Don Terrill’s Speed-Talk

Thanks to all the kind words here. Been reading through this thread. The spreadsheet that I put together a while ago on tube size off the head to power level wasn't specific enough. My bad. There are several "other" parameters that also need to be taken into account and will force a chang...

Forgetting about mufflers for now, for that hp you need 3" dual at least down to your X pipe, 2.5" from there will 'just' support this hp IF it is a well made system. The X pipe is generally (not always, there are good ones), the most restrictive part of the system, so it is VERY importan...

Thanks to all the kind words here. Been reading through this thread. The spreadsheet that I put together a while ago on tube size off the head to power level wasn't specific enough. My bad. There are several "other" parameters that also need to be taken into account and will force a change...

AR devices act as diodes in a given system of pressure waves. If one could assign a percentage number to it's ability to reduce the "power" of pressure waves going through the device, (which we can't) but lets say 20%. Well that is significant isn't it? If you can reduce the amplitude (not...

I ran into Mr. Jenkins when the PS Truck guys started calling me. So I look at the port areas he was using, 1.88 was larger so that was what I used off the head. Built 421's, 1.88@13" (invoice says but they look longer!) and the secondary was 2.125 for about 5-6". The choke was 2.375"...

I have always wondered why so many people continue to run their vacumn advance off of Port vacumn instead of manifold. And even fewer know that it is possible to adjust how much advance they can have in their vacumn advance units...etc. Engines always like as much advance as you can deliver whether ...

Does anyone know if Calvin Elston is still open. I can't get a reply on his # (704-443-8088) DV Still at the same address in Matthews NC. google voice number is shown in my signature. Notice I took down my web-site. Don't need anymore work but still can and am building stuff if someone is persisten...

1972ho wrote: ↑Wed Oct 07, 2020 11:48 am Wow you are opening a thread that is 11 years old but I guess you see that.

Well ok, just saw this. I feel many folk can use a bit more reflection on "back pressure".

There is increased "backpressure" from a lot of things all pertaining to the ability to flow enough for the power level of the motor. Anyting added to a system like mufflers, running tubes to the back bumper etc can hurt the power level as it can not flow enough building pressure on the ex...

I just need to step in here. There is a world of difference between a 1.63 straight tube header and a header that leaves the head at 1.63 but is stepped and maybe many times to reach a given power level. A PS Australian 4into1 header may leave the head at 1.88" but it is stepped every 5 or 4 in...

oneaves2005 wrote: ↑Thu Jan 30, 2020 8:23 am Exhausted,

Just to clarify, are your suggested lengths from the valve or the flange face?

The exhaust port length is 2.8"

Ollie

Flange.

1000cc Superbikes making ~240bhp+ are using right around a 2.25" outlet... If you look at them closely, you'll see choke be almost the same diameter as the secondaries before tapering up in diameter from there (think a long slow expansion.. maybe 2" to 2.25 or so). I hear you Bob but the ...

I would question that long a header for that high a rpm band…

Late model Camaro's have turbo 2.7 litre 4 cylinder and 8 speed automatic. Also base engine in C1500 trucks. Lots of torque and relatively cheap and available.

It is probably the best bore diameter and stroke length/action for the most common valve diameters in American v-8's