Pump Gas Build some questions after dyno session..

Maybe you guys smarter than me could possibly see anything in this dyno sheet worth discussing.... Please ignore the air fuel ratio as i don't believe it was working at the time..

Anyway i read something i thought was interesting from a member on this forum recently " when a engine go's flat on power for 400 or more rpm it is smothering"....doesn't have enough exhaust duration to evac the cylinder.. At the peak rpm it starts this, the exhaust duration is maxed out".. could this be happening here?

Pulled the covers after the dyno.. didn't see any evidence of wagon wheeling on the valve tips...I'm assuming" ( not a good practice) it wasn't valve floating i could be wrong...I've read if an engine is still consuming air at peak rpm by the SCFM numbers on a dyno pull that it is usually not floating the valves..?

Ford Racing SCJ head 2.20 1.76 valves, Ti retainers, isky springs 235lbs seat 595lbs open..comp street solid roller 264 271 @ .050 689 698 lift 111 lobe..

i'm not a engine builder by any means only build an engine every 2 years or so for fun ..by the time i get round to the next engine i've forgotten half the stuff i've learnt   ..  any thoughts..?      

What's the rest of the combo?

Nothing to write home about Dave.. for the sum of it's part's Hp wise...
588ci 4.560 x 4.500 stroke
QFX 1150 dominator reworked by Competition Carbs..runs great on the street.
Ported plenum Victor, with jomar 1 inch tapered spacer.
standard tension rings 1/16 1/16 3/16.
Dynoed with Tri y headers 2" inch primary's, 2 1/4 intermediate, 3" inch collector not the best..only off the shelf ones available for the car.
runs on 93 octane here in Oz.. i'll attach another dyno sheet with the other details..

   

nascar429 wrote:Maybe you guys smarter than me could possibly see anything in this dyno sheet worth discussing.... Please ignore the air fuel ratio as i don't believe it was working at the time..

Anyway i read something i thought was interesting from a member on this forum recently " when a engine go's flat on power for 400 or more rpm it is smothering"....doesn't have enough exhaust duration to evac the cylinder.. At the peak rpm it starts this, the exhaust duration is maxed out".. could this be happening here?

Pulled the covers after the dyno.. didn't see any evidence of wagon wheeling on the valve tips...I'm assuming" ( not a good practice) it wasn't valve floating i could be wrong...I've read if an engine is still consuming air at peak rpm by the SCFM numbers on a dyno pull that it is usually not floating the valves..?

Ford Racing SCJ head 2.20 1.76 valves, Ti retainers, isky springs 235lbs seat 595lbs open..comp street solid roller 264 271 @ .050 689 698 lift 111 lobe..

i'm not a engine builder by any means only build an engine every 2 years or so for fun ..by the time i get round to the next engine i've forgotten half the stuff i've learnt   ..  any thoughts..?      

Not enough time to get the exhaust out based on cam specs. Loosen intake lash .004 and tighten down the exhaust lash about .010" after you get it in the car. It will be a different engine.

2 inch primary.. 2 1/4 intermediate.. 3 inch collector..  not terrible pipes but not great either.

Not enough time to get the exhaust out based on cam specs.  Loosen intake lash .004 and tighten down the exhaust lash about .010" after you get it in the car.   It will be a different engine.[/quote]


Thanks Chris i'll give that a go..that was you i was quoting probably figured that ..haha..

That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

nascar429 wrote:Nothing to write home about Dave.. for the sum of it's part's Hp wise...
588ci 4.560 x 4.500 stroke
QFX 1150 dominator reworked by Competition Carbs..runs great on the street.
Ported plenum Victor, with jomar 1 inch tapered spacer.
standard tension rings 1/16 1/16 3/16.
Dynoed with Tri y headers 2" inch primary's, 2 1/4 intermediate, 3" inch collector not the best..only off the shelf ones available for the car.
runs on 93 octane here in Oz.. i'll attach another dyno sheet with the other details..

   

Did you guys ever pull it low enough to find peak tq?

nascar429, this looks like a street driven deal to me....is that the case?

The Headers aren't helping the numbers.

Couple things I see, get some Jomar girdles for the heads (probably 10hp), what pushraods? and the jetting looks small with 87 mains IMO, need to get an AF meter and do some more tuning


Do the heads have any porting done?

It looks to me like all the support parts you have there are meant to be "right" with a smaller engine; A bigger engine will not make much more horsepower however, will make-up for it by giving a lot more torque below the torque peak.

Scott Foxwell wrote:That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

I agree about the intake valve size and headers but, I'm not sure about what you are saying about the Victor/Dominator thing.

