Not your typical "pick my turbo" thread

[eastwoodad]

I currently have 81 Regal with a built N/A V6. I originally built this as a N/A car with the intention of modifying a centrifugal supercharger, but am contemplating a turbo. It has a single plane intake, Kenne Bell 2R cam (some specs in signature), forged pistons (9.25 to 1), 4.10 gears, and a turbo 350 with a 3400 stall converter. It is a turbo block, crank, rods, and ported heads with the big SS valves.

This is somewhat of a "run what you brung" type of car. I had the car, block, trans, and other parts and pieced it together. My question is, what turbo would best suit the car in it's current combination? I know changing gear/converter/cam would probably open up my options, but with 3 kids I don't want any more work than necessary. My plan is to source stock or aftermarket 86/87 headers and downpipe, but will be "blowing-through" a Holley carb. I was estimating roughly 15lbs or so, and am up in the air on intercooling (none, chemical, air/air, water/air). Oh yeah...and I dont want to spend the kid's inheritance on this...not opposed to used/knock-off parts within reason.

Any guidance would be appreciated.

 

[HUMBLE-U2]

HOW DEEP ARE YOURE POCKETS IF YOU HAVE A ENDLESS BUDGET GO TURBO.IF LIMITED BUDGET GO NOS FOR A FRACTION OF THE COST OF A TURBO CAR BUILD.

 

[WarWagon]

I remember you I can help. Humble has good advise too, you are already headed the right way in your thoughts about going blowthru. If you can source a set of stock headers and crossover and a down pipe at a decent price then just the turbo and carb and a good fuel system along with a wideband O2 are going to be the next biggest expense. Stick with a smaller turbo like a te44, 5857, te62, 6131 etc. It will be easier to get the carb in tune and you will have more run to run intake and charge piping around the distributor. As for intercooling, if you have E85 local do that or you could just run pump gas with an Alkycontrol kit. Probably dont need am intercooler but it helps but in your case its that much more charge piping to run plus more cash. I'd get a good wideband O2 before anything to tune with.

 

[eastwoodad]

I remember you I can help. Humble has good advise too, you are already headed the right way in your thoughts about going blowthru. If you can source a set of stock headers and crossover and a down pipe at a decent price then just the turbo and carb and a good fuel system along with a wideband O2 are going to be the next biggest expense. Stick with a smaller turbo like a te44, 5857, te62, 6131 etc. It will be easier to get the carb in tune and you will have more run to run intake and charge piping around the distributor. As for intercooling, if you have E85 local do that or you could just run pump gas with an Alkycontrol kit. Probably dont need am intercooler but it helps but in your case its that much more charge piping to run plus more cash. I'd get a good wideband O2 before anything to tune with.

@WarWagon...yessir, just getting the cobwebs off my car...haha. I slowly am getting reinvigorated with the car and am familiar with some of your blowthrough. N20 is the cheapest/quickest route, but just like the idea of the turbo better. No bottle to fill, and it is always there. Sure I am reinventing the wheel doing it this way, but I've been known to be hardheaded. Will the current gear and cam be detrimental with a TE44 or TE62? I would think too small of a turbo wouldnt be best as I would be out of its "powerband". And really would prefer not to do an air/air. Most likely nothing at all, or meth/alky kit.

 

[WarWagon]

You have the specs for the cam in your sig, whats the lobe seperation angle? It should still be ok for low boost and responsive being an exhaust biased cam grind, I know it has a rough idle I want a copy of it no ones makes that anymore. The gears are low but with tall tires could help more 373-323 gears and 27-28" tall tires. You said you only wanted to run 15psi of boost and no intercooler? You wont even need alky at this level. Stick with the smaller or stock turbo here, that low of boost on a bigger turbo is a waste and the response will be worse.

 

[charlief1]

His cam has a 110 LSA Adam. I remember when Aaron (sorry if I got it wrong) posted all his info before. I moved it to the B4black section since it makes better sense with a carb. How's the kiddo doing bud? Been a while since you've been here and I'm glad you're still sticking around.

 

[eastwoodad]

His cam has a 110 LSA Adam. I remember when Aaron (sorry if I got it wrong) posted all his info before. I moved it to the B4black section since it makes better sense with a carb. How's the kiddo doing bud? Been a while since you've been here and I'm glad you're still sticking around.

Thanks for moving this...debated posting it in both sections.

The kiddo"S" are great...and actually the 3rd is on the way in January. Been busy, right? All three are boys, so I am sure there are some racers in my future.

Warwagon-thanks for the info...I figured a stock or TE44 would be just about right. I *think* some friends of ours have a set of stock headers and possibly downpipe too. Would prefer 3", but maybe could get one made up cheap. This has become a race-only car for the most part. Has tags and insurance, but it is so cheap and it is nice to be able to legally test it out on the roads. Progress has been really slow on it with the family and all, but don't worry, it isnt going anywhere. Looking at weight removal methods now for cheap. Already gutted the bumper supports, no wipers/AC/power steering/etc. Would like to get it DEEP into the 14's NA. Just need some time....and help. Anybody in VA?

