Geometry Talk

W

Windsor377

Guest
Ever wonder about bottom end engine geometry?

How about the relationships between the connecting rod length, the crankshaft stroke and the cylinder bore?

It's fairly common knowledge that engine displacement =

((bore/2)^2)*Pi*stroke*nbr of cylinders

But what does that really mean? How does that influence the torque and power curves? Does the connecting rod have any influence? If so, what?

Is it all secret stuff that you accidently get right sometimes and miss the rest of the time?

....
 
Yes and Yes

Generaly, oversquare engines produce more horsepower at higher revs compared to undersquare engines that produce more torque at lower revs. Connecting rods play a big role and it something that I think I know about. Let me explain...

The ratio between the connecting rod length and the stroke length of a motor greatly affects the way it performs, and how long it lasts. This ratio can be calculated as follows:

Ratio n = Rod Length ÷ Stroke

The rod’s length is measured usally from the center of the piston-pin opening to the center of the big-end bore, not overall. There is a small range of ratios for most conventional piston engines: the rod is between roughly 1.4 and 2.2 times the stroke length. It’s not possible for the rod to be the same length as the stroke, and rods much longer than twice the stroke make the motor very tall,not practical for most purposes, but there is some used for racing.
The rod angle must not encourage excessive friction at the cylinder wall and piston skirt. A greater angle (smaller value of n) will occur by installing a shorter rod or by increasing the stroke. A reduced angle (larger value of n) will occur with a longer rod or a shorter stroke.


If the rod length is decreased, or the stroke is increased, the n ratio value becomes smaller. This has several effects. The most obvious is the mechanical effect. Motors with low values of n ( short rods or long strokes) typically exhibit the following characteristics when compared to high n motors. Overall shorter (more clearance for headers, pan, air filter), thus a lower block weight, but because of this higher vibration should result, and higher operating temps. It also affects the way it breaths. Intake vacuum will rise sooner, therefore allowing bigger carburetors or intake port runners and plenum volumes to be used without loss of response.

Tried to sound as professional as I can :) out of time for now, more to come on the pros and cons of long and short rods....
 
This is what I have in my notebook on the pros and cons of long and short rods.

Effects of Long Rods

Pros:
Provides longer piston dwell time at and near TDC, which maintains a longer state of compression by keeping the chamber volume small. This results in better combustion, higher cylinder pressure after the first few degrees of rotation past TDC, and higher temperatures within the combustion chamber. This type of rod should produce very good mid to upper RPM torque.
The longer rod will reduce friction within the engine due to the reduced angle which will place less stress on the surface of the piston during combustion. These rods work well with numerically high gear ratios and lighter vehicles.
For the same total deck height, a longer rod will use a shorter, lighter piston, and generally have a safer maximum RPM.


Cons:
They do not promote good cylinder volumetric efficiency at low to moderate engine speeds due to reduced air flow velocity. After the first few degrees beyond TDC piston speed will increase in proportion to crank rotation, but will be biased by the connecting rod length. The piston will descend at a reduced rate and gain its maximum speed at a later point in the crankshaft's rotation.
Longer rods have greater interference with the cylinder bottom & water jacket area, pan rails, pan, and camshaft - some combinations of stroke length & rod choice are not practical.
Camshaft selection must be carefully considered. Long duration cams will reduce the cylinder pressure dramatically during the closing period of the intake cycle.



Effects of Short Rods

Pros:
Provides very good intake and exhaust velocities at low to moderate engine speeds causing the engine to produce good low end torque, mostly due to the higher vacuum at the beginning of the intake cycle. The faster piston movement away from TDC of the intake stroke provides more displacement under the valve at every point of crank rotation, increasing vacuum. High intake velocities also create a more uniform so to speak air/fuel mixture within the combustion chamber. This will produce greater power output due to this effect.
The increase in piston speed away from TDC on the power stroke causes the chamber volume to increase more rapidly than in a long-rod motor - this delays the point of maximum cylinder pressure for best effect with supercharger or turbo boost and/or nitrous oxide.
Cam timing (especially intake valve closing) can be more radical than in a long-rod motor.


