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Frequent flyer Gold
Posts: 1093
   
Location: An island off southern Tasmania. | Here is the first dyno run on the twin turbo 380GT
Insane power curve, almost vertical.
255KW at the wheels and 700 nM of torque, the tyres were shredding on the dyno.
But you can see where the fuel is running out at about 4000 rpm....
I think that this is the biggest number yet for a 380, I could just leave it at this...but nah, we'll keep going 
Boost was 12 psi....the intercooler was working beautifully, intake temp 31 degrees.
 (380 TT dyno run 1.jpg)
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 380 TT dyno run 1.jpg (336KB - 612 downloads)
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Frequent flyer Bronze
Posts: 45
Location: Perth, WA | Very vertical
What did the A/Rs look like and was the boost stable? |
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Frequent flyer Gold
Posts: 1093
Location: An island off southern Tasmania. | Cashie - 7/2/2013 14:16
Very vertical
What did the A/Rs look like and was the boost stable?
Dunno, that was an off-line screen...the car was off the dyno having the oil catch can and fuel rail mod done. |
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Frequent flyer Gold
Posts: 1093
Location: An island off southern Tasmania. | Here's what happens when you go over about 220kw at the wheels, the fuel pump can't keep up.
they had to tie the car down underneath to get it to stay on the rollers above 220kw atw as well
The flat bit on the dyno chart shows the boost controller maintaining the set level.
notice the boost? 15 psi
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 (dyno shredding tyres.jpg)
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dyno shredding tyres.jpg (354KB - 614 downloads)
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Frequent flyer Gold
Posts: 1093
Location: An island off southern Tasmania. | okay...we came up to a stumbling block.
at around 270kw at the wheels there is a problem with preignition/detonation.
jake the tuner says something in the combustion chamber has a sharp metallic edge that is probably glowing hot and igniting the fuel after about 16-17 psi.
have a look at the pics, the forged engine i bought as a semi complete project from another member is the problem.
those wiseco pistons look all high tech with the valve relief cutouts in the piston crown...but they are responsible for limitting the maximum the engine can deliver.
i had a choice of either of my two forged engines and just picked the wrong one.
Oh well, it will still be the fastest in the world....just not as fast as it can be.
Will probably put the engine with the dish profile in the car in a few months, or put it in the TMR
see the pics and you'll get an idea where the hotspots most likely are.
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 (piston from forged 1.JPG)
 (piston from forged 2 wiseco off the shelf.JPG)
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piston from forged 1.JPG (103KB - 623 downloads)
piston from forged 2 wiseco off the shelf.JPG (79KB - 621 downloads)
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Frequent flyer Bronze
Posts: 34
Location: South Australia | Have you lifted the heads off, you should be able to see the signs of pre-ignition.
These pistons could be machined to remove the extreme sharp edges without compromising the strength. Oil spray on the underside of the pistons the same as Cosworth did on the Sierra Cosworth turbo engine could also help loose heat. |
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Frequent flyer Gold
Posts: 1093
Location: An island off southern Tasmania. | The preignition isn't damaging the pistons, the LINK ecu has a knock sensor microphone so the tuner can here it starting and pulls back the timing accordingly.
I will pull the heads off if i want more boost later.
But i have another forged engine with a simple spoon design as above, so will probably just fit that instead.
My point here is that the Wiseco look all fancy and technical but create other problems that the designet hadn't thought of with...boost!
But as you say I guess we could polish the pistons and that may be the easiest way around it.
Google is full of Wiseco pistons doing this "Wiseco valve relief causing detonation" search that... |
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Frequent flyer Bronze
Posts: 41
| Since you pointed this out I have been doing some research, I'll have a chat to the people that are putting my bottom end together and see what they have to say. Hopefully all that is needed is the sharpe edges ground off. |
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Frequent flyer Gold
Posts: 286
Location: Russia, Perm | John, I wrote to you on an American forum 9G, your problem is not in the pistons. Your pistons (CR8.5:1) withstand 20 psi without prejudice. You do not have enough fuel and very early angle of ignition. |
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Frequent flyer Gold
Posts: 286
Location: Russia, Perm | The last photo Dyno. I don't see the left part of the graph. However, I see the fall of the boost. Turbo works in the blank. This happens if a open wastegate valve. Check the work wastegate valve .
Edited by stayer 25/2/2013 19:39
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Frequent flyer Gold
Posts: 1093
Location: An island off southern Tasmania. | Thanks Stayer...that was the first dyno run...there has been at least 50 more dyno tests since that one.
we installed a return line hose back to the fuel tank on the injector fuel rail to fix that.
but you were on the right track friend. |
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