Unforgiven Project

They are similar and both reduce the springs own weight at the top. This allows a smaller
retainer and thus is lighter.

A valve spring not only has to control the valve train, but also the spring's own weight. So
reducing the weight of the moving end of the spring helps in this matter.

manton%20valve%20springs-8-700x700.jpg
 
Ok men... I need some help understanding my effective compression.

I am understanding that you do not want to go above 12 when running 91 octane.
For E-85 they are saying no more than 15

Using the calculator... How do I figure the total effective compression with 10 psi boost?


Below is a link to a calculator.

https://uempistons.com/p-28-effective-compression-ratio-calculator.html

Now here is my info on the engine.

My pistons are supposed to be 11.5 : 1
My cam card is below.

index.php


The stroke is 3.75
The rods are 5.7

Below is an effective compression chart.


effective-compression-ratio.jpg
 
http://www.wallaceracing.com/eff-cr.php

I think this wallace calculator is what I was looking for.

Using this calculator above I believe I am seeing :
effective compression at : 9.28
Dynamic compression at : 10.17
Boost compression at : 16.92

So how does this correlate to my engine using E-85? Am I in the safe zone? Or is the boost compression possibly putting me into detonation territory.?
 
if your calculations are correct ??
and boosted compression ratio is shown as 16.92:1,
you're most likely well into potential detonation range.
the use of ethanol (e-85) an ethanol/gas mix, as a fuel ,
and your ignition advance curve will have a very obvious effect on the combustion chamber temps.

keep in mind the effective fuel/air ratio and the ignition advance curve can both be modified,
to reduce any detonation tendency's
and use of an accurate knock sensor,
taking the time to tune,
and verify the fuels true ethanol ratio vs gas ,
content,verifying the ignition advance curve,
and having an oxygen sensor,
vacuum gauge ,
detonation gauge,
coolant temp gauge ,
would be almost mandatory to use under the conditions listed,
remember if your running E-85 your fuel delivery system is going to require
at least a 140%:rolleyes:
GREATER POTENTIAL RATE OF FUEL DELIVERY ON A SUPERCHARGED ENGINE.

if max performance and preventing engine damage was a major concern.
I'D BE FAR MORE CONCERED WITH POTENTIALLY RUNNING A BIT LEAN MOMENTARILY, OR NOT HAVING ENOUGH FUEL VOLUME DELIVERED , AT SOME POINT IN THE POWER/ BAND , IN THE UPPER RPM RANGE THAN IN HAVING THE IGNITION ADVANCE CURVE A DEGREE OR TWO TO FAR ADVANCED AT SOME POINT

this is the most consistently accurate I.R temp gun I've used for testing
42545.jpg

http://www.testequipmentdepot.com/extech/thermometers-and-humidity-meters/infrared-thermometers/high-temperature-infrared-thermometer-58to1832f-50to1-laser-pointer-42545.htm?utm_source=bing&utm_medium=cpc&utm_campaign=NEXT - Bing Shopping - Extech&utm_term=1100200223789&utm_content=All Extech Products
INFRARED TEMP GUN

ethanolvsgas.jpg


https://www.dragzine.com/tech-stori...00-hp-street-engine-big-power-means-big-fuel/

related THREADS AND RELATED CONTENT

http://garage.grumpysperformance.co...your-c4-corvette-runs-badly.15212/#post-87228

http://garage.grumpysperformance.co...y-would-you-swap-to-ethanol.15281/#post-98508

https://www.glowshiftdirect.com/eli...MIqujqhde17wIVBKGGCh3CYQzfEAQYBCABEgI98_D_BwE

http://garage.grumpysperformance.co...ne-running-a-turbo-s-on-e85.10990/#post-73199

http://garage.grumpysperformance.co...g-e85-in-your-old-muscle-car.2141/#post-95594

http://garage.grumpysperformance.com/index.php?threads/build-a-knock-detector.14441/page-2

Related links
http://garage.grumpysperformance.com/index.php?threads/fuel-pressure-regulators.635/


http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.com/index.php?threads/calculate-fuel-injector-size.1200/

http://garage.grumpysperformance.com/index.php?threads/installing-a-fuel-cell.733/


http://garage.grumpysperformance.co...ed-in-a-fuel-system-upgrade.13345/#post-69487

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

https://www.dragzine.com/tech-stori...00-hp-street-engine-big-power-means-big-fuel/

http://garage.grumpysperformance.com/index.php?threads/input-on-electric-fuel-pump-selection.10664/
 
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remember if your running E-85 your fuel delivery system is going to require at least a 140%:rolleyes:
GREATER POTENTIAL RATE OF FUEL DELIVERY ON A SUPERCHARGED ENGINE.