Scott Foxwell wrote:That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

Thanks for your comments...I agree with you 100% the on the intake valve would loved to have fitted a bigger 2.25 in this head or a 2.3 intake in a p51 head but my friends budget wouldn't go there..

The headers are a compromise only one available for the chassis..unless he spent $3500 for custom headers that's the going price for custom headers here in Oz then $500 for coating.

the car runs a 1050 2 circuit on the street runs great it lost 10 to 12hp and about 8 ftlbs right through the rev range over the 1150 Dommy. we used as many parts from his old engine as possible just upped the cubes heads and cam etc..

Lem Evans wrote:nascar429, this looks like a street driven deal to me....is that the case?

100% street car full exhaust etc.. driven to club runs car shows etc for an hour at a time....10.99 quarter mile here means rollcage time he will race it just for fun next season hopefully..probably get told to bugger off after a couple of runs though not sure if he will ever fit a cage..

Would loved to have pulled it lower on the dyno but didn't on the day stupid really may of peaked earlier..

nascar429 wrote:Maybe you guys smarter than me could possibly see anything in this dyno sheet worth discussing.... Please ignore the air fuel ratio as i don't believe it was working at the time..

Anyway i read something i thought was interesting from a member on this forum recently " when a engine go's flat on power for 400 or more rpm it is smothering"....doesn't have enough exhaust duration to evac the cylinder.. At the peak rpm it starts this, the exhaust duration is maxed out".. could this be happening here?

Pulled the covers after the dyno.. didn't see any evidence of wagon wheeling on the valve tips...I'm assuming" ( not a good practice) it wasn't valve floating i could be wrong...I've read if an engine is still consuming air at peak rpm by the SCFM numbers on a dyno pull that it is usually not floating the valves..?

Ford Racing SCJ head 2.20 1.76 valves, Ti retainers, isky springs 235lbs seat 595lbs open..comp street solid roller 264 271 @ .050 689 698 lift 111 lobe..

i'm not a engine builder by any means only build an engine every 2 years or so for fun ..by the time i get round to the next engine i've forgotten half the stuff i've learnt   ..  any thoughts..?      

get a better header,and go back to the dyno, maybe a diff dyno

dfree383 wrote:The Headers aren't helping the numbers.

Couple things I see, get some Jomar girdles for the heads (probably 10hp), what pushraods? and the jetting looks small with 87 mains IMO, need to get an AF meter and do some more tuning


Do the heads have any porting done?

Thanks for the advice...the girdle is a good idea that i will do if budget allows..

the pushrods are 3/8 .80 thou wall ..I hated putting them in.. nobody sells thick wall pushrods here in Oz that i know of which is stupid.. custom .135 thou wall pushrods landed here would be $500..my friend would of choked if i told him that the whole engine has some compromises..due to a tightish budget.

The carb does have a powervalve in the front not sure if you noticed that for a street car tune.. i personally haven't been able to get a street car running well without a power valve in the front.. maybe squarer jetting and no powervalve would of helped on the dyno.
We played with the jetting and air bleeds to no avail.. bobby from Competition Carbs calibration seemed to be spot on for this engine with my limited experience..we did have some air/fuel numbers in early runs in the 12's from memory..

i'll attach a flow sheet the numbers around 300 to 400 thou lift intake..seem a little low for this head (SCJ) from everything i've read..this is out of the box and after bowl porting seat work etc..

rmcomprandy wrote:It looks to me like all the support parts you have there are meant to be "right" with a smaller engine;  A bigger engine will not make much more horsepower however, will make-up for it by giving a lot more torque below the torque peak.

That's exactly right alot of it was on his other 501ci engine...we robbed as much off it at the time to keep costs down...carb manifold sump dissy headers etc etc.. he wanted a 630ci+ and 750 to 800hp but that stroke is not practical in a street driven car in my opinion..so i talked him out of it.

he is happy with the power the engine makes and so am i to a certain degree for the sum of it's parts..of course i'd like to improve on it..I wanted a strong torque curve as his car is very heavy 3950lbs and mildly geared 3.7's 28 tire, he plans to race it ocassionally next season just to see what it can do..

Will make a few improvements when he can afford it, all the advice and knowledge that is given is thoroughly absorbed which is what this forum is great for.. so i can spend his and my money wisely in the future.

...

nascar429 wrote:get a better header,and go back to the dyno, maybe a diff dyno

If it was my engine i would for sure..because i believe some of the benefit of future mods will be downgraded with the poor pipes..but i don't think he will go for the cost of custom pipes at least $3500 to 4k coated on my side of the world..

We may change to a 3.5 collector.. though possibly that might be negated by always running a full length twin 3 inch to the rear with straight through magnaflows.

We will be testing on a chassis dyno in the near future..

