Drill out the converter fluid feed hole in the pump and thread it. Then install a pipe plug. The feed hole in the pump is normally around .250" and after installing the pipe plug you drill the pipe plug to between .150" and .187" to restrict the fluid flow. Apparently you may have to play with the dimension for your particular application to get it exactly right. This way, the trans gets the high line pressure it needs for the clutches and band to live and work correctly at the high HP level of a turbocharged engine, without the side effect of lowering the stall of the converter to the point where it the turbo is difficult or even impossible to spool. Also no need to loosen the converter and create more heat in the trans fluid, which is already a big enough problem in the trans of a turbo car.
Advancement of fuel delivery?
- Thread starter Alky V6
- Start date
Drill out the converter fluid feed hole in the pump and thread it. Then install a pipe plug. The feed hole in the pump is normally around .250" and after installing the pipe plug you drill the pipe plug to between .150" and .187" to restrict the fluid flow. Apparently you may have to play with the dimension for your particular application to get it exactly right. This way, the trans gets the high line pressure it needs for the clutches and band to live and work correctly at the high HP level of a turbocharged engine, without the side effect of lowering the stall of the converter to the point where it the turbo is difficult or even impossible to spool. Also no need to loosen the converter and create more heat in the trans fluid, which is already a big enough problem in the trans of a turbo car.
That mod sounds real familiar. I didn't realize it was a 'Neal Chance mod'. I guess people are starting to call the mod their own now?
I've been doing a similar mod for close to 20 years on 400s for any application from stock to race. One exception though. .150" to .187" is much too large of an orifice. This mod also keeps the crank thrust of BBCs alive.
Use .110". I've used that size since the beginning with no ill effects, ever.
To answer your question Scott, I restrict the T/C feed passage to .110" (7/64") on every 400 I build, no matter the application. So the mod has been done to the 400 I run in my car from the beginning.
As far as this new mod, after I've done more testing, I'll let you know. So far, all I've done are short stall tests. The stall speed does flatten out at 2820 rpm. It doesn't keep climbing. Under continual load throughout the rpm band is the next test.
I've been playing around with the 60ft sim. I'm amazed by how much more hp it takes to move from a 1.69 to a 1.54 60 foot.
There was one point when I first started tuning in the boost transition on the fuel map when I did clock off a 1.55 60 foot. At that time I didn't realize how important that particular tune would be. If I remember right, that was when the nitrous hit was still reading pretty lean. I'll have to go back through my records and try to find that timeslip and tuneup.
I found 2 timeslips. A 1.567 and a 1.556, a couple weeks apart back in August. One of the slips has the calibration file name scribbled on it! Cool.
There was one point when I first started tuning in the boost transition on the fuel map when I did clock off a 1.55 60 foot. At that time I didn't realize how important that particular tune would be. If I remember right, that was when the nitrous hit was still reading pretty lean. I'll have to go back through my records and try to find that timeslip and tuneup.
I found 2 timeslips. A 1.567 and a 1.556, a couple weeks apart back in August. One of the slips has the calibration file name scribbled on it! Cool.
With methanol, there is a sweet spot mixture where flame speed and temperature of combustion are at their highest. In either direction, rich or lean of that sweet spot, temps and flame speed drop off and there is less tendency to get in trouble with pre-ignition. In the past, I tried to make sure I was always on the rich side of the sweet spot. It looks like I'm going to have to go back through my multitude of datalogs to pin point the sweet spot mixture. I recall some launches where I did get some lean backfires. I'll start with those.
The sweet spot looks to be around 12.96 - 13.67 on the readout. That would be an actual methanol to air ratio of 5.71 - 6.02:1. Stoich for methanol being 6.45:1.
On the top end I'm running at 4.58 - 4.80:1.
I'm going to start leaning the nitrous region of the fuel map and shoot for no leaner than 5.37:1. That will be a readout of 12.2:1. I'll be paying attention to map and rpm rise rate and the 60ft times as I work leaner.
If I don't make it, call my wife... Going in!
On the top end I'm running at 4.58 - 4.80:1.
I'm going to start leaning the nitrous region of the fuel map and shoot for no leaner than 5.37:1. That will be a readout of 12.2:1. I'll be paying attention to map and rpm rise rate and the 60ft times as I work leaner.
If I don't make it, call my wife... Going in!
You know it! Junks got to be broke to miss a test and tune. The last chance to test before the Summit Series Finals at Firebird in Arizona.maybe another black buick there too!
doing some sorting out.
Hope to see you there.
Yeah. I know what you mean.
A slow start with a big top end makes for a good bracket racer though.
No, it makes a good title winner.:biggrin:
Title winner? Ya lost me Charlie.
LOL Donnie, I used to race for titles with my old car. No one believed that a V6 Skyhawk could blow their sh!t away and I used to make money selling their cars back to them. Love watching them try to find a nitrous bottle in the car and I never used one.:biggrin:
Not much to tell now Donnie. 76 Skyhawk with a Rhere and Morrison built engine. I did my home work at the time and they did the Indy engines so they did mine. Started with a 4 speed and switched to a 5 speed with a 3.42 rear because I blew the factory 2.92 out the back on a launch, literally. The ring and carrier cut through the tank and was a big mess. All the kids thought their camaros and mustangs were fast and when they saw my little Hawk with V6 badges and a rocking vibration when it idled they thought I had a V8 BB in it until I opened the hood. They'd laugh and it was on. Loved the look on their faces when they handed the title to me, signed and ready to go for registration. Still have her but she needs a tube frame to be safe now. I warped the unichasis so bad it aint even funny. the engine is ruined now because I left her with a "friend" and it got stripped. I may try to resurect her one day but right now I have enough to do with the 82 so she's on the back burner.
The strange thing about this new mod is, this was just a preliminary step towards a much more complicated final modification. The results of this first minor step was a complete surprise. The idea was to make sure the idea wasn't going to fall flat on its face before spending the time to do the full monte with it. If this also translates into any change at all in the launch (for the better, hopefully), I'll be a happy camper.
After going back to work on the 60ft sim, I found that to accomplish a 1.55 60ft with no assistance from turbocharger boost would require the methanol/nitrous hit to start out at close to book value (320s), but would then immediately drop to around 2/3 (200) of the present nitrous jet size hp rating. This shows how important the n/f ratio is with methanol.
The target of 10.9:1, which is just fine if not a little too lean on the top end, on the nitrous has proved to be too rich. It is over cooling the intake charge and combustion process. Had to find out. Time to work back towards lean on the nitrous.
Timing when on the nitrous will start out at 15 btdc at initial hit working to 21-22 btdc by the end of the hit.
The target of 10.9:1, which is just fine if not a little too lean on the top end, on the nitrous has proved to be too rich. It is over cooling the intake charge and combustion process. Had to find out. Time to work back towards lean on the nitrous.
Timing when on the nitrous will start out at 15 btdc at initial hit working to 21-22 btdc by the end of the hit.
Mid 80's Don. We had a side road everyone in DFW used to run and the high school kids would show up and thing they were hot stuff so we used to bust them all the time. Miller brewery road was a lot of fun back then. Ok, done with the temporary high jack. lol
I'm wondering if there's some way to heat the engine up a little more for better combustion. You may not have to cut the nitrous down that way and get more power.
I'm wondering if there's some way to heat the engine up a little more for better combustion. You may not have to cut the nitrous down that way and get more power.
It would be better to preheat the intake charge itself rather than heating the engine inorder to heat the charge. I don't see any easy way of doing that with the way the engine is setup. Everything is port injected with a very short distance before entering the cylinder.
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