Advanced Engine Theory and Design

[NEARING]

Donnie,
Speaking for myself...my lack of response is due to you being light-years ahead of me! Your blurbs are blowing me away!!
Conrad Carter

I second that.

 

[Alky V6]

Donnie,
Speaking for myself...my lack of response is due to you being light-years ahead of me! Your blurbs are blowing me away!!
Conrad Carter

I have a buddy who said something to that affect to me once. It kind of makes you uncomfortable when your friends feel that way about you. I'm afraid it can cause some splitting of friendships sometimes. I just do a lot of reading and observing. I hope that you can learn from me, the same as I have learned through books, experience and others. Isn't that how it should be? Please. If any questions arise or something just clicks and you want to post it, don't hesitate. This is meant to be an exercise for all, including myself. Questions can do wonders to stimulate the thought process.

 

[1dmbth]

Don
maybe you could help me determine a shift point for my my engine.

Stage II on-center
Stage II heads
Stage II intake manifold converted to fuel injection 160 injectors
Cam specs
Valve Adjustment Intake .016 Exhaust .018
Gross Valve Lift Intake .577 Exhaust .590
Duration @ .015 tappet Lift Intake 261 Exhaust 267
Valve Timing Open Close
@ .050 Int: 2- BTDC 46 ABDC
Exh: 49 BBDC 1 ATDC
These Specs are for cam installed
@ 114.0 Intake Center Line

Duration @ .050 Intake Exhaust
224 230
Lobe Lift .3610 .3690
Lobe Seperation 114.0

Gt42-76 turbo
2004r trans
3.42 gear
Need any more information let me know.
Thanks

 

[Alky V6]

The more specs the better.
Bore, stroke, rod length, compression ratio, ring tension (std. or low).
Are you using any coatings?
Standard style rings or gapless?

Are cylinder heads ported? Light port job, max port job.
Valve sizes, flow numbers (if available).

Inside diameter of exhaust primaries, average length of primaries, crossover length and ID, collector length and ID, turbine housing a/r ratio, describe exhaust system, rocker arm ratios, intercooler cfm and efficiency rating, TB diameter, air filter dimensions, intake plumbing ID, torque converter style and stall.

Let's start with that. We'll get into the car specs later.

Stage II heads with a relatively small cam. Should be interesting.

 

[turbot2496]

Thanks Nearing. With the lack of feedback or participation, sometimes I have to wonder if anyone is getting anything out of this

Good gear-turning info, please continue..:smile:

 

[1dmbth]

Bore 4.0"
Stroke 3.625"
Rod Length 6.3"
Compression ratio 9:1
Ring Tension ?
No Coatings
Gapless Rings

Cylinder Heads
Max Ported
valve size Max for stage II head
Flow number-don't have any
Rocker are ratio:?

Exhaust -headers are being made right now by Conley's Performance
Exhaust System-Dual 3" ATR
Intercooler RJC 475
Intake plumbing ID 4"
TB70mm
Torque Converter 5 disc Precision Industries 3800

 

[Hot Air]

Donnie, I, for one, am getting a lot from your discussions. Keep it up and we will catch up with you at some point. You are making me actually think. As a mechanical engineer, I like that.
Conrad Carter

 

[Alky V6]

1dmpth. Do you have any specs on the exhaust? Intake runner length, height, width, taper? I just threw in some specs to fill in the question marks and it looks very nice. What boost are you planning to use? What fuel?
No sense to run 4" intake piping with a 70mm TB. Increase TB size to 90mm or 100mm.
HP is peaking at around 6400rpm. How flat it stays after that rpm is going to depend greatly on the manifolding dimensions. If you can get more specs I'll wait to make a shift point suggestion.

alphaenvirmgt. Thanks for the encouragement.

 

[1dmbth]

Excuse me Don I meant 3'' intake piping.
Header 1 7/8
2 1/2 crossover
boost 15lbs to start with
Fuel Rockett 100 unleaded
The reason for the smallish cam is I plan on driving this car some on the street to car shows etc. and I am keeping the catyalitic converter on it and I am trying to stay away from leaded gas.

I have wanted to participate in the discussions so I thought my own project would be good to use.
Thanks

 

[Alky V6]

Excuse me Don I meant 3'' intake piping.
Header 1 7/8
2 1/2 crossover
boost 15lbs to start with
Fuel Rockett 100 unleaded
The reason for the smallish cam is I plan on driving this car some on the street to car shows etc. and I am keeping the catyalitic converter on it and I am trying to stay away from leaded gas.

I have wanted to participate in the discussions so I thought my own project would be good to use.
Thanks

It's perfect.
Are you running tuned length exhaust or simple stock style headers, just larger?
So far looking like 698 BHP at around 6250 rpm. If this thing reaches peak boost before 5200 rpm keep a look out for knocking. That is one problem with short duration cams with little or no overlap. They can develop a lot of cylinder pressure in the midrange making knock more likely to happen. I would recommend alcohol injection, especially if you plan to increase boost with that same fuel.

 

[Alky V6]

Actually, no overlap or negative overlap can help lower cylinder pressure by diluting the intake charge with exhaust. A kind of tuned in EGR. The above should read, 'short duration cams' only. Disregard, 'with little or no overlap'. When I started adding in some overlap, cylinder pressure at midrange increased which is a sign that the increased scavenging at that rpm would not be a good thing from the stand point of knock.