This keeps eating at me....The Holley Sniper has * 100lbs injectors. I am told to keep the fuel regulated at 60psi on the return side.
How do I know I am delivering the extra 40% .... Is it the fuel pumps max delivery that will determine that?
I am using 10-AN lines for supply and 8-AN for return.

I am just trying to dig deeper on what EXACTLY caused my ring lands to disappear, so I do not repeat the same mistake.

Also.. I seen my timing was pulled back to 28* at full throttle.

I am having trouble understanding EFI in general.

Thanks for replying Grumpy.
 
I'D BE FAR MORE CONCERED WITH POTENTIALLY RUNNING A BIT LEAN MOMENTARILY, OR NOT HAVING ENOUGH FUEL VOLUME DELIVERED , AT SOME POINT IN THE POWER/ BAND , IN THE UPPER RPM RANGE

And I think that is EXACTLY what happened.. Earlier I had found the pump to be borderline with fuel delivery.

Remember.... This engine WAS built with matching parts for a target HP level..

The Dyno showed that the combo made WAY more than calculated. This made the fuel pump too small at that point.
 
Thanks Rick.
I read down the link... Great Info! I will do some calculations tomorrow.
I see that it did not take the IVC into account for the calculation though.
I think that would be very important.
 
Grumpy.... Wouldn't the EFFECTIVE compression be the deciding factor for octane rather than the boost compression?

I see the boost compression as something that can be manipulated by the cams IVC events.

I could be wrong ...but
 
yes and no, detonation can be reduced or eliminated , by boosting the fuel octane,
adding cooling capacity to the engine or air temps simply because the issue is keeping out of the detonation range,
use of a larger radiator and fan, adding an oil cooler reduce potential detonation,
detonation is a failure to control the combustion,
detonation is due to several factors but its detectable and correctable,
, and simple changes to the combustion process,
like backing off the ignition timing advance,
in a known rpm range or richening the fuel/air ratio in a known rpm range, is rather easily done
with todays technology your engine control software or your ability to tune, can prevent detonation.
generally you have a oxygen sensor and a knock sensor ,and fuel/air ratio sensors, fuel pressure gauge, and you can change carb jets,
or injector pulse duration, to modify or indicate to you whats going on,
or changes to you what conditions are going on , under a known load, rpm, temperature and rpm range ,etc.
these can be used to point out the temporary, and intermittent lack of proper and controlled combustion.
lets say you make a hard acceleration run, and find that in the 5700-6500 rpm power band your carb or efi , is not providing the combustion control required
if its controlled with a computer processor the program can be changed to match the required changes,
if its you doing the tuning, you make the changes in tuning manually.
slowing the ignition advance in a certain rpm range or richening the fuel/air ration reduces the combustion temps thus preventing the problem.
 
Last edited:
Ok Rick.. You can check my math.

ECR = CR × ((B + A) ÷ A)exponent .74074

CR=11.5
B= 10
A= 14.4 (@ 500')

24.4/14.4 =1.69

1.69 x exponent of .74074 = 1.4747

1.4747 x 11.5 = 16.96

ECR = 16.96

Now if the limit for E85 is 15.1 MAX ECR.
This would show that I am well out of the safe zone.

Lets recalculate with a lower static piston compression of 10 : 1


24.4/14.4 = 1.69

1.69 x exponent of .74074 = 1.4747

1.4747 x 10 = 14.747

ECR = 14.747

According to this formula.... it looks like a 10:1 compression piston would be the correct choice for
running this engine in the correct effective compression zone using E-85.

A 10:1 compression will still give an engine good power down low when NOT under BOOST and not be a (preverbial ) pig until it reaches higher RPM's.

Obviously the cam choice will have alot to do with it also.

I did the math for 10.5 : 1 and came up with an ECR of 15.4843
That would prolly be on the edge.


Now that raises a different question.....How are some guys running 30-50 psi of boost on this juice?

It looks like I'm going to go down another RABBIT HOLE !!! o_O ;)



 
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Thunderbolt.... EXACTLY!!!

Unless their pulling a shit load of timing... maybe down to the teen's.
And using a cam that bleeds some of that pressure off.
 
Last edited:
The engine above uses 26-27 degrees in timing :eek: , i think the combustion chambers/pistons shape are modified to avoid detonation, not as in lowered compression, since it has higher compression than stock.
 
Mine was pulled back to 28*

I keep re reading Grumpy's posts.... I think I did everything correct on my engine.

What I started doing was writing down issues I had with the engine.... right up to failure.

I believe the damage was done on the first test run..

First off...we made 10 great pulls on the dyno... NO SIGN OF DAMAGE.

Then we installed the engine into the truck for the first test hit.

first two passes were great...On the third pass the engine started to lose power ( as in the truck was slowing down).

