Jump to content

Found the root of engine problem


Recommended Posts

I just spent 30 minutes typing a hole buch of technical explanations to this stuf and this fuckin thing just toild me to go back and shorten my post  cause it was to long but when I did it was all fuckin gone. BJKHUJK:HBUIVGYVYTOKYBIOOUI:!!!!!!!!!!!!!!!!!!!!!!!!
Link to comment
Share on other sites

  • Replies 75
  • Created
  • Last Reply

Top Posters In This Topic

I just spent 30 minutes typing a hole buch of technical explanations to this stuf and this fuckin thing just toild me to go back and shorten my post  cause it was to long but when I did it was all fuckin gone. BJKHUJK:HBUIVGYVYTOKYBIOOUI:!!!!!!!!!!!!!!!!!!!!!!!!

 

I will do it again later.

Link to comment
Share on other sites

I cant tell from the picture if it is broken or melted.  you can be too lean and have high combustion tempatures that will melt the edge of a piston with no detonation signs.  think of this if you evenly heated the top of the piston with a torch what section will melt first.  the center were there would be the greatest heat disapation or the outer edge of the piston were there is the least bit of heat disapation.  and there is a oil sqiuter helping to keep the center of the piston cool.  Detonation or preignition  or what ever you wish to call it.  it is a explosion of the fuel rather than a controlled burn and it usually happens before it is supposed to happen when the piston is still coming up and it trys to shove it down when the piston has not passed TDC. the ping you hear is  like smacking it with a hammer and trying to go the other direction  this breaks ring lands and the centers out of pistons and bends rods.  lean burns holes in pistons and melts the edges.
Link to comment
Share on other sites

fuel pumps and pressure.

 

Think about this.  Injectors are at 70% duty cycle, your engine is running lean and your pressure falls off.  you do not  have enuf volume to maintain pressure.  You need a bigger pump.

 

injectors are at 100%  duty cycle. you pressure stays constant at whatever it is supposed to be and you are still lean.  you need bigger injectors.  or turn pressure up to flow more fuel.  if you cant maintain higher pressure through out.  you need a bigger pump or fuel lines to feed injectors.

 

if you pressure does not fall off and you are lean I would like to see what your duty cycle is.  most likely you are out of injector not pump.

Link to comment
Share on other sites

boost and manifolds and runners and were it makes power.

 

Why do you use a blow off valve?

because when you let off the throttle all the air that is rushing into the motor hits the closed throttle plate and does a 180 and goes the other way stalling air flow in the intake trac and stalls the turbo.  boost fall offs  and  you have shift lag.  turbo stops you shift step on gas and the turbo has to spool up again.  what  do you think happens when the intake valve closes.

 

if you have a short runner intake  such as that cannon style that reversion of air makes it all the way to the plenum. not only does it disturb the flow of air in the plenum but now when the valve opens the air has to start moving all over again.  hence lag in cylinder fill time before valve closes again.  long runner intakes prevent the reversion of the air when the valve closes from getting to the plenum and  completely stalling the air and there is still a positive pressure pulse at the top of the runner to help get things moving again when the valve opens again.  

 

think about all those small block and big block chevys and fords out there with those tunnel ram intakes  these are 6, 7, 8,000 plus RPM engines and those runners are still about 8-10" long.  now look at your sport bike they have runners that are about 2-3 " long and look were thay start to make power 9, 10, 11, 12,000 RPM

Now look at the new vettes and mustangs that say look 80% of torque at 1500 RPM and there runners are 20" plus.  What makes you think you 6,000 RPM motor wants a 4" runner.  the Aussie intke is the only way to go. or something similair.

Link to comment
Share on other sites

manifolds continued.

 

Look at the dyno report on my car.  notice the brick wall the car hit at 5400 RPM before the plenum change.  the original plenum was 2" thick the new plenum is 3" thick.  now look how the power curve flows and falls off slowly.  also if you have ever seen a dyno report from a short runner intake car you will not that the power curve looks like a Xmas tree rather then a rolling ocean wave  I have a longer power curve that starts earlier in the RPM range because of the runner length and it does not seem to hurt much up top.  but then again what do you want.  25 peak more HP or 75 more ft lbs TQ at a 1,000 RPM sooner.  What gets the car down the track Torque or HP?  torque.  HP is just a measure of work over time.