Cons:
Causes an increase in piston speed away from TDC which, at very high RPM, will out-run the flame front, causing a decrease in total cylinder pressure at the end of the combustion cycle.
Due to the reduced dwell time of the piston at TDC the piston will descend at a faster rate with a reduction in cylinder pressure and temperature as compared to a long-rod motor. This will reduce total combustion.



What have you found to work the best with your setup?
 
Excellent Nate!...and room for plenty of discusion!

At the rpm ranges and combiations I run, my rod stroke ratios are pre determined for me and usually wind up in the mid 1.60s to 1.70s :1

Like this:

R/S = (Deck height) - (Shortest Piston CD I can get away with) - (Stroke/2).

Are you familiar with this or similar algorithm?

Instaneous Piston Velocity = IP

Mean Piston Velocity = MV

MV=2*stroke/12*rpm....figure stroke in inches. Dividing by 12 gives you feet and the results will be in ft/min.

Crank Throw = Stroke/2=CT

Crank Angle = CA

Connecting Rod Length=CL

IP=MV*Pi/2*sin(CA)*[1+(cos(CA)/(sqrt(((CL/CT)^2-sin(CA)^2))))]


...gotta go for now, basketball game, then gymnastics...
 
...forgot something:

R/S = [(Deck height) - (Shortest Piston CD I can get away with) - (Stroke/2)]/Stroke.
 
Originally posted by Windsor377@Feb 22 2003, 10:42 AM


Are you familiar with this or similar algorithm?
Click to expand...
I have seen it before, haven't done anything with it though. This is a pretty simple question but, How do you use it? and What does it tell you?
 
Originally posted by Windsor377@Feb 22 2003, 10:42 AM
At the rpm ranges and combiations I run, my rod stroke ratios are pre determined for me and usually wind up in the mid 1.60s to 1.70s :1
Click to expand...
Being around that ratio, this is what I assume but it may not match up for racing engines...

that you are using a large intake port volume(vs. the engine size), most likely a single plane manifold, therefore a large carb.
 
Originally posted by NateDogg+Feb 23 2003, 08:30 PM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (NateDogg @ Feb 23 2003, 08:30 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--Windsor377@Feb 22 2003, 10:42 AM


Are you familiar with this or similar algorithm?
Click to expand...
I have seen it before, haven't done anything with it though. This is a pretty simple question but, How do you use it? and What does it tell you? [/b][/quote]
It allows to to map instantaneous piston velocity for any given rod/stroke combiantion at any rpm. Once you get used to it you can then begin mapping vs cam profile, valve movement, air flow. If you stick with it, you can begin creating other algorithms which read these results to begin predicting hp.

You can also predict loads and if you remove the velocity components, you can use it to predict piston drop to help with baselining initial setup of new combinations, before purchasing parts.

...but I think it's biggest help for me was just helping me better conceptualize how and what changes as something else changes.

I have a simplified version that I put into an excel spreadsheet. There are 3 tabs. One give readings at every 0.1 degree, one at every degree and one every 10 degrees.

If you have excel, I can send you a copy. I made it in excel 2000, but I think 97 should work too.
 
that can be extremly helpful, especially a novice like me :) My cousin or the owner has never mentioned it before. Yeah I have excel, go ahead and send it :)

So you pretty much can determine the effects of every thing that changes, thats awsome.
 
Originally posted by NateDogg+Feb 23 2003, 08:46 PM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (NateDogg @ Feb 23 2003, 08:46 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--Windsor377@Feb 22 2003, 10:42 AM
At the rpm ranges and combiations I run, my rod stroke ratios are pre determined for me and usually wind up in the mid 1.60s to 1.70s :1
Click to expand...
Being around that ratio, this is what I assume but it may not match up for racing engines...

that you are using a large intake port volume(vs. the engine size), most likely a single plane manifold, therefore a large carb. [/b][/quote]
Pretty good and here's where it gets real interesting.

What would you think of the following combination:

Very small port cross section (2.010 x 1.540 intake opening),
Smallish valve 2.150
Fairly large SB (4.155 x 3.900),
Kinda short rod 6.200
CR 15:1

Intake Flow Curve @ 28" (exhaust is high 70s%):
.100-71 CFM
.200-153
.300-228
.400-295
.500-334
.600-357
.700-373
.800-383

Can you save this? Or is it a basket case? If you could predict rpm of max hp and torque, what would they be?...want to try for the max hp and torque values too?

