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Back from the dyno - Pt1

4K views 23 replies 10 participants last post by  Work Horse 
#1 ·
OK, just ran the XD on the dyno, i'm dissapointed but not without hope!

A major supply problem was found that is not due to the mixer. Thanks to all the places I've spent hundreds of dollars with so they cam blame the mixer and try to sell me a more expensive setup - idiots.

I managed a lazy 147rwkw @ 4900RPM with 2.4inHg vac and only 22deg total timing... but even at those RPM's I was running 14.9 A/F. After that the A/F is too high to continue making power, we shut it down @ 5200RPM still making 144kw but A/F is up to 15.3. The graph tells the story, 4200RPM i'm at a comfortable 13.2 A/F, at 4600 i'm at 14.4. The system just gives up!

He called a mate of his who runs an LPG parts place and he agreed completely... something is wrong well before the mixer. I'll have to look at replacing the lines, lock off's and converter before heading back there. Even then, we might find out with the A/F sorted out the mixer will restrict the system.

On another note, i'm very happy with the new cam, even if the hyd lifters not rattling has highlighted another unnerving rattle (NFI where its coming from either).
 
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#5 ·
Hey Greg,

What size gas line are you running? Single or Double?

It really sounds like convertor at this stage. Or a restriction before there.

How many lines from convertor to mixer?

Your running a complex mixer? Or Simple?
 
#6 ·
I often wonder if the lack of really powerful LPG cars is not due to the gas but due to the tuner's lack of skills in that area. Looking at all the troubles you have had greg, a competent tuner should know his job well enough to have picked it up ages ago.
You aren't the only one battling incompetence too... there are others with LPG cars getting screwed around.
Anyway, at least you are making headway !
 
#7 ·
Oooo, nearly forgot.

Where are you getting gas from?

I don't need to mention the shite that is being sold as LPG around the place.

Have you noticed different results from different fuels?

When I was running low performance gasoline :p I found best results in both seat-o-pants & dyno results from a place that had a pure propane tanker for BBQ's. ps it was a caltex at the time.
 
#9 ·
Jamie, I'm running a 5/16 single line with an impco model 'L' converter and an impco 425 straight gas carby.

I use LPG from Mobil or BP, but I'm not going to tune the car to use LPG from anywhere special because its going to be for the street... and I can't be picky if i'm running empty! low performance gasoline... :cursethis

Quikcorty, sorry I havn't gotten that back to you. I've been working on the car every day since I borrowed it. Only got the diff in last night! I'll try and get it over to you tomorrow.
 
#10 ·
xacoupe said:
I often wonder if the lack of really powerful LPG cars is not due to the gas but due to the tuner's lack of skills in that area. Looking at all the troubles you have had greg, a competent tuner should know his job well enough to have picked it up ages ago.
You aren't the only one battling incompetence too... there are others with LPG cars getting screwed around.
Anyway, at least you are making headway !
Couldn't agree more Jeff.

I've taken the car to at least 4 different tuners and so far he is the only one that has said "this has nothing to do with the mixer".

Everyone else has just thrown their hands in the air, told me the mixer is too small and tried to sell me another system.

My current tuner actually used the dyno and his knowledge to come to his conclusion right in front of me, basically he said if it was a petrol car leaning out like that, it'd be the fuel pump or a serious problem with the lines. If it was the mixer, he'd expect the a/f to be a lot better and the vac to be much higher (although it is too high at the moment, but thats another story!).

LPG guys, be wary of who you give your cash too.
 
G
#11 ·
Gas tune in Tuggeranong seem good, (for any of the canberra guys) pretty good rates, on my first dyno run for setting the mixture on the mixer he said basically i cant get it right, it needs GAS,
said i needed a bigger gas line as its choking the system,
at this stage it only put out 140rwkw so i said well how much to get all that done, told me the prices and i booked it in,
and he didnt charge me for that failed attempt, so i took it back the week after and got the 5/16 line installed and he set it up and went for 170rwkw,
(also note within that week before i got that done i actually cooked the motor again, and changed the heads from open chamber to closed chamber)

so for under $200 had the problem fixed. (and most importantly the power :D)
 
G
#13 ·
I am told that yes you can, i know a guy over the other side of town that has twin convertors on his supercharged 250 X-Flow, but with a single GRA TB,

but the guy at gas tune told me i can use 2 on the impco if i want or need to...
 
#16 ·
Is 5/16" line big enough?

One other Clevo I had experience with on LPG was stroked, fairly mild and both petrol/lpg.

After many dyno tunes, he ended up running twin 3/8" lines to two convertors with twin line to his custom top mixer.

From memory it made around the 290 horsepower mark on lpg, through a toploader and 3.5 9".

I realize not to have it tuned on peak lpg Greg, I was just asking to see whether you have noticed much difference between fuels.

Keep us informed.
 
#19 ·
hi greg glad u got it running (sort of) cant wait till the supply issue is sorted to see what that cams like can u post s link to the spec so to compare please
cheers m8.
iv hopefully got my impco and parts on there way did u ever hear the whole strange story gregg??? i p,md it to ya but some pms dont seem to get delivered>? so not sure if u ever read it>?
i think my converter is a type e it was off a 460 i wonder if its not quite enough wether i could just add a cheap 4 cyl converter just to give it the little bit extra help rather than fork out ££ on another v8 type
 
#21 ·
STROKEXD said:
I just don't know why people bother with gas. Apart from being cheaper, there's nothing else going for it. If you take the angle that it's all meant to be fun then sure, but I would rather use what works best for me with the least amount of hassles.
I'll tell you why. On the 3 day cruise I just went on I used 350L of LPG. Assuming 10% less fuel usage with petrol (though I find that unlikely) and the average price of $1.15 P/L I would have spent more on fuel than I ended up spending on the entire holiday which included accomodation, meals, etc.

Petrol isn't that much cheaper to setup properly and people have just as many problems trying to get their petrol gear tuned if they choose not to run a holley... because most dyno tuners i've heard of can't seem to tune a thermoquad or a BG carb. Lack of tuning talent isn't going to stop me getting this bloody gas system sorted. If I can get 200rwkw on gas i'd be happy... and I won't be stopping until I've achieved that target.
 
#23 ·
STROKEXD said:
I just don't know why people bother with gas. Apart from being cheaper, there's nothing else going for it. If you take the angle that it's all meant to be fun then sure, but I would rather use what works best for me with the least amount of hassles.
How about not having to breath carcinogens when you refill your car.
 
#24 ·
Mate I used to live near swore by Lpg. He built Hot rods so the lpg made rego much easier. He had very different ideas about it's preformance application and how to tune it. He ran a twin turboed Toyota V8 in a Ford T-bucket on straight gas over ten years ago. He still runs straight gas rods that are very quick. I wish I could tell you what he knows xdc351. Keep at it I'm sure you'll hit 200rwkw with the right setup.
 
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