- Jul 28, 2019
- 690
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- #201
Well, picked up the last thing I needed to “tune” the fuel injection:
Wideband O2 sensor kit. Only way to calibrate WOT. A nice plus is it has a 0-5v analog out that my apu1 can accept for datalogging. That means I can just drive the car and download the log afterwards instead of trying to drive the car, watch the road, watch the rpm, watch the o2 gauge and somehow try to remeber what I have to adjust at what rpm. With the wideband, I just do a run, analyse the data, make my changes and do another run right away. With the “real time tuning” function of the apu1, I don’t even have to shut the car down to make adjustments.
Also, it appears I was making a GM performance parts intake from the lt1 intake manifold without even knowing it:
Thats a “ramjet 350” intake. It follows the old rochester mech fi manifold design, but updated for electronic fi. Sold by GMPP, Arizona Speed and Marine and as a marine intake for the marine GM 350 by Mercruiser. Essentially, its an lt1 intake with water crossover passages, a thermostat housing and a “pop up” roof.
Heres the dyno chart from the ramjet 350 crate package:
Just look at that torque curve! More like a table top than a curve! Around 360-375 lb/ft at 1750 rpm! Thats pretty much right off idle! And its still making 300 lb/ft at 5500 rpm! Cranks out 350 hp at 5200, which is about 4-500 rpm more than where the stock TPI lays down. He k, it makes the L98’s hp peak numbers at 3200 rpm and just keeps on going up from there. Even when it hits the L98’s “wall” at 4800, it stays a good 100-ish hp over the l98 all the way to 5500 rpm!
What a fantastic street engine! It should be one heck of a fun powerplant in my tiny c4 ’Vert!
Now, granted, that chart is engine dyno and likely NO accessories and headers out to atmosphere, but those are still numbers not to be taken likely. That should push a C4 deep into low 13’s in the 1/4, maybe even high 12’s.
The thing about the ramjet 350 is it’s just a plain ol’ 2 bolt main, cast crank, iron block, gen 1 sbc. It even has a cam with similar specs to the l98 cam (actually, its even a little “smaller” than an l98 cam).
The only appreciable difference from the l98 is the ramjet has vortec heads. The vortecs flow better than the 113 vette heads, but I’m sure I can port the 113’s at least close to the vortec flow numbers. The D-port aluminums actually arent that far off the vortec numbers @ 0.50 lift. L98: 193/161 vs vortec: 239/147. Exhaust already outflows the Vortecs. Intake kills the L98, but I’ve read of getting up to 239/192 with a good port job. Thats serious vortec (unported) territory...
wife ran into town today (her mom’s birthday) and picked me up some 6061 Al at the metal store while she was in there. Picked up a 2x8’ sheet of 1/8” and a four 1x1 1/8” wall square tube. Sheet is for the intake build, square tube I need for a few things on the argo.
I should be back to welding up the intake soon. I just have to sort out a few small details first, like rebuilding the egr and vacuum passages and I’m thinking of lengthening the runners a bit for more low end torque...
Wideband O2 sensor kit. Only way to calibrate WOT. A nice plus is it has a 0-5v analog out that my apu1 can accept for datalogging. That means I can just drive the car and download the log afterwards instead of trying to drive the car, watch the road, watch the rpm, watch the o2 gauge and somehow try to remeber what I have to adjust at what rpm. With the wideband, I just do a run, analyse the data, make my changes and do another run right away. With the “real time tuning” function of the apu1, I don’t even have to shut the car down to make adjustments.
Also, it appears I was making a GM performance parts intake from the lt1 intake manifold without even knowing it:
Thats a “ramjet 350” intake. It follows the old rochester mech fi manifold design, but updated for electronic fi. Sold by GMPP, Arizona Speed and Marine and as a marine intake for the marine GM 350 by Mercruiser. Essentially, its an lt1 intake with water crossover passages, a thermostat housing and a “pop up” roof.
Heres the dyno chart from the ramjet 350 crate package:
Just look at that torque curve! More like a table top than a curve! Around 360-375 lb/ft at 1750 rpm! Thats pretty much right off idle! And its still making 300 lb/ft at 5500 rpm! Cranks out 350 hp at 5200, which is about 4-500 rpm more than where the stock TPI lays down. He k, it makes the L98’s hp peak numbers at 3200 rpm and just keeps on going up from there. Even when it hits the L98’s “wall” at 4800, it stays a good 100-ish hp over the l98 all the way to 5500 rpm!
What a fantastic street engine! It should be one heck of a fun powerplant in my tiny c4 ’Vert!
Now, granted, that chart is engine dyno and likely NO accessories and headers out to atmosphere, but those are still numbers not to be taken likely. That should push a C4 deep into low 13’s in the 1/4, maybe even high 12’s.
The thing about the ramjet 350 is it’s just a plain ol’ 2 bolt main, cast crank, iron block, gen 1 sbc. It even has a cam with similar specs to the l98 cam (actually, its even a little “smaller” than an l98 cam).
The only appreciable difference from the l98 is the ramjet has vortec heads. The vortecs flow better than the 113 vette heads, but I’m sure I can port the 113’s at least close to the vortec flow numbers. The D-port aluminums actually arent that far off the vortec numbers @ 0.50 lift. L98: 193/161 vs vortec: 239/147. Exhaust already outflows the Vortecs. Intake kills the L98, but I’ve read of getting up to 239/192 with a good port job. Thats serious vortec (unported) territory...
wife ran into town today (her mom’s birthday) and picked me up some 6061 Al at the metal store while she was in there. Picked up a 2x8’ sheet of 1/8” and a four 1x1 1/8” wall square tube. Sheet is for the intake build, square tube I need for a few things on the argo.
I should be back to welding up the intake soon. I just have to sort out a few small details first, like rebuilding the egr and vacuum passages and I’m thinking of lengthening the runners a bit for more low end torque...
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