P.S. I would say everything you stated in your original responses is 100% correct if the only thing changed was R/S ratio. I would also say that the concept of long vs short is relative.
 
Originally posted by NateDogg@Feb 24 2003, 07:32 PM
that can be extremly helpful, especially a novice like me :) My cousin or the owner has never mentioned it before. Yeah I have excel, go ahead and send it :)

So you pretty much can determine the effects of every thing that changes, thats awsome.
Click to expand...
I'll send a copy...gotta switch computers...this spreadsheet only handles rod/stroke/rpm changes...once you get used to it, then you can begin to build in the other stuff....always save an origial before making changes to a working copy.

I've got other utilities that tie all the info together, but they were written 20 years ago in GW basic...I cant send that to you, but I can help you figure out how to add the rest (or a lot) to your copy of the spread sheet.

A lot of it boils down to incorporating empirical data to help with constants.
 
...hmmm I can't attach a file to a private message and when I choose email it the system responds with some message to the effect that it's not set up???

Does this board have anyother way to send a file?...or can you set up a temporary Msn Hotmail or Yahoo account that you don't mind posting on the board?
 
Originally posted by Windsor377@Feb 24 2003, 06:56 PM

Can you save this? Or is it a basket case? If you could predict rpm of max hp and torque, what would they be?...want to try for the max hp and torque values too?
Click to expand...
Haven't had much time to look at it yet, but just with the basic information, we are lookin at about a 423cid engine. So I just assume its a big block? that is starting to get some serious flow. I would have to say that engine is making power in the high 7's low 8's, with mabey 820hp @ 7850 and 675ft/lb @ 4900 or so. I know this is probally way off, haha, but thats what I am sayin for now :)
 
Originally posted by NateDogg+Feb 26 2003, 10:27 AM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (NateDogg @ Feb 26 2003, 10:27 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--Windsor377@Feb 24 2003, 06:56 PM

Can you save this?&nbsp; Or is it a basket case?&nbsp; If you could predict rpm of max hp and torque, what would they be?...want to try for the max hp and torque values too?
Click to expand...
Haven't had much time to look at it yet, but just with the basic information, we are lookin at about a 423cid engine. So I just assume its a big block? that is starting to get some serious flow. I would have to say that engine is making power in the high 7's low 8's, with mabey 820hp @ 7850 and 675ft/lb @ 4900 or so. I know this is probally way off, haha, but thats what I am sayin for now :) [/b][/quote]
Not too far off. But it's a fairly big small block. I'm curious about the torque numbers. That's a pretty big torque/cid value.

Here's where empirical data can help out (this is for N/A).

Torque numbers near or over 1.6lbs-ft/cid are usually suspect in a N/A engine. An engine tuned for max hp is usually in the low to mid 1.40s.

Also, a drag race engine will typically have about 1500 rpm between max torque rpm and max hp rpm.

Now with all this being said, you might predict max torque of 613 using a 1.45lbs-ft/cid. Now mix that with your pretty accurate hp @ rpm numbers and you would have:

820 hp @ 7850rpm
613lbs-ft torque @ 6350 rpm

Not a bad prediction, but a little more empiriacl data over the years and you would be able to get it closer.

In actuality the numbers were:

850 hp @ 8100 rpm
615lbs-ft torque @ 6700 rpm.

Now, can you think of reasons why it is important to have accurate hp predictions prior to building your engine?
 
Originally posted by Windsor377@Feb 26 2003, 05:28 PM

Not too far off. But it's a fairly big small block. I'm curious about the torque numbers. That's a pretty big torque/cid value.

Here's where empirical data can help out (this is for N/A).

Torque numbers near or over 1.6lbs-ft/cid are usually suspect in a N/A engine. An engine tuned for max hp is usually in the low to mid 1.40s.

Also, a drag race engine will typically have about 1500 rpm between max torque rpm and max hp rpm.

Now with all this being said, you might predict max torque of 613 using a 1.45lbs-ft/cid. Now mix that with your pretty accurate hp @ rpm numbers and you would have:

820 hp @ 7850rpm
613lbs-ft torque @ 6350 rpm

Not a bad prediction, but a little more empiriacl data over the years and you would be able to get it closer.

