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 Post subject: Dynoing my 414ci SBC
 Post Posted: Fri Oct 30, 2009 11:51 pm 
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Planning to dyno test my 414ci SBC from the roadster before putting it in a dragster for next year. It's out and on the engine stand. Below is a list of whats in it. Looking for ideas of what to try on the dyno or suggestions.

My current thoughts on things to test ...
carb & timing - basic tuning, have jet kit and buying air-bleed kit before test
cam position adv-ret will check v-p clearance before test to know limits
vacuum pump I have a spare that won't be run in car but thought I'd try on dyno
carb spacer(s) - maybe open spacer
different carb? May be able to borrow one
pump gas vs race gas
valve lash

Thanks,
Rick


Engine Specs
Block - Bowtie CNC block
Bore - 4.125"
Stroke - 3.875"
Displacement - 414ci
Compression - 10.8
Crank - Callies Pro Magnum 4340
Rods - Compstar 6" steel rods
Pistons - Flat-Top Howards forged
Heads - Brodix Track 1X - ~ 310cfm
Intake Valve - 2.100" - 1.600" SS
Rockers - Shaft TBD
Intake Manifold - Hurricane Open Plenum I ported
Carb - 9375 Holley 1050
Cam - Comp Roller cam, (261/268 @ .050") .700/.650" lift w/1.65/1.55 rockers
Jesel Belt Drive


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sat Oct 31, 2009 1:31 am 
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I'd run the open spacer, and test Av-gas. The combo doesn't have much compression for the cam size and av-gas would probably be the best fuel. The dyno will have to have an AFR gauge at least or its no good going.


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 01, 2009 9:55 am 
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shrinker wrote:
I'd run the open spacer, and test Av-gas. The combo doesn't have much compression for the cam size and av-gas would probably be the best fuel. The dyno will have to have an AFR gauge at least or its no good going.


The dyno does have AFR indication and their dyno headers have the sensor built in, which should help in fine tuning the jets and air bleeds. I've never used O2 sensors before and always tuned for best ET or HP. Should help in getting the curve right.

The av-gas is a good idea. I used to run it exclusively. I still plan to run pump gas when racing but possibly a 5:1 blend pump to race or avgas. I am curious about the power difference.

Rick


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 01, 2009 10:54 am 
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When you dyno with that 3 circuit carb, pay close attention to AFRs off idle and thru the transition phase. Also, If you have problems getting it rich enough up top, then you already know why that happens. ;-)

Tuning with my O2 on gas shows AFRs around 12.5 to 12.8 make best power (MPH in my case). Idle and transition are up in the high 13s and low 14s which helps keep the plugs clean. Oh, and no, I haven't melted any headers off on the return road with those numbers! ;-)

Oh, and if you'll pay the round trip shipping, I'll loan you my 2 circuit 1050 for the session. ;-)

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 01, 2009 7:32 pm 
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Rick, I'll ship you my 2 circuit 1150 if you want to try it on the dyno......Oh and I'll pay the shipping =;

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 01, 2009 10:44 pm 
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Beretta wrote:
Rick, I'll ship you my 2 circuit 1150 if you want to try it on the dyno......Oh and I'll pay the shipping =;


BUT, MINE HAS ALREADY BEEN DEBUGGED! O:) 5.60 @ 127+ in 400 ft of DA and is fresh off the engine two weeks ago. In fact, it's still got gas in it. And Chuck has also run it on his PHord engine! =; And it's been on a POS 355 SBC, a 406 SBC and a 565 BBC and it did fine on all of'em! \:D/ But I'm NOT going to pay shipping! O:)

Heh, just horking with ya. BTW, those metering blocks (QuikFuel) Barry is using were on my carbie a couple of months ago, unless he's put the BLP blocks on it.

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 01, 2009 10:57 pm 
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I like the Idea of testing AV gas also.
Can't see any reason not to try it.

Since this is a bracket racing engine, I'd try different engine temps, to see how that may affect power, you know, late in the rounds when it's not quite as cool what will it run?

I'd also get a print out of all the dyno pulls. The jetting ones in particular. They may give you some indication as to how much the car will gain/lose ET, with a different DA.

May want to try a pull with whatever breather/hood scoop will be ran on the car.
See how that affects AFR.

Your looking for the most consistency, or lowest ET?

