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The car will perform different when you put a hood on it. Those exposed TB’s at high speed see turbulence and act funny. Air will totally act different at the TB entrance when you get a hood on it and will affect performance for the better at speed.
Edit….There’s basically a vacuum effect happening at high speed over the TB’s…opposite of what you want.
Last edited by Che70velle; 03-10-2024 at 09:53 PM.
The car will perform different when you put a hood on it. Those exposed TB’s at high speed see turbulence and act funny. Air will totally act different at the TB entrance when you get a hood on it and will affect performance for the better at speed.
This was my thoughts and what we've been talking about. I also believe the car still has the strong mid range from the plenum volume and the direct path from each butterfly to port. I'm thinking the car will feel as strong or stronger once the hood is on.
The hi ram was being fed by a giant front duct right? Ram air vs open TBs perpendicular to airflow.
Results after the hood will be interesting, but until you feed it sealed air I'm not sure you'll get your fuel numbers back.
Do you have a MAP sensor in the intake? Were they reading any differently at speed?
I think the highway is your best dyno tbh you're dealing with some very dynamic conditions like Chevelle pointed out - you have acceleration #'s and fuel flow numbers. Assuming weather conditions aren't drastically different you should have a pretty good sense what is happening.
The car will perform different when you put a hood on it. Those exposed TB’s at high speed see turbulence and act funny. Air will totally act different at the TB entrance when you get a hood on it and will affect performance for the better at speed.
Edit….There’s basically a vacuum effect happening at high speed over the TB’s…opposite of what you want.
This was my thought as well. I saw an episode of Engine Masters recently where just adding a base for an air filter on a carbureted SBC picked up 5 or so hp on a 500 hp engine. So I think that air moving laterally across the top at 100+ mph could be creating a pretty decent vacuum inside the manifold.
You could try a forward facing hat or maybe a large filter element that covers both TBs. I could see how an air filter element slowing down the air could possibly help it transition down into the manifold. Maybe even block off the back side of the filter (the part closest to the driver) so that the area of low pressure from the drag it creates can't suck any air away from the engine.
The hi ram was being fed by a giant front duct right? Ram air vs open TBs perpendicular to airflow.
Results after the hood will be interesting, but until you feed it sealed air I'm not sure you'll get your fuel numbers back.
Do you have a MAP sensor in the intake? Were they reading any differently at speed?
I think the highway is your best dyno tbh you're dealing with some very dynamic conditions like Chevelle pointed out - you have acceleration #'s and fuel flow numbers. Assuming weather conditions aren't drastically different you should have a pretty good sense what is happening.
Yes, there is a map sensor in the intake. It's at the very back and very bottom. The hi ram was a few inches higher, at the back of the manifold, as well. I was seeing 98-99kpa, compared to about 101-102kpa with the hi ram.
Temperature was roughly the same. In the mid to upper 40s. Not on the same road, tho.
Hoping to get it on the dyno soon. I also removed all the spacers to see if that makes any kind of change.
Yes, there is a map sensor in the intake. It's at the very back and very bottom. The hi ram was a few inches higher, at the back of the manifold, as well. I was seeing 98-99kpa, compared to about 101-102kpa with the hi ram.
Temperature was roughly the same. In the mid to upper 40s. Not on the same road, tho.
Hoping to get it on the dyno soon. I also removed all the spacers to see if that makes any kind of change.
The MAP reading in isolation is mostly useless for this purpose. What you need is a log that compares the MAP with the Baro. The barometric pressure can swing from day to day, so what you're interested in is the ∆ between Baro and MAP.
The MAP reading in isolation is mostly useless for this purpose. What you need is a log that compares the MAP with the Baro. The barometric pressure can swing from day to day, so what you're interested in is the ∆ between Baro and MAP.
Andrew
Baro on the night with the hi ram was between 99-100kpa and MAP was 100-101kpa
Baro the other night was 100-101kpa and MAP was 98-99kpa
If your just driving the car on weekends or even less, I wouldn’t worry about the filters. Put a hood on the car that covers the TB’s by a couple inches if possible, and enjoy it. As you stated in a previous post, don’t drive in the desert and your golden. It’s not the type of build that your expecting to go 250k miles. It’s a race build that’s street driven, so rebuilds are on the maintenance list for sure. Plus you’ll make a few more ponies without filters. Now…if your gonna build something to direct air toward the TB’s, then you’ll want filters, but that’s different.
03-10-2024, 08:21 PM