In actuality the numbers were:

850 hp @ 8100 rpm
615lbs-ft torque @ 6700 rpm.

Now, can you think of reasons why it is important to have accurate hp predictions prior to building your engine?
Click to expand...
I am just used to 400cid being the sutoff between small and big blocks for factory engines. Should have known better.

As for the trouque, I have a diesel background, drive a deisel truck, my dad was an engineer with a heavy equipment manufacture that delt with big cummins and detroit diesels. My truck torque curve is at 1800, so the little guy in my head seems to think like that, haha.

Those ratios are good to know for a young guy like me :) Have learned most things take experience.

Not only important to know how much horsepower, but where at. Having hp numbers before its even built would be crutial for low budget teams like most all of us. Horsepower goes up a little every year and you have to keep up. Also excellent for comparing engine to engine, if one is thinking about a new setup, that would tell your potential of the new vs the old setup.
 
Good again, but here's something else to consider.

I'm sure you are aware that the exhaust and intake is tuned to the characteristics of the engines power curve. A mistake in header and intake design will cost the engine torque, hp and rpm and it will never produce it's potential. Get the exhaust and intake right and you will let your engine produce to it's full potential.
 
Originally posted by Windsor377@Feb 27 2003, 06:40 PM
Good again, but here's something else to consider.

I'm sure you are aware that the exhaust and intake is tuned to the characteristics of the engines power curve. A mistake in header and intake design will cost the engine torque, hp and rpm and it will never produce it's potential. Get the exhaust and intake right and you will let your engine produce to it's full potential.
Click to expand...

Most of my knowings of exhaust are from the stock world of engines.
Headers with 1-1/2-inch primary tubes will carry an engine well into the 300 horsepower range, while 1-5/8-inch headers can support up to and beyond 400 horsepower in some cases. This I think depends a great deal on displacement and engine speed. I have seen in magazines 1-3/4 headers support up to around 550 horsepower without affecting power on a single four barrel 350 Chevy running at 7500 rpm, while a 480 horsepower, twin carburetor 302 running at 8000 rpm gained 13 horsepower by switching to 1-7/8-inch primaries. I think it is usually better to err on the small for a street engine so that torque remains strong. Pipes that are too large are generally thought to hurt the bottom end more than small pipes hurt the top end, but in many cases the dyno has shown that too large a header does not hurt as bad as you might expect, especially on a larger engine that makes torque easily.

So drag racing = big?

Intakes (Indivudual Runners) make the best power the higher you go. Whats the cut off? Each inch higher lets say, how much horse power is going to gain, there has got to be some curve for that, angles change higher they get, don't know if that has anything to do with it. Also those inch spacers between the carb and intake, how does that affect hp? I have heard +10.


By the way, what are the keys for determining for peak hp @ rpms? mabey I was missing something, why I was off a little.
 
Originally posted by NateDogg@Feb 28 2003, 12:17 AM
So drag racing = big?....

....By the way, what are the keys for determining for peak hp @ rpms? mabey I was missing something, why I was off a little.
Click to expand...
Well, not exactly. The engines power corve makes all the determinations. I need to run a few combinations as examples....stay tuned

....keys for determining hp @ rpm...there are a few products and algorithms available, but those things are based on a pre-determined way to build the engines. My algorithms do to...it's based on you own empirical data and constants to help combine your way of doing things with what the engine makes available to you.

I've got another spread sheet that maps cylinder head flow against measurments of your cam and gives me some REAL close estimates of 600 rpm/sec pulls...mind you, it is based on my way of doing things...and as my way changes, I need to modify the constant accordingly.

Let me "genericize" a copy and send to you...stay tuned...I may not get to it today...
 
Originally posted by NateDogg@Feb 28 2003, 12:17 AM
So drag racing = big?
Click to expand...
Ok, here's some more to think about. Remember it's the engine thagt determines header dimensions. Not the form of racing. Example:

There are two engines. One a 355 cid small block another a 464 big block. They both make around 1050HP. Here are the specifics.

Small Block

4.155 x 3.27
Rod = 6.300
CR = 17:1
Max HP occurs at 10500 rpm

Big Block

4.440 x 3.75
Rod = 6.800
CR = 16:1
Max HP occurs at 8200 RPM

Take a guess at header dimensions for each. How about minimum carb as well?
 