Lem Evans wrote:

Scott Foxwell wrote:That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

I agree about the intake valve size and headers but, I'm not sure about what you are saying about the Victor/Dominator thing.  

Big engine with small heads/valves/exhaust...doesn't need a single plane with a dominator. Apples and oranges. I would bet a Performer RPM or Stealth with a 1000hp would make a lot more average power. Focus on the rpm range this engine is most efficient in.

nascar429 wrote:

dfree383 wrote:The Headers aren't helping the numbers.

Couple things I see, get some Jomar girdles for the heads (probably 10hp), what pushraods? and the jetting looks small with 87 mains IMO, need to get an AF meter and do some more tuning


Do the heads have any porting done?

Thanks for the advice...the girdle is a good idea that i will do if budget allows..

the pushrods are 3/8 .80 thou wall ..I hated putting them in.. nobody sells thick wall pushrods here in Oz that i know of which is stupid.. custom .135 thou wall pushrods landed here would be $500..my friend would of choked if i told him that the whole engine has some compromises..due to a tightish budget.

The carb does have a powervalve in the front not sure if you noticed that for a street car tune.. i personally haven't been able to get a street car running well without a power valve in the front.. maybe squarer jetting and no powervalve would of helped on the dyno.
We played with the jetting and air bleeds to no avail.. bobby from Competition Carbs calibration seemed to be spot on for this engine with my limited experience..we did have some air/fuel numbers in early runs in the 12's from memory..

i'll attach a flow sheet the numbers around 300 to 400 thou lift intake..seem a little low for this head (SCJ) from everything i've read..this is out of the box and after bowl porting seat work etc..

Based on the flow numbers and the CID, you won't be able to lash this thing enough to correct it. Valve size on intake being to small for build will affect the camshaft, but based on experience this thing will need about a 28 degree split between intake and exhaust at .050" to cam in correctly.

Scott Foxwell wrote:

Lem Evans wrote:

Scott Foxwell wrote:That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

I agree about the intake valve size and headers but, I'm not sure about what you are saying about the Victor/Dominator thing.  

Big engine with small heads/valves/exhaust...doesn't need a single plane with a dominator. Apples and oranges. I would bet a Performer RPM or Stealth with a 1000hp would make a lot more average power. Focus on the rpm range this engine is most efficient in.

I disagree, a 4150 and dual plane will kill this engines real performance running down the road .

Might appear better on the dyno below 3000 but will weeze out

[quote="dfree383"][quote="Scott Foxwell"]

Lem Evans wrote:

Scott Foxwell wrote:That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

I disagree, a 4150 and dual plane will kill this engines real performance running down the road .

Might appear better on the dyno below 3000 but will weeze out

WHERES THE LIKE BUTTON

dfree383 wrote:

Scott Foxwell wrote:

Lem Evans wrote:

Scott Foxwell wrote:That's a very small intake valve and very small headers for that many cubes. Kind of odd that you'd have a Victor intake and a Dominator.

I agree about the intake valve size and headers but, I'm not sure about what you are saying about the Victor/Dominator thing.  

Big engine with small heads/valves/exhaust...doesn't need a single plane with a dominator. Apples and oranges. I would bet a Performer RPM or Stealth with a 1000hp would make a lot more average power. Focus on the rpm range this engine is most efficient in.

I disagree, a 4150 and dual plane will kill this engines real performance running down the road .

Might appear better on the dyno below 3000 but will weeze out

It already weezez out. This thing is done at 6000 with these heads and exhaust and it's only using 1000cfm. No sense in trying to make it do something it doesn't want to do. Big dual plane and big 4150 would make this thing a monster from 3500 to 5500. It'll probably live it's life way more in that rpm range than above 6000. The single plane and dominator aren't doing anything for it down there and the engine isn't going to make any power where they would help.
Physics are physics.

Lem Evans wrote:

nascar429 wrote:Nothing to write home about Dave.. for the sum of it's part's Hp wise...
588ci 4.560 x 4.500 stroke
QFX 1150 dominator reworked by Competition Carbs..runs great on the street.
Ported plenum Victor, with jomar 1 inch tapered spacer.
standard tension rings 1/16 1/16 3/16.
Dynoed with Tri y headers 2" inch primary's, 2 1/4 intermediate, 3" inch collector not the best..only off the shelf ones available for the car.
runs on 93 octane here in Oz.. i'll attach another dyno sheet with the other details..

   

Did you guys ever pull it low enough to find peak tq?

This dyno sheet does not represent what you seem to be trying to accomplish with this engine / vehicle combination.
Personally, I would use dual-quads on a ported Blue Thunder intake manifold and let it make the most torque it can and have no worries about the horsepower above 5,500 RPM.