. Tho it stands to reason that with an average of 20% more power you should be a little lighter on the pedal...
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Post by mudgrip4 on Jul 17, 2005 23:19:11 GMT 11
Hi Namic - there is something seriously amiss with the kw figure from your dynotune test. The standard 1996 3.1 new generation intercooled motor produces 99kw at the flywheel and 294nm of torque. You lose approx 25% if measuring at the back wheels. So your isuzu standard should read about 74kw, if dyno assessment is taken at back wheels as usual. Not 61.5kw or 73kw after lpg fumigation. This is far too low.
If you have a 2.5" bigbore, K&N filter, and boost compensator(whatever that is) and it is boosting to a healthy 12-13 lbs, I would expect your vehicle to produce more - not less kw - than standard specs. Your first torque reading of 363nm sounds just possible given the mods you have made - it is a 20% increase in power from the 294nm standard. But one would also expect a healthy kw increase over standard - perhaps also of 10-20% to about 110 - 120kw at the flywheel, or 82 - 90kw at the rear wheels where your dyno measurement was taken.
Kw would certainly not decrease to 61.5 at the rear wheels - this figure is not right. Even if yours is the earlier model 3.1 motor with 92kw and 275nm of torque, it should still read around 69kw at the rear wheels when stock standard, and improve considerably on this with your mods.
My 2.8 bighorn with similar mods to yours plus significant fuel delivery increase and advanced fuel pump timing produces 340nm of torque (up from standard 225nm) and now measures 89kw at the rear wheels - giving about 118kw or 157hp now at the flywheel (compared with 110hp or 81kw standard.)
This is from a top specialist and a well calibrated machine - within 1kw of factory specs for new machines. However, not all dynometers are this accurate. You should have significant kw gains if your torque figure is up - not decreases - so I would look again at your figures as something doesn't fit here. Mike
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Post by Graham on Jul 18, 2005 1:12:26 GMT 11
Mike's right about one thing - not all dynos are calibrated the same, nor do the operators use them with the same methods.
From my experiences, you should never compare dyno readings from one place with those from another. The only way a dyno should be used off the showroom floor, is to determine the difference made by a modification, or a 'dyno shootout' measuring different cars on the same dyno and under the same conditions (air pressure, temperature,etc).
The important thing to note is the power increase with the LPG! That's impressive for a hose shoved in after the air filter!
If you want to compare two cars for engine performance, put them on the drag strip - but then, if someones running big tyres, that will throw a 1/4 mile time anyway.
Cheers! Graham.
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Post by geeves on Jul 18, 2005 19:01:30 GMT 11
Looking back at the results thoughs anouther question. The measurements are at a set kph What gear was the car in and how many revs. The 3.1 hits max power at about 3600rpm. With lpg I would expect this to be slightly higher as well although its not wise to run a diesel much faster than this
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Post by namic69 on Jul 18, 2005 19:10:59 GMT 11
Thanks Mike and Graham for your input, I was a little disappointed in the readings, I had looked on the net b4 buying my truck and compared the Toyota's Nissan's and Isuzu's and the rated 99.24kw was one of the reasons (and I already had an older Isuzu that was a beast) for getting it. I did my dyno check in Auckland at Shore Performance, any recommendations on some where else?
Still cannot go past the difference of power between the two, a friend of mine has a cruiser that he had on the dyno and it rated 98kw and now he has a intercooler but with LPG i am still close racing up the beach :-)
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Post by mudgrip4 on Jul 18, 2005 20:16:52 GMT 11
Namic - is yours a swb or lwb 96 bighorn, manual or auto? Being indirect injection and fairly heavy at 2090kgs, the lwb model will not be overly quick off the mark. Prados are often 200kgs lighter than this and the autos can be quicker off the mark to about 70 or so than the slow isuzu manual box.
