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Search found 374 matches

by BobbyB
Thu Nov 24, 2022 7:02 pm
Forum: Engine Tech
Topic: Cost to rev higher
Replies: 18
Views: 701

Cost to rev higher

Street/Strip SBC or SBF safely revs to 6000 rpm
How much more money and how much shorter life to build to:
Safely rev to 6500 rpm?
Safely rev to 7000 rpm?
Safely rev to 7500 rpm?
Safely rev to 8000 rpm?
by BobbyB
Wed Nov 23, 2022 7:45 pm
Forum: Engine Tech
Topic: How will you go faster?
Replies: 265
Views: 5697

Re: How will you go faster?

So many sims Stan I've lost track. Was that one the 470HP@6000 as an answer in another thread? Kevin, I believe that is the one I used see below. Note these graphs are for illustration purposes only as there are factor which can / will change these curve somewhat. One would need information about t...
by BobbyB
Wed Nov 23, 2022 2:17 pm
Forum: Engine Tech
Topic: How will you go faster?
Replies: 265
Views: 5697

Re: How will you go faster?

it looks to me like you should shift at 55 mph & 92mph to maximize acceleration ... Am I missing something? If you shift at 55 mph the acceleration takes a sudden drop from .76 g to .58, and the 3-4 shift drops .41-.33. If we had a complete power curve we should be able to do a lot better than that...
by BobbyB
Wed Nov 23, 2022 12:38 pm
Forum: Engine Tech
Topic: How will you go faster?
Replies: 265
Views: 5697

Re: How will you go faster?

David your own simulation data proves these statements incorrect. It does nothing of the sort. What do you feel is incorrect? Could you please provide a concrete example with real numbers? How is it possible your better calculated performance is with the lower of your chosen input parameters if the...
by BobbyB
Wed Nov 23, 2022 11:51 am
Forum: Engine Tech
Topic: How will you go faster?
Replies: 265
Views: 5697

Re: How will you go faster?

David_R_Accel_Gs.gif Many thanks to Stan for posting the graph. The G force vs MPH graph was developed from the torque curve furnished by Stan and the vehicle specs posted earlier. It shows the acceleration and speed in each gear. It includes transmission losses, air drag, and rolling resistance. W...
by BobbyB
Fri Nov 11, 2022 11:56 am
Forum: Engine Tech
Topic: Peak or area under curve?
Replies: 71
Views: 1638

Re: Peak or area under curve?

These issues are easily calculatable. We need the following information: Engine torque curve Weight Frontal area Cd Rear end ratio Gear ratios Tire rolling radius With the above information we can calculate acceleration and speed in each gear. Notice that horsepower is not a required input. That is...
by BobbyB
Thu Nov 10, 2022 4:31 pm
Forum: Engine Tech
Topic: Bill's SBF build advice
Replies: 65
Views: 1961

Re: Bill's SBF build advice

Scat 9000 crank, I beam rods and KB Hypereutectics would be fine for this deal. As far as the block, You would have to install ARP main bolts, tq to spec, and measure housing bores vs doing the same with the stock bolts. I'd bet money it's different, and out of spec. Plent of guys have just install...
by BobbyB
Sat Oct 08, 2022 1:39 pm
Forum: Engine Tech
Topic: This intake port mold really tells the story
Replies: 35
Views: 2449

Re: This intake port mold really tells the story

Ok, thanks anyway. When do expect to get them running on the engine?

Do you expect to make other changes before trying them?
by BobbyB
Fri Oct 07, 2022 6:48 am
Forum: Engine Tech
Topic: This intake port mold really tells the story
Replies: 35
Views: 2449

Re: This intake port mold really tells the story

But to the OP. The roof needs some luvin. I did take the curve out of the roof that you can see in the port mold before getting the head flowed. The roof contour looks more like your Profiler rendering. What volume is that port? Great job! Do you have a port mold of the head as it was flow tested?
by BobbyB
Sat Aug 27, 2022 7:41 am
Forum: Engine Tech
Topic: 383 sbc first dyno experience
Replies: 156
Views: 7745

Re: 383 sbc first dyno experience

Good job!
by BobbyB
Wed Aug 24, 2022 3:28 pm
Forum: Engine Tech
Topic: This engine is driving me crazy!!
Replies: 30
Views: 2048

Re: This engine is driving me crazy!!

Any news?
by BobbyB
Wed Aug 03, 2022 1:09 pm
Forum: Engine Tech
Topic: Questions about ports that stall, and cam lift.
Replies: 32
Views: 1336

Re: Questions about ports that stall, and cam lift.

I stand by what I posted. If a back cut increases reverse flow it WILL lose power. Simple as that. Let's qualify that ... what I have witnessed is IF that back-flow increases MORE than the air flow in the correct direction has increased from that back-cut, the engine will lose power. Most people wo...
by BobbyB
Sat Jul 30, 2022 9:19 am
Forum: Engine Tech
Topic: 383 sbc first dyno experience
Replies: 156
Views: 7745

Re: 383 sbc first dyno experience

For anyone interested, Have ran car over last few weeks. Had a run tonight. New 255/60/15 R series radials. Backed up cam timing 4 degrees so cam is straight up 109 - 109 . Car responded with a mph increase to where it should be . I have my 950 hp (750) back on as well,still rich will be taking som...
by BobbyB
Wed Jul 27, 2022 12:28 pm
Forum: Engine Tech
Topic: Holley Tuning Help Please
Replies: 41
Views: 1867

Re: Holley Tuning Help Please

https://www.speed-talk.com/forum/viewtopic.php?f=1&t=58672 I think the link above will take you to a very similar situation to what you are currently going through. My experience is that my BRAWLER 650 Vac Secondaries on my 347 ford acted much like you are seeing. It took a while for me to tune it w...
by BobbyB
Fri Jul 22, 2022 1:03 pm
Forum: Engine Tech
Topic: Octane additive
Replies: 49
Views: 2244

Re: Octane additive

Hemi aside, different head designs have different total of squish area. We have squish velocities but what could be the expected differences with different percentages of the air fuel under squish in the combustion event? Squish Velocity (SqV) will change with rpm, area ratio and clearaance. Same b...