 

[charlief1]

You need to concentrate on the cars for your hobbies Aaron. Otherwise you're going to have a full race team when you're done.

 

[ek02]

The KB MK2R has a LSA of 108 degrees with 4 degrees of advance ground in. I have one in my spare 3.8. I wonder if it would work with a turbo? Turbo cams are usually ground at 112-114 LSA so the boost pressure does not go right out the exhaust valve. Warwagon, Comp will grind you that cam. I have the cam card if you need it. I also have a spare new SP108 from Poston, same specs as the MK2R. When KB stopped selling Buick parts, Poston had the cams ground by the same company KB used. This will be an interesting thread. A turbo will have more power potential than nitrous, I think, and be easier on the parts than the instant hit nitrous has. One question I have is on the header material. I always thought turbo headers needed to be built from stainless steel. Were the factory headers stainless or mild steel? Would heavy guage mild steel work with a turbo? If you use a blow through setup, what is needed besides a wide band O2 setup? Any way to use a knock sensor?

 

[bison]

Turbo cams are usually ground at 112-114 LSA so the boost pressure does not go right out the exhaust valve.

You might be surprised to find out that the lowest pressure you will have in the cylinder under power is the ex back pressure on any of these typical builds that will spool decently. This is the opposite of a supercharged engine. Therefore the intake mixture is what's getting diluted during the overlap period rather than the charge air going out the ex valve. Proper cam selection, CR and cam timing will maximize the potential at a given operating rpm. There are other things that effect the back flow too. Not running enough overlap will limit power running too much much and having the ex closing too late can cause loss of power also. Basically you want to have as much duration at .200" as possible and still get the valves closed at the optimal time. The fastest of the fast have this nailed down.

 

[ek02]

"Therefore the intake mixture is what's getting diluted during the overlap period rather than the charge air going out the ex valve."

Makes sense. I was under the wrong impression about the reason for the wide LSA on most mild turbo cams.

 

[bison]

"Therefore the intake mixture is what's getting diluted during the overlap period rather than the charge air going out the ex valve."

Makes sense. I was under the wrong impression about the reason for the wide LSA on most mild turbo cams.

The effect is basically lost duration. As the piston moves away from tdc the pressure differential allows flow through the int valve. You can't tell it's happening but it is.

 

[charlief1]

As bison kinda stated, it's a catch 22 here. If you'r really going for mid/low 10's or slower the LSA and overlap are different than one trying to go 9's or lower. The torque curve is at a different point as well as max RPM and HP. If you really just want low 11's or higher you need to load the exhaust so the turbo will spool better for low end but if you want the faster speed and quicker times it's a whole different ballgame.

 

[eastwoodad]

My thought was the higher compression (relative to factory) and the higher stall converter and higher numerical gear ratio would somewhat mask the fact the cam is not 100% ideal...however seems better than stock for drag only applications. I could also post up a copy of the cam card if anyone is interested.

 

[charlief1]

Go ahead and post all the info. That should help some.

 

[dr_frankenstein]

I gots headers, if you need em.

a stock turbo wouldnt be a bad place to start. particularly if you dont have a good carb bonnet. bonnet will make a world of difference in tuning.

dont forget to glue up the holley for boost. and boost reference it as well.

 

[eastwoodad]

I gots headers, if you need em.

a stock turbo wouldnt be a bad place to start. particularly if you dont have a good carb bonnet. bonnet will make a world of difference in tuning.

dont forget to glue up the holley for boost. and boost reference it as well.

Is their any more budget friendly fuel system than the Aeromotive A1000 series stuff? All the blow thru Mustang guys use that combo.

Here are the cam specs...

 

[charlief1]

Except for the LSA that's an almost perfect cam Aaron. Even with a 100% stock turbo set up that will make plenty of power.

 

[WarWagon]

Yes thanks for posting the cam card, I actually like the tighter LSA on that cam I believe it would be good with boost for being an NA cam.
The fuel system I ran on my blowthru wasn't too expensive and worked great and It supported nearly 400whp and 600wftlbs on N20, 300whp and 450wftlbs just boost.
I used an inline EFI booster pump (MSD 43gph) and a Mallory 4309 rising rate fuel pressure regulator, built a return style fuel system with the stock supply as return then connected it all with push lock hose. Probably a little over $300 if everything was new but you could sub some of those parts for cheaper stuff or get used.

 

[ek02]

I thought I had a KB cam card for the MK2R, but it was for a MK2. The Poston card I have for the SP108 has the exact same specs as the MK2R card above. This is a rough idling cam in a 3.8 if you have A/C. I had the same specs ground on the Comp roller in my 274". It idles very well at 850RPM in the bigger engine.