Still something funny here. Your friend's cruiser showing 98kw on the dyno would have approx 130kw (or 25% extra) at the flywheel, which is very powerful - around 175hp. A brand new model Prado tweaked might just produce this. If you are anywhere near this in performance - esp given your weight - you will have alot more than 61 - 73kw at the rear wheels. It is possible the dyno shop may have factored in the wrong diff ratios - and as geeves notes - I can't quite see the reason for kph rather than rpm figures for max torque and kilowatts. Max torque is at about 22-2300rpm, max kw at least 1000rpm more. Do these revs match the kph speeds they give in any of your gears? What model exactly is your friends Toyota? What isuzu model did you previously own and how do they compare? Mike
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Post by namic69 on Jul 20, 2005 8:09:27 GMT 11
Mike, my truck is a lwb auto. My friends truck is the 95 VX cruiser 4.2ltr 24value diesel turbo 3" stainless exhaust, K&N air filter, ERG disconnected, 12psi boost, max allowable fuel increase and now a water to air intercooler (and front and rear dif locks :-( .) IT IS A BEAST.....
When he had his on the dyno they did the test in second gear only (done at Auckland 4x4). When mine was done the did it in drive and started test at 50kph and finished at 120kph. I don't know how to post copy of print out.
My old truck was a 94 lwb auto with the Lotus package, it was a good truck but the new one is much better, I just wish the new one was a Lotus too. Even stock their is a noticeable difference between the 94 and 96 models.
I am thinking of going out to Auckland 4x4 to do another dyno run.
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Post by namic69 on Jul 20, 2005 8:17:21 GMT 11
I am also not so sure about the Torque on Demand... On the road if I want to turn out of a side street on to a main one or if i'm on gravel it is great. 4WD'n im not so sure, the system waits for slip at the rear wheels before it responds and at 20m/seconds it is quick but i prefer full time 4wd off road
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Post by namic69 on Jul 20, 2005 8:35:47 GMT 11
Now I am rambling but....
My only major gripe about the truck is the EFI, I have not been able to find anyone able to increase fuel delivery.....
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Post by mudgrip4 on Jul 20, 2005 13:32:59 GMT 11
Hi Namic - a couple of points.
Your friends 1995 24 valve VX has 125kw (about 170hp) standard, and with all the mods you list for it - it could easily be 200 - 210hp. The 24 valve model pulls very well even standard and if your lwb isuzu is anywhere near this modified vehicle on the beach, you have a quick isuzu. VX = 2280kgs, isuzu = 2090kgs - not overly much difference.
This performance comparison suggests you have in fact a very good kw rating for a 3.1. And given this, frankly I wouldn't bother with more $$ and more dyno testing - at least until you find one sometime which is proven accurate.
Enjoy your vehicle - obviously it pulls rather well. The earlier dyno figures of 61 - 73kw are due to either technician error, or a crap machine. Have fun. Mike
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Post by geeves on Jul 20, 2005 14:48:01 GMT 11
I think Mudgrips hit this on the head As your was tested in drive it probably never got over 3000rpm which makes these figures quite impressive It would be nice to know the true output at peak revs but we know this figure is likely to be as good as it gets so does it realy matter.
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Post by namic69 on Jul 20, 2005 15:33:36 GMT 11
Well the main reason for the dyno was to get on paper the differences with and without LPG but also because I have not been able to run it up against other Bighorns. I have posted a few trips on the site for play sessions up the beach and half a dozen m8s have turned up for a play but no one from Clu Isuzu, in fact I have not bothered posting the last two trips.....
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Post by namic69 on Aug 10, 2005 20:03:37 GMT 11
Well I could not help myself so I went and got another dyno reading done, this time at Auckland 4x4 where my friends vx cruiser was done and .....
Damn the readings were so close to the first test it was not funny...... this time tested in second gear with the transmission set to power.....
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Post by mulover on Aug 13, 2005 17:45:51 GMT 11
Hey james w, when you do your exhaust ged rid of everything from the turbo back, especially those warm-up things, i when 3" all the way through, with straight through muffler, even made a custom piece to fit around the oil filter on my 2.8, and i have never looked back.
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