1050hp? out of a small block :bounce:

Primary tube x collector
small block: 1 7/8 x 3
big block: 2 1/8 x 3 1/2

Carb I would imagine would have to be at least to be in the 800cfm range
 
I don't know If my answer can be that standard. Seems like you would have to know flow rates for a small at 10k and a big at 8. hmmmmmmm...
 
Originally posted by NateDogg@Mar 5 2003, 10:48 PM
1050hp? out of a small block&nbsp; :bounce:

Primary tube x collector
small block: 1 7/8 x 3
big block:&nbsp; &nbsp; 2 1/8 x 3 1/2

Carb I would imagine would have to be at least to be in the 800cfm range
Click to expand...
Talk to Bob Panella, Greg Stanfield and Randy McDaniels Dad!!!!...can't rememeber his name right now.

Actually flow numbers are not consequential! Believe it or not. Any guess on lengths as well?
 
Originally posted by Windsor377+Mar 6 2003, 07:28 PM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Windsor377 @ Mar 6 2003, 07:28 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--NateDogg@Mar 5 2003, 10:48 PM
1050hp? out of a small block  :bounce:

Primary tube x collector
small block: 1 7/8 x 3
big block:    2 1/8 x 3 1/2

Carb I would imagine would have to be at least to be in the 800cfm range
Click to expand...
Talk to Bob Panella, Greg Stanfield and Randy McDaniels Dad!!!!...can't rememeber his name right now.

Actually flow numbers are not consequential! Believe it or not. Any guess on lengths as well? [/b][/quote]
First: Appologies to Randy Daniels....McDaniels...hmmm, I always make that mistake. I knew a fella named Randall McDaniel.....

Anyhow try this:

SB Header Specs:

2.375 X 25.5 w/ 4.432 X 10" Collector.

Step header:

2.250 X 10.8
2.375 x 6.1
2.500 x 5.6

Same collector

BB Header Specs:

2.344 X 30.7 w 4.376 X 13.4 Collector

Step Header:

2.200 X 14.7
2.344 X 8.3
2.469 X 7.7

Same collector.

The BB wanted a 1250 min carb, the SB 1150 min.

Interesting?
 
Yes. The only thing more on the small block is the compression ratio. So you might have to explain why the SB is bigger and shorter than the BB. :)
 
Originally posted by NateDogg@Mar 10 2003, 09:56 PM
Yes. The only thing more on the small block is the compression ratio. So you might have to explain why the SB is bigger and shorter than the BB. :)
Click to expand...
Believe it or not RPM. For 2 reasons. The faster rpm is trying to expell the exhaust gasses real fast...so there is an influence to increase pipe diameter. Also, typical wisdom (pending an argument with Gebbler) says you want to take advantage of 3 sonic pulses through the exhaust system and have the third coincide with the beginning intake cycle. Faster turning engines need shorter pipes to fit those cycles in....now that being said, I've seen Pro Stock headers that sure look like they are trying for 4 sonic pulses.

Now if the BB made peak power at 8400 rpm instead of 8200, I would run the same or even a little (REAL LITTLE) larger in diameter than the SB....I had to "fabricate" the situation, but this demonstrates how being able to predict HP and torque numbers @ rpm can be so important?

...by the way, I owe you another spreadsheet....been real busy, but I'll genercize one for you...at some point.
 
ok, RPMs make perfect sense. So roughly BB and SB can be the same size if the BB is running about 2000rpms less. OK thats for pretty big engines, while this conserns RPM, then F1 engines, latest engines from BMW and Honda are pushing 19000, they got little tiny cylinders, but spin real fast. Whats the deal with that? Is there any relationship to the cid on the cylinder?

but the sonic pulses, what would be the advanadge of a pro stock going for 4 pulses?

By the way is that small block yours?
 
Originally posted by NateDogg@Mar 14 2003, 07:17 PM
ok, RPMs make perfect sense. So roughly BB and SB can be the same size if the BB is running about 2000rpms less. OK thats for pretty big engines, while this conserns RPM, then F1 engines, latest engines from BMW and Honda are pushing 19000, they got little tiny cylinders, but spin real fast. Whats the deal with that? Is there any relationship to the cid on the cylinder?

but the sonic pulses, what would be the advanadge of a pro stock going for 4 pulses?