WE had noticed that the water temp had hit 235*

We let the engine cool down and re started it. What we noticed was the amount of blow by coming out of the valve covers.
The engine seemed to run fine as we drove the truck about a 1/4 mile and onto the trailer.
We pulled the plugs and they looked very clean and the heat mark on the strap was in the correct spot.

WHAT I DID NOT DO was insert the bore scope into the cylinders to inspect the pistons.
If I had done this...I think I would have seen some damage .

I installed TWO 16" fans and build a new and improved shrowd.
Did a couple small test runs and the water temp never went above 195*


Two weeks later we went to an offroad event.

The truck ran good for most of the day. We had a few hiccups here and there but nothing that would indicate imminent
damage. The water temps again never exceeded 195*

Later in the day the wife and I were under full power for about roughly a minute trying to get out of an area
that was swallowing the truck. We had water coming into the cab through the windows and over the sides of the box
which are 76" off the ground.

Once out, we instantly drove into an unseen mud hole that was about 4' deep...

THATS WHEN THE ENGINE QUIT.
It would roll over easy enough,but it just would not fire. And NO...the engine did not ingest water.
Had it towed onto trailer.. And headed home the next day.

Once home...I put the bore scope in the cylinders and took the pics I posted in this thread.
I was then I had recalculated the fuel pump and found that I was running out of flow.

CONCLUSION: GRUMPY IS CORRECT....HEAT KILLED THIS ENGINE

I think the damage was done from the original test run when the temps were too high,
before I fixed the cooling issue.

Second: The fuel pump was just not up to the task...especially when holding at WOT
for a prolonged period of time.

I am sticking with the same compression with the new build.
 
I've been searching for couple of days now and finally found this calculator that considers
the DCR, although they are using an estimated Actual IVC from the IVC angle at .050". If
they use the standard 15° added to the number at .050", then I calculated the number for
the RBRacing calculator to be IVC = 64.5°. This would give a more accurate calc if they
did indeed use the 15° standard.

Your numbers for the Howard camshaft are
IVC Seat-to-Seat: 79.5°
IVC @ .050": 49.5°

I got the 64.5° number by 79.5° - 15° = 64.5°

https://www.rbracing-rsr.com/comprAdvBMW.htm

The two calcs below are identical except for the Static CR of 10.0 and 11.5.

EffectiveBoostCR.jpg
 
Thank you Rick...
I also used the 64.5* IVC. Glad you used the 15 * because that is what I used ,But I added the 15* to the 49.5 instead.

My actual cranking pressure is also right there...we checked it upon first fire up of the engine. I don't have the build book with me that
we created during the build...( we blue printed this engine per say), But I seem to recall a cranking pressure of 170 PSI.
This higher pressure was most likely do to being a brand new build with the rings not being seated yet.

Using the Wallace calculator. I came up with 9.23 dynamic.... and dynamic boost was 15.34
I came up with piston travel at 21.62%..which amounts to 2.94 effective stroke.

I think this proves that this engine was well thought out and built for a specific fuel and target HP!!!!!!

WE (as in YOU and I RICK) did a fantastic job planning and designing this engine!
Also Coty and I... I feel did a great job on the actual build.

This reaffirms my thinking that it was an over heat and too small of a pump that caused the issues.
My only other concern is tat the pistons were 2618 forgings, and I only had my piston to wall clearance at .0045

I have not yet pulled the pistons out of the bore yet...but from what I can see on the cylinders, there is
no sign of seizure.

I am going to rebuild with the same pistons. I can back the boost down a couple pounds for safety if need be.o_O :)
 
Ok Rick...Grumpy had posted a cam card back on page 69 of this thread. post #1369

I'm ready for a new simulation..


Can you plug that into your computer for me.. everything is the same except for:

1 3/4 long tube headers.. ( 2 1/2" exhaust with straight though magnaflow mufflers) you can work out a collector length.
I may also go with a 3" exhaust..I think with a blower, it might benifit.
11:1 compression
4-6 psi boost.
1.5 rockers

I looked at the Crane catalog and would like to see this cam compared to the one TWO sizes smaller also. The part # is HR-222/345-2S-12.90 IG

No hurry Rick... Just when ever you get the time.
 
I typically work on these things in the afternoon, like starting around 3 pm. Besides Dynomation, I
also have PipeMax for designing headers. Now PM requires a lot of measurements, like port length (PL)
at the centerline and port volume. To measure PL you will need to use some 1/8" pin-stripping tape
and lay it along the short side and long side. Then pulling out and lay them down in a straight line to
measure, then take the average. Also need a actual Dyno output for best accuracy, but our simulation
will work. Might have something tomorrow maybe.

Be sure to page down, there is lots of info.
http://maxracesoftware.com/PipeMaxPro400.htm

Just depends on how far you want to take the theoretical.
 
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