 

[jjvites]

Don,
One thing here that I would like to hear about that hasn't been mentioned is rod ratio with regard to turbo engines for max power. What is an ideal rod lenght to stroke ratio for best power without getting into detonation that a to long of a rod could cause as the dwell is longer at TDC. Good stuff here.

Thanks,

Marty

Some info I thought I'd put out there. Food for thought.

4 main ways to increase engine power.

Increase cylinder pressure. P
Increase crankshaft stroke length. L
Increase cylinder bore diameter. A
Increase engine rpm. N

Those well read may recognize the above.

Engine rpm limit is directly tied to cylinder head efficiencies and intake valve duration.

Required cam durations and overlap directly tied to cylinder head efficiencies and ?

 

[1dmbth]

Don
I will be using stock style,larger tubes and foward facing turbo.

 

[Alky V6]

Don
I will be using stock style,larger tubes and foward facing turbo.

I'll use an average length of 9" for the primaries. Short or no overlap cams will not be affected much, if at all, by exhaust tuning.

 

[Alky V6]

Don,
One thing here that I would like to hear about that hasn't been mentioned is rod ratio with regard to turbo engines for max power. What is an ideal rod lenght to stroke ratio for best power without getting into detonation that a to long of a rod could cause as the dwell is longer at TDC. Good stuff here.

Thanks,

Marty

A few things come to mind about rod length. A longer rod will:
Slow air speed through the intake port. This could be important if your using a head that is too small for your intended use.
Create less cylinder wall loading caused by the decrease in angularity as the piston travels up and down the cylinder. Important if your using high cylinder pressures. And we all know we like our high cylinder pressures.
As you mentioned, slows piston dwell at TDC and BDC. With more dwell time the charge, after ignition, has more time to build up pressure. Keep in mind that we want maximum pressure at about 14 degrees ATDC. If we've given the mixture more time to build pressure and we want to time maximum pressure to occur at 14 degrees ATDC, then we will need to decrease the spark lead. Retard the ignition timing a bit. This will have the affect of decreasing pumping work loss. An engine loses a certain amount of HP having to compress a mixture while it is also expanding. The perfect situation would be to ignite the mixture at TDC and have max pressure at 14 degrees ATDC. So the closer to TDC we have to move our ignition point the more efficient the engine becomes.

There are some things that will restrict how long we can or should make the rod:
Piston compression height. We run out of room fast with the proper ring package and spacing we need to use with our engines.
Engine block deck height. Not a big problem with the Buick V6. SBCs have it harder in this area.
The limit to how long we really want the beam of the rod to be. This is my opinion. Anyone with thoughts on this are welcome to participate. As you increase HP levels of an engine, the loads transferred to the rod beam will cause it to twist and bend. One engine builder described it to me as watching spaghetti. He witnessed a strobe light setup to a crankcase so that the reciprocating assembly could be watched under load. He said it would scare the hells bells out of you. The valve train engineers do the same thing to look for flex in valvetrain components.
Unfortunately, I cannot give you a limit as far as how long is too long for a rod in our engines. I have only read that you should use as long as possible to keep cylinder wall loading to a minimum. Rod ratio does not seem to affect HP levels of the Buick V6 much. Again, that's what I have read.

 

[jjvites]

I was only thinking in theory and not the limitations of the Buick case. Exactly for the reasons that you mentioned, cylinder side wall loading vs. rod loading. The longer the rod the more it is apt to bend under pressure. With a bigger V8 engines like something in the 400+ cubic inch area does it benefit to be closer to 1.6 rod ratio or 1.9 longer rod to stroke ratio. Just getting opinions.

Marty

 

[Alky V6]

I was only thinking in theory and not the limitations of the Buick case. Exactly for the reasons that you mentioned, cylinder side wall loading vs. rod loading. The longer the rod the more it is apt to bend under pressure. With a bigger V8 engines like something in the 400+ cubic inch area does it benefit to be closer to 1.6 rod ratio or 1.9 longer rod to stroke ratio. Just getting opinions.

Marty

Smokey Yunick recommends going as high as possible on the rod ratio. All the way to 3.0 to one, if possible. His book gives a very good explanation of why the increase in dwell time is advantageous.

'Power Secrets' by Smokey Yunick with Larry Schreib. S-A Design Books. ISBN 0-931472-06-7

To quote out of his book,"But I think the important point can be expressed in simple terms: use the longest damn connecting rod you can fit in the engine!"

 

[jjvites]

I was just reading again an old book of mine by Bill Jenkins and that's what prompted me to ask the question. I also have that copy of Smokey Yunick book. I'm going to look into another old book that I have "Turbochargers" by Hugh Macinnes.

Thanks,
Marty

 

[Alky V6]

I was just reading again an old book of mine by Bill Jenkins and that's what prompted me to ask the question. I also have that copy of Smokey Yunick book. I'm going to look into another old book that I have "Turbochargers" by Hugh Macinnes.

Thanks,
Marty

I once had a copy of Bill Jenkins' book and lost it. Could you post some info on it so I can look around for a copy.

 

[Hot Air]

Does anyone have a copy of the textbook "Turbocharging the Internal Combustion Engine" by N. Watson?
Conrad Carter