Author Topic: LACK OF HP  (Read 539 times)

Offline Ä‘uro

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LACK OF HP
« on: July 27, 2017, 07:59:42 am »
morning Gents

Long time hvn't been here.

Hv strange situation with my Arosa..... placed in it G60 charger , port & polished head , all went well but when placed car on dyno and started fine tuning discovered that i can nog get more than 54 HP on wheels ?? when G40 has been placed in it managed to measure 139 Hp on wheels.

Presently boost presure is 1,2 Bar , so charger is ok. Head has been tested, no blowing on side, pipes checked, petrol pump changed ... fm technical side all is ok.

Do somebody know what could be the faliure ? it's strange thing that G60 can give 54 HP...
Is it possible that triger wheel is not in the right phase ? - how I should trim it ?
is it possible that valve springs are not working fine  ?

Tks in advance for your comments
Damjan

Offline GR40

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Re: LACK OF HP
« Reply #1 on: July 27, 2017, 12:14:57 pm »
What cam are you using? You should deffinately check the timing!

Offline ereeiz

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Re: LACK OF HP
« Reply #2 on: July 27, 2017, 01:11:33 pm »
So when it has the G40 charger it runs at 139bhp @wheels, but when you put a G60 charger on there it only makes 54bhp @ wheels?

I'm assuming from your boost pressure you're obviously using the right kind of pulley (I was originally thinking you had a huuuuuuge pulley making the charger turn really slow.)

Is it knocking/pinking?

Have you checked your fuel pressure and flow rate at the fuel rail?

Has ANYTHING else changed since swapping from G40 to G60? Any other signs? Misfiring or anything?

Offline Ä‘uro

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Re: LACK OF HP
« Reply #3 on: July 27, 2017, 01:28:45 pm »
G40 charger it runs at 139bhp @wheels, but when you put a G60 charger on there it only makes 54bhp @ wheels? YES

no im running on 68 mm pulley

FPR - live and kicking with 3,5 Bar and fuel rail is ok.

I changed head. i/o original I hv been placed ported and polish head.

Cam is original . No assimetric Shrick or Cat..

I hv goods fuel pressure. till 3000 rpm car runs ok put when push full truttle everything collaps and engine act like lot of air is missing. air filter is KN 76 mm diameter with intake pipe 80 mm so there is plenty of air.
is it possible that valve springs are not suttible for such pressure ?

Offline Yoof

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Re: LACK OF HP
« Reply #4 on: July 27, 2017, 02:45:08 pm »
Start with the basics.

What have you changed since the car made good power?

You've change the head, so do you still have good compression? Is the cylinder head a PY one? Has everything been timed up properly?

Offline ereeiz

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Re: LACK OF HP
« Reply #5 on: July 27, 2017, 03:18:33 pm »
Checked for air leaks? Perhaps your inlet manifold is loose for example, fine low down, as soon as you build boost the pressure becomes positive and leaks out the join rather than entering the engine.

I would double check everything visually and with a spanner to check its all tight and sealed.

Do you have a stethoscope? You can use a screwdriver, or anything solid that can connect your ear to the head (or wherever you're listening). You can hear leaks and other issues normally.

Offline Ä‘uro

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Re: LACK OF HP
« Reply #6 on: July 27, 2017, 03:49:29 pm »
Start with the basics.

What have you changed since the car made good power?

You've change the head, so do you still have good compression? Is the cylinder head a PY one? Has everything been timed up properly?

Cheers Yoof

Head is PY in good condition and without any cracks. compresion ok.
Only thing what cross my mind is what if the phase are not timed correctly ... for how many degree cam has to be turned ?


Offline GR40

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Re: LACK OF HP
« Reply #7 on: July 28, 2017, 09:51:19 am »
I think you mean how many degrees the ignition has to be set to. If I remember correctly its 6 degrees with the blue sensor unplugged. You should not offset the cam. Time the cam at its original mark, if it's off then that is your problem right there!

Offline Yoof

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Re: LACK OF HP
« Reply #8 on: July 28, 2017, 11:29:21 am »
Start with the basics.

What have you changed since the car made good power?

You've change the head, so do you still have good compression? Is the cylinder head a PY one? Has everything been timed up properly?

Cheers Yoof

Head is PY in good condition and without any cracks. compresion ok.
Only thing what cross my mind is what if the phase are not timed correctly ... for how many degree cam has to be turned ?

Check base camshaft timing (TDC marks and a DTI on the Cyl 1 Piston)

I believe you're on aftermarket management, so once you've confirmed base timing is fine, then check your ECU v actual. If you can fix your ignition timing in your ECU then check with a timing light with dial in advance against the crank pulley. If on digifant the procedure is on here (blue temp removed, elevated idle, and a 5-6'BTDC Ignition)