2 heads better than 1 - power porting E7TE iron.

[Carnut1]

Next run gt40 aluminum heads ported by DV. A quick look and I think they will have more top end than mine but less mid range torque. The dyno will tell.

[PRH]

The air fuel ratio is nearly identical.

Okay........ so, 20#/hr more fuel, along with enough extra air to maintain the same A/F ratio....... with the result being a slight reduction in power.

I would think trying to figure out the reason it’s working out like that might be worth looking in to.

Obviously the bsfc numbers are going to be noticeably better with the combo that makes more power with less fuel.

OK, the fuel specific gravity was change after my E7TE heads were run so John's fuel numbers are more accurate. Thanks, Charlie

I guess the obvious follow up question would be....... was the fuel changed as well?

[travis]

60-ish HP better at 5000 rpm for both sets of heads and practically the same as stock at 2500, not too bad!

I’m curious why the stockers weren’t run past 5k like the ported heads? I’m sure they peaked but it would have been interesting to see the difference beyond the stock heads peak too.

[Carnut1]

Okay........ so, 20#/hr more fuel, along with enough extra air to maintain the same A/F ratio....... with the result being a slight reduction in power.

I would think trying to figure out the reason it’s working out like that might be worth looking in to.



Obviously the bsfc numbers are going to be noticeably better with the combo that makes more power with less fuel.

OK, the fuel specific gravity was change after my E7TE heads were run so John's fuel numbers are more accurate. Thanks, Charlie

I guess the obvious follow up question would be....... was the fuel changed as well?

All tests run on 87 octane fuel.

[Carnut1]

60-ish HP better at 5000 rpm for both sets of heads and practically the same as stock at 2500, not too bad!

I’m curious why the stockers weren’t run past 5k like the ported heads? I’m sure they peaked but it would have been interesting to see the difference beyond the stock heads peak too.

Small cam does not want to rev much more than that.

[Carnut1]

Next run gt40 aluminum heads ported by DV. A quick look and I think they will have more top end than mine but less mid range torque. The dyno will tell.

Resized_20181109_101053_9108.jpeg

DV ported gt40 aluminum heads 1.94"-1.54".
I thought DV got 270 cfm out of these but I and he is not sure of the exact number. He has all that logged at home. He did say the ports flow better than our E7TE's but they have a higher volume and lower port energy. Thanks, Charlie

[Carnut1]

60-ish HP better at 5000 rpm for both sets of heads and practically the same as stock at 2500, not too bad!

I’m curious why the stockers weren’t run past 5k like the ported heads? I’m sure they peaked but it would have been interesting to see the difference beyond the stock heads peak too.

I read this fast and did not answer correctly. The stock heads had the stock springs! Less load so less rpm before surge issues.

[PRH]

My interpretation of this last test is simply that the cam isn’t big enough to exploit the bigger heads.

These heads are also showing more fuel flow, and no more power....... showing same fuel s/g @.741.

I’d be interested in hearing the reasoning behind using the really short cam timing for this series of tests.

I also see it’s lost 10psi of oil pressure at the same 145* oil temp compared to a few tests ago.

[Carnut1]

My interpretation of this last test is simply that the cam isn’t big enough to exploit the bigger heads.

These heads are also showing more fuel flow, and no more power....... showing same fuel s/g @.741.

I’d be interested in hearing the reasoning behind using the really short cam timing for this series of tests.

I also see it’s lost 10psi of oil pressure at the same 145* oil temp compared to a few tests ago.

I have an issue with the short cam. I was told it would be a nasty hydraulic roller. It is not the cam he told me it was on the way up to Virginia. Intake manifold had a bit of a leak so we have gotten some water in the oil. Still issues with the 289 heads so I hope to test them tomorrow before I am forced to leave. Thanks, Charlie

[novadude]

What is the reason for such a tiny cam in this particular test? I may have missed it.

[jcisworthy]

My interpretation of this last test is simply that the cam isn’t big enough to exploit the bigger heads.

These heads are also showing more fuel flow, and no more power....... showing same fuel s/g @.741.

I’d be interested in hearing the reasoning behind using the really short cam timing for this series of tests.

I also see it’s lost 10psi of oil pressure at the same 145* oil temp compared to a few tests ago.

I have an issue with the short cam. I was told it would be a nasty hydraulic roller. It is not the cam he told me it was on the way up to Virginia. Intake manifold had a bit of a leak so we have gotten some water in the oil. Still issues with the 289 heads so I hope to test them tomorrow before I am forced to leave. Thanks, Charlie

I thought it was going to be an aggressive hydraulic roller cam also Charlie. The spring pressure on my heads are in the neighborhood of 160 seat and 4-425 @ .600 lift which is what I thought the cam was going to be around.

I would not have used those springs for this small cam

[Carnut1]

Yes, I made a note on the springs. Just compressing those spring ate a few horsepower. Thanks, Charlie

[PRH]

Or...... at the least, collapsed the lifters a bit and made the cam seem even smaller.

[Stan Weiss]

I like to have a visual / picture when comparing things.

Top Line Charlie

Second line down DV

Third line down John

Forth line down E7TE

Stan

ab-hp-302-test.gif

[RevTheory]

Right on. Thanks, Stan.