With the procharger setup my motor made almost 800hp at the crank (15#s) with fuel delivery problem, so with the turbo setup i could make the same power with a pound or 2 less boost easilly. And as a reminder my motor is built fairly strong, (half fill hard block, crower rods, federal mogul forged slugs, oil pan girdle) but the motor is fairly simple that anyone could build. Still stock block and crank of course, studs on heads and mains, stock heads gasket matched, small cam, and sp1....which made 443hp on motor. Theres a lot of people that have mild motors, or can easilly build mild motors like mine, but when you add boost it just becomes a monster. On my car i had no problem hooking at the track, stock type suspension, stock replacement springs, no air bags. The big key is the pinion angle, so get adjustabe uppers and lowers (uppers for pinion angle, lowers to center rear end where you want it) and it should have no problem hooking. My pinion angle was off so bad i was spinning all through first and into second with slicks running 7.4-7.5, the with the pinion corrected ran 6.9-7.0 with drag radials just barely but still cutting 1.55 60' with only a 2500 stall converter footbraking to only 1500.
In my feeble understanding, one of the best ways to do a blow-through setup and not have to mod carbs, it to put the carb in a sealed box where the whole box if fed by the turbo or supercharger. Then it works as intended, but its just operating in its own isolated chamber. That may not be worthwhile if your boost levels are fairly low, however. Or the carbs are easily modified.
Thanks a lot for the info. My current engine is a flat-top Hypereutectic piston engine, but it's got over 100,000 miles on it, and I'm just planning out my next rebuild. I figured that the kit would be $2400, but require another $5000 in hardware to run properly in addition to the kit. I"m currently building a big block for my truck, and I didn't want to put it in the skylark. So I think the twin turbos will be the route I take when it's time to freshen up the block and go through it again. I'll get low-compression forged pistons, port and polish the heads, and get the kit and all required hardware to make it bad ass. -Josh
The carb would still need to be modified because the air is still being forced through the carb. Anyone with a basic knowledge of carbs or can just follow detailed instructions can convert a carb that you allready have, but some of the aftermarket ones have a lot of features that can really help with tuning (mine self compensates, so if i turn the boost up or down, or going from summer weather to winter weather, i dont have to rejet or tune:TU link to modify your carb vvv http://www.hangar18fabrication.com/blowthru.html
I'm going to be doing a big single setup in a buddy's Olds Cutlass convertible soon. A GS would be the ultimate "fast with class" example!
it seems everyone is going away from the box and using a good quality hat csu extreme velocity, steve morris etc. I think from a stock ummoddeed carb the big box is more boost friendly however scince the blowthru carbs are getting so good the hat outruns it and is easier to work around
I don't know how I wave missed this tread for so long. But glad to see all of the progress. What Cam are you using. First off I have no leaning problems just over rich. This leads to my second point. I think that anyone who is going to install a turbo kit must include a good wide band O2 Gage to the total cost. I know that some of you are thinking yeah right you broke a piston that means you are lean. Well that is what I thought too. Untill I installed a good wide band O2 and it was crazy rich. After talking to some guys on the board who live in the boost world, they assured me that rich condition under boost can cause a motor to detonate. They have tested this on a dyno. And finally, I too have heard that if you put the carb in a box it eliminates the need for the boost referenced regulator. The big reason why opted to not go this route is because sealing the box and getting the throttle was something I did not want to deal with.
The extreme velocity hat and a few other aftermarket ones are a big step up from a box enclosre or cheep carb hat. The extreme velocity hat smooths out the airflow going into the carb, and has a divider in the hat to help smooth out the air even more which creates a more stable a/f mixture throughout the rpm and makes tuning easier as well. I run a one inch spacer between the carb hat and carb to help out even further, but it all depends on the amount of hood clearance you have. I have a 4inch cowl on mine but you could fit a smaller carb hat if you had clearance problems. With my 4inch cowl i have about 1.5 to 2 inch of clearance, but i run the sp1 intake, 1inch spacer under the carb, 1inch spacer above the carb, and then the carb hat. If you just ran a sp1 and carb hat you can fit under the stock hood.
TA 286-08H VALVE LIFT STOCK 1.55 RATIO: IN: .500” EXH: .504” TA ROLLERS 1.60 RATIO: IN: .516” EXH: .520” DURATION AT .050 IN: 234 EXH: 248 ADVERTISED IN: 286 EXH: 308 LOBE CENTER: 112 POWER RANGE: 2000-6000
STRAIGHT FROM VORTCHS'S WEBSITE (the one that came out with the carb enclosure box) "Also, a high-performance, boost referenced fuel pump is required."
did you spec this cam or is it a shelf grind? be interested to se how it works it is different that most turbo grinds the are usually single pattern or reverse split. i have a new spare custom turbo grind if you are interested later down the road good luck with the build:3gears:
This is just an off the shelf cam from TA it it worked out awesome with the procharger so i dont see any reasone why it wont work with the turbo, everything motor wise is staying the same. You dont have to use a big cam with forced induction so you just let the boost work its magic, and it also calms the cam down as well. Also i went with the split pattern to with more lift and duration on the exhaust side to help get all the exhaust out of the cylinder, it does bleed off a little boost on the low end but with my gasket matched stock heads i felt it was the best bet for me. Plus being quiet with that much power makes the car a real sleeper, no need for a big cam. 770 hp at 15#s on the engine dyno (procharger) without the carb being tuned (out of the box from quick fuel) and the fuel pump not being able to keep up ( at 5800 rpm it showed 4 psi, it needed 22psi)
Holy moly isn't that a lot of duration for a turbo cam? It will definitely create a lot of overlap even with the 114 LSA. Aren't you suppose to avoid overlap with a turbo cam?