 

 

 

now for the interesting part.  the power curve that hit the brick wall at 5400 was at 23 PSI  the power curve that was after the plenum change was done at 19.5 PSI  

The same power at a lower boost pressure.  Go figure. Same air flow with less boost pressure makes the same power.  turbo does not need to work as hard because it does not have to make that much pressure to move that much air so there will be a reduction in EX. pressure so more power at less pressure.

 

 

Link to comment
Share on other sites

we finally got our price negotiated with mustang for there 1750 Dyno with the eddie current load cell.  we also have air/ fuel ratio data aquisition as well as 2 pressure channels ( did you say fuel and boost)  How about boost versus exhaust manifold pressure between turbos.   i will be changing  from our stock TD05/ 20G upgrade to a  10cm2 TDO6/20G turbo.  it will be interesting to see all the changes that happen and the effects on power.  we also got   EGT aqusition as well.  
Link to comment
Share on other sites

Bill the piston cracked at the edge there...

 

Like Joel said, why do you think could be causing the drop off at 4K?

 

My dyno runs are right near your torque numbers, but my HP numbers are way lower and the graph looks completely different than yours. Yet my set up is somewhat similar to yours.

Link to comment
Share on other sites

We haven't thought much about the fact that the puff of smoked happened as soon as you let up Mike but tell me if this sounds like a possible explaination for that.  You said the engine ran ok after the damage it just wouldn't idle.  When my head gasket went it ran fine under boost but part throttle cruise and idle were terrible.   My guess is the cylinder was just pressurized at the actual time of the damage so there wasn't much of anything you could feel.  You  were on boost where it ran ok even after the damage.  The puff of smoke must have happened when oil went up through the crack in the piston and past the rings and stuff.  That's why it's good to over run and engine alot during break in right because it draws oil up into the cylinders and speeds breakin?  Some of that oil would have just been allowed up into the combustion chamber.  This may just be so obvious that you guys didn't feel the need to talk about it but a quick confirmation or correction would help me understand.
Link to comment
Share on other sites

I think the puff of smoke came from the fact that there was pressure in the cylinder, and what was contaminating the cylinder was getting immediately burned off. Let off the gas and you fill it up and smoke it out.

 

Joel

Link to comment
Share on other sites

ok these are my Questions and they are important.  if you dont have the ansewers you need to get them so I can help you.

 

 

#1.  What was the Air fuel ratio.  not the one on your 0-1V rich lean or whatever but the AFR from the wide band the dyno uses do you have a print out of your run with it.  if the Dyno does not have  AFR aquisition you need to find another dyno.

 

Do you have a EGT guage reading from the run?

 

Do you have a fuel pressure guage?

 

Tell me everthing done to the car?

 

EX Manifold type?

 

Intake type?

 

injector size?

 

what management system?

 

If haltech send copy of program to my email?

 

have you put a timing light on the motor and compared acxtual with programmed?

 

 

Fill in these Questions and return to me.

 

Bill

Link to comment
Share on other sites

ok these are my Questions and they are important.  if you dont have the ansewers you need to get them so I can help you.

 

 

#1.  What was the Air fuel ratio.  not the one on your 0-1V rich lean or whatever but the AFR from the wide band the dyno uses do you have a print out of your run with it.  if the Dyno does not have  AFR aquisition you need to find another dyno.

-----------------------------------------------------------------------------------------------------

 

18 PSI:                                                          

_________                                            

2250   12.8

2500   12.8  

2250   12.8

2500   13.6

2750   13.1

3000   12.3

3250   11.8

3500   11.1

3750   11.2

4000   12.5

4250   13.0

4500   13.4

4750   13.3

5000   13.4

5250   13

5500   12.9

6000   12.4

 

9 PSI

__________

2000   11.4

2250   13.6

2500   14.0

2750   13.4      

3000   12.5

3250   11.7

3500   11.6

3750   11.9

4000   11.8

4250   11.5

4500   11.5

4750   11.5

5000   11.3

5250   11

5500   10.5

6000   10

-------------------------------------------------------------

Do you have a EGT guage reading from the run?

-------------------------------------------------------------

No, bought a new sender installed the nite before. Gage is faulty. Thought I could get by on wideband O2's.

 

---------------------------------------------

Do you have a fuel pressure guage?