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 3:20 pm 
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Well it already has extended tip plugs, so that test won't happen. Won't be trying any other carbs either I guess. Avgas is on my agenda to try, but I doubt I'll go to the trouble of tuning the carb perfectly for it since pump gas is my plan for racing. I got some O2 bungs to put in my collectors and have a bracket made to mount the vacuum pump. Borrowed a set of 2" headers (I don't have any for my dragster yet) and have 2 different collectors, straight 3.5" and a pair of those tapered down venturi merge collectors with a choke size of 2.625" (from a small inch sbc making about 700hp). Found a 2" open 4500 spacer to borrow also.

I did get a full set of air bleeds to tune on the 9375 and checked my jet kit and plan to fill any open holes too before Wed (test day).

Any more ideas?

Rick


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 7:13 pm 
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Not sure how you could control it, but I think it would be interesting to do a pull at say 1500' DA, then change the air to 3000' by temp, and pull again, and see how close the power change is to HP corection factor formulas.

Then do the same thing, but change the air by baro.

Then by dew point.

Having actual measured HP from a dyno, at different air densities, would be valuable for a bracket engine.

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 7:40 pm 
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take your own timing light to the dyno ;)

change plugs ... mine made a decent difference

I am not a fan of pulling a motor on the dyno over and over, depends what builder ya ask but lots will say its hard on them to pull them a bunch .. remember that :-$

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 8:06 pm 
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Hammertime wrote:
take your own timing light to the dyno ;)

change plugs ... mine made a decent difference

I am not a fan of pulling a motor on the dyno over and over, depends what builder ya ask but lots will say its hard on them to pull them a bunch .. remember that :-$


Good idea on the timing light. I'll make a note. What plugs changed hp? new of same type? Different brand? I've never seen a plug do anything if you have a good ignition.

Dyno pulls don't worry me. It is MUCH easier on the engine than racing it. At 600rpm/sec pulling from 5500-7000 the engine only needs to be WOT for 3 secs. (.5s stabilize at start rpm and 2.5s run time). No burnout and about half the time of a 1/8 mile pass at WOT. This engine was built to race and designed with the intention of long maintenance intervals.

My last engine that I dynoed we did 22 pulls in one day from 6800-8500 or 7000-8700. It was alum rod, high comp, big springs and high rpm.

randy355 wrote:
Not sure how you could control it, but I think it would be interesting to do a pull at say 1500' DA, then change the air to 3000' by temp, and pull again, and see how close the power change is to HP corection factor formulas.

Then do the same thing, but change the air by baro.

Then by dew point.

Having actual measured HP from a dyno, at different air densities, would be valuable for a bracket engine.


I think some of the P/S or Nascar teams can actually do that. Nobody with my budget can do those tests. =; Seeing what the car does in different conditions and keeping good records should be sufficient.

Rick


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 8:07 pm 
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Any guesses as to HP and rpm? Closest will get a gift cert for the sum total of $.01

Rick


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 8:41 pm 
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I'll make a guess of 627 @ 6600 rpm.

Then I'll go run it on engine pro, and my be back to update my guess =;

It would be interesting for others to run it on other dyno software programs, and compare to real world results.

If others need info not posted about this engine, I'd bet Rick will post it. I don't think there's too many of his power secrets in this bracket engine.

What's the LSA, and where's the cam degreed in at?

Intake throat 89%?

Flow with intake on?

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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Sun Nov 08, 2009 11:25 pm 
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randy355 wrote:
I'll make a guess of 627 @ 6600 rpm.

Then I'll go run it on engine pro, and my be back to update my guess =;

It would be interesting for others to run it on other dyno software programs, and compare to real world results.

If others need info not posted about this engine, I'd bet Rick will post it. I don't think there's too many of his power secrets in this bracket engine.

What's the LSA, and where's the cam degreed in at?

Intake throat 89%?

Flow with intake on?


Power secrets??? :- No, none of those here.

Cam is 261/266@ .050 on 109LSA currently installed at 106. I should have room to advance the cam 2º more (4º if I'm really brave) and retard it as much as 8º. Looking at my notes from building it, the ex had .120" V-P w/no head gasket. This cam changes about .026" per 4º. I'll leave it where it makes the most/best power. The lift is ~ .700" intake and ~.650" ex.

Intake throat is 88.8% of 2.10" valve

Flow with intake (no carb) is ~ 305cfm peak (did not test all this way).

Rick


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 Post subject: Re: Dynoing my 414ci SBC
 Post Posted: Tue Nov 10, 2009 4:00 pm 
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One more thing about plugs, warm it up with a different set of plugs than what you plan to make the pulls on. There is no point in fouling the plugs while idleing..


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