Engine Parts Selection Tech Article

[cage]

Boof, maybe put which rod is which with the I and H beam, you could put it in the picture description e.g. I beam top, H beam below. Hope I am not being too picky but knowing you like i do you will like this.

[cage]

Question please Dr Boof, the VE verses MPS is hard to get your head around but I will try.

Using your calculators I have a VE of 90% and my MPS is 3683ft/min, so if I am getting this, that will mean that I am well inside the VE limit in regards to my piston speed. Again if that is correct, what does that actually mean in practical terms? Does it mean that I have more performance capabilities in my engine in regards to increasing the VE? Therefore technically look for other part options to maximise this such as possibly EFI. Or boost it, but then the compression at 10.5:1 is probably too high.

Or does it simply mean that I am in a good zone for my engine and although it has more VE capacity capabilities, going to the limit based on the MPS brings in unrealibility due to greater stress?

However in a race care example does that mean they would be trying to max out the MPS to the point where the VE limits are reached? Therefore this is why there RPM is so much higher than a street car?

Or have I completely got this wrong?

[ozbilt]

Or have I completely got this wrong?

One thing for sure, you have lost me ........

[cage]

Yeah I think I lost myself writing it.

[boofhead]

Boof, maybe put which rod is which with the I and H beam, you could put it in the picture description e.g. I beam top, H beam below. Hope I am not being too picky but knowing you like i do you will like this.

Not picky - good feedback is great. I have made a small change to the description
to make it clear to the top picture is the I beam hence bottom is the H beam rod.

[boofhead]

Question please Dr Boof, the VE verses MPS is hard to get your head around but I will try.

Using your calculators I have a VE of 90% and my MPS is 3683ft/min, so if I am getting this, that will mean that I am well inside the VE limit in regards to my piston speed. Again if that is correct, what does that actually mean in practical terms? Does it mean that I have more performance capabilities in my engine in regards to increasing the VE? Therefore technically look for other part options to maximise this such as possibly EFI. Or boost it, but then the compression at 10.5:1 is probably too high.

Or does it simply mean that I am in a good zone for my engine and although it has more VE capacity capabilities, going to the limit based on the MPS brings in unrealibility due to greater stress?

However in a race care example does that mean they would be trying to max out the MPS to the point where the VE limits are reached? Therefore this is why there RPM is so much higher than a street car?

Or have I completely got this wrong?

Your engine is actually in a very good spot. I did not expect it to produce the power it did. I was expecting 30hp less so I was very pleased. The reason I believe is the 500 extra RPM you were able to pull on the top end due to the 8019 spring set that were installed into the heads.

The VE guide based on Piston Speed is to present an upper limit on possible HP. 90% plus is excellent for a street engine to get higher your looking at porting, port matching, optimising intake and intake lengths, exhaust sizing etc so really the extra becomes a lot more work and cost - which for a street engine is not worth the effort - you just go larger or forced induction.

[boofhead]

Last few points
1) 10.5:1 is a little high for boost though it can be done and is very reasonable if you start
using boost with Alcohol based fuel mixes such as E85. There are people who go light
boost (5 psi or so) and have no issues on 98 (though tune is very important the closer
to the sun you get).

2) Minor increases in RPM make a huge difference in performance as you go higher in the range. 5000 to 5500 not such a big deal but 6000 to 6500 is and going to 7000 larger again then large step again to 7500 etc.. You can see it on potential HP calculations and VE potential. More RPM equals more stress means more money being spend on insurance parts as well as performance parts so costs rise very quickly.

3) Yes a race engine is trying to get absolute highest VE possible - a small difference can bring the win or come last as everyone is looking for that last 1% to get the edge. Look at an F1 engine - cost 30 million while yours was (from memory ) $800.

[boofhead]

Hi Boof, I am a bit behind but just finished off the first part. I am happy to be shot down but under the brakes section there is no mention of the master cylinder (making sure the reservoirs, in particular the rear, are large enough for the new brakes - big point when engineering) or the possible need for a brake proportioning valve to get the brake bias ratios right between the front and rear. Might be worth adding just so people are aware to research that as well.

I looked at the brake section and I have found one sentence

Quote

"The master cylinder in most cases will need to be upgraded as well as is the possibility for the requirement of a proportional valve."

End Quote

Do I need to expand on this? I am happy to as it there is no explanation of why.

[cage]

Great thanks Boof, at least I was on the right track.

Sorry I must have missed that sentence re the master cylinder, my bad. That gives enough info for further research.

[boofhead]

I have posted the remaining sections of the article so it is complete other than refinements and an extra FAQ questions that need to be added. I hope the readers have learned something and this is a helpful resource for us all. Please link to the article where ever you feel it might help someone (assuming you think it is worthy).

I would like to complete part 2 which is actual building the engine from the parts. See how I go. This one has taken a huge amount of my time so I am a little gun shy at the moment. It will be a far easier article as it is straight forward step by step instructions.

I do look forward to any feedback.

[nassi]

Mate, you are outstanding. I still have not found the time to completely read it so how the hell did you find the time to write it?
Many thanks.

[hybrid]

Nice one boof. I had another quick read through over the course of the morning.

[Pinto-Pete]

Good to see work didn't get in the way of your leisure time there gee off.......

[nassi]

Good to see work didn't get in the way of your leisure time there gee off.......

A bit rich coming from you Pee off.

[Pinto-Pete]

Good to see work didn't get in the way of your leisure time there gee off.......

A bit rich coming from you Pee off.

And you're obviously under the pump there as well Uncle Fester...