---------------------------------------------

34 psi base 1:1 ~53 psi @ 18psi

 

------------------------------------------

Tell me everthing done to the car?

------------------------------------------

-"super" 20G. TDO6 intake housing 735 cfm garret wheel. TDO5 exhaust housing with TDO6H exhaust wheel. Machined to accept TDO6H wheel

l

- Ported Marnal 2V. Mechanical stock valves. Port matched to gasket.

- Schneider 284F cam. Schneider HD valve springs

- .040 8:1 JE ceramic coated domes/moly coated skirt  TS rings

- 125psi pump. K+N fuel filter stock lines

- BS removed, rods shotpeened stock crank

- Magna MPI SDS ECU 65mm TB

- FUSO IC 2.5" inlets and IC plumbing

- All ARP hardware

- block was decked once head was cleaned up twice.

 

EX Manifold type?

---------------------

Stock with ring removed and lightly cleaned up. Full 3" exhaust with convertor

 

Intake type?

-----------------

Magna 65mm TB

 

injector size?

----------------

Holley 75lb

 

what management system?

----------------------------------

SDS EM3 4E (has ignition control)

 

have you put a timing light on the motor and compared acxtual with programmed?

------------------------------------------

 

Yes, timing is (was) linear with  programmed values from checking at idle and light throttle engagment.

Link to comment
Share on other sites

I am going to assume that on the dyno report the higher #s are at @18 PSI and the other is @ 9PSI.  what did the car do.  sound like when it fell off at 4,000 sis it still sound good while pulling or did it start to sound funny.  the AFR is a little lean above 4,000 should be at least 12.5 (you can run leaner if your EGT's dont get to hot) at full boost but the AFR you have should not cause this type of gragh.

 

Does the boost stay constant or flucuate a # or 2  from the controller.

 

 

What are you timing values at max boost.

 

even though springs may look good or be new  the eraticness of the power curve could indicate valve float.

 

were is the map sensor hose pluged in at on the manifold.

 

Sucks to not be able to data log.  should a bought a haltech.  HEHE just kidding.

Link to comment
Share on other sites

I am going to assume that on the dyno report the higher #s are at @18 PSI and the other is @ 9PSI.  what did the car do.  sound like when it fell off at 4,000 sis it still sound good while pulling or did it start to sound funny.  the AFR is a little lean above 4,000 should be at least 12.5 (you can run leaner if your EGT's dont get to hot) at full boost but the AFR you have should not cause this type of gragh.

----------

 

The higher #'s were on the 15psi run... the 18psi went down in power and the run was never posted.

 

----------

Does the boost stay constant or flucuate a # or 2  from the controller.

----------

 

I have seen the boost move a 1lb up or down via the MAP readings at times. The boost gauge looks to be consitent.

 

---------

What are you timing values at max boost.

----------

 

18 psi was 22 degrees

 

----------

even though springs may look good or be new  the eraticness of the power curve could indicate valve float.

--------------

 

could very well be

 

-------------------

 

where is the map sensor hose pluged in at on the manifold.

--------------------

 

Right under the v. line after the TB...it's t'd in with my mechanical gage

 

http://a5.cpimg.com/image/BD/06/11237565-43a5-028001E0-.jpg

Link to comment
Share on other sites

hmm is their posiblity that the map isnt geting the correct reading? maybe you need to have a deticated line going to the map, or maybe one of the lines that are T'd in are leaking some boost at higher boost levals making the map not get the correct reading.. Just some thots (i did a deticated line to the map from plentum).
Link to comment
Share on other sites

Reset the lifters 2 days before I went in.

 

Somehow I have a feeling the cam needs to be dialed in, questioning the valve springs so I am replacing those too. Along with a new fuel pump, new line and will run my BCFPR inline or get a new FPR.

 

I also question the TDO5 exhaust housing. I'm getting a different turbo that'll smoke my 20G and will definetely outflow it on the exhaust side. Just keeping that a surprise for now...  ;)

 

We'll see just how much this biotch will flow come spring!!

Link to comment
Share on other sites

Looks Nice under there.  The map sensor hose is were it needs to be but it must be dedicated nothing can tee off it.  length of the hose should be as short as possible.  Even though you are teed into to a dead end source the long hose will affect map response.
Link to comment
Share on other sites

  • 3 years later...
 Share


×
×
  • Create New...