By the way is that small block yours?
Click to expand...
Good questions Nate. Cylinder volume does play a role, together with rpm as the main contributors. CR, makes a difference, rod/stroke a bit as well, but mostly affect length.

So, little bitty cylinders with a lot of rpm and torque in the mid 1.40s lbs-ft/cid will rely on the same basic principles...give me some more time and I'll try to map a set of headers for a BMW. What would you say, max hp of 875hp @ 18,000rpm?

I messed up on the 4 pulses deal, I should have said 2. I've seen some ultra high rpm headers that just look WAAAAYYYY long. It has to be for 2 pulses. Why??? I don't know and haven'ty had the time or $ to play with it....it's just something I've seen. There might be some theoretical advantage that I don't see right now, if so, it might fall into the 55 degree vavle seat category...that is, looks good on paper, but not on the dyno.
 
Originally posted by Windsor377@Mar 18 2003, 05:25 PM

What would you say, max hp of 875hp @ 18,000rpm?
Click to expand...
yeah, roughly. Its hard to get real numbers from F1 but, BMW claims 920hp and they are pusing 19000rpms.


I messed up on the 4 pulses deal, I should have said 2.&nbsp; I've seen some ultra high rpm headers that just look WAAAAYYYY long.&nbsp; It has to be for 2 pulses.&nbsp; Why???&nbsp; I don't know and haven'ty had the time or $ to play with it....it's just something I've seen.&nbsp; There might be some theoretical advantage that I don't see right now, if so, it might fall into the 55 degree vavle seat category...that is, looks good on paper, but not on the dyno.
Click to expand...

ok, I will check that out. Might just ask a Pro Stock guy at the next nationals I am at :)
 
Originally posted by NateDogg+Mar 18 2003, 08:30 PM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (NateDogg @ Mar 18 2003, 08:30 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin--Windsor377@Mar 18 2003, 05:25 PM

What would you say, max hp of 875hp @ 18,000rpm?
Click to expand...
yeah, roughly. Its hard to get real numbers from F1 but, BMW claims 920hp and they are pusing 19000rpms.


I messed up on the 4 pulses deal, I should have said 2.  I've seen some ultra high rpm headers that just look WAAAAYYYY long.  It has to be for 2 pulses.  Why???  I don't know and haven'ty had the time or $ to play with it....it's just something I've seen.  There might be some theoretical advantage that I don't see right now, if so, it might fall into the 55 degree vavle seat category...that is, looks good on paper, but not on the dyno.
Click to expand...

ok, I will check that out. Might just ask a Pro Stock guy at the next nationals I am at :) [/b][/quote]
OK. I'm going to go with my numbers and assume that 920 hp claim is a steady state rating and not from an acceleration pull. I'll also assume 19000rpm is 1000rpm past max power...That's a 10 cylinder right?

That would ghive me primary pipes measuring 2.043" X 13.3" I didn't calculate the collectors, but I bet they would be close to 4" X 5.5"...or 11", but that would weaken the effect.

...and hey!!! Get some info on Panella's Mustang...see if he is willing to say whose technology he is using.

Thanks in advance.
 
Nate, I just sent taht generic flow sheet/power estimator. This one is hard coded for certain assumptions. It will hit max HP rpm within 50. I talked about it in the email...I used the old email you posted earlier.
 
allright, got it. Thats pretty cool to play with, thanks a lot.

I am looking up what the actual header sizes are for an f1 engine.

I will look Panella up, might have to take my chevy hat off though, haha.
 
Originally posted by NateDogg@Mar 25 2003, 07:49 PM
allright, got it. Thats pretty cool to play with, thanks a lot.

I am looking up what the actual header sizes are for an f1 engine.

I will look Panella up, might have to take my chevy hat off though, haha.
Click to expand...
Don't forget, he had one of the fastest Chevy PSTs out there!
 
Hey Nate, this is still a cool thread. We need to start adding to it!
 
yeah its cool, sometimes I use it for an reference, heh. Whats next on the list? Cams have geometry, heh heh.
 
You must log in or register to reply here.
Back
Top Bottom