Inliners International Forums General Discussion Blown and Injected snowman4839 turbo build

So went and got a couple of new studs. The front stud is the 7/16 and the threads are nice and the stud holds strong. I just replaced that next stud because the nut was stuck to the old stud. Still gotta trim it.


Also because I was concerned with the rear stud strength and I just wanted peace of mind, I cross drilled it with this small bolt.


The bolt in the drilled and tapped hole


The stud with the cross drill and threading


The assembly all together and cross bolted.

Somehow missed your build but I am in the process(last 6-7 months or so) of putting together a 292 for turbo/tbi style injection. Shortblock is complete. Did you at all poke around the idea of a Borgwarner EFR series turbo for the twin scroll design and internal boost management?

Also, did you install steel top rings? The Ross pistons I purchased, when the machine shop looked up the part number, said they were cast. Any concern of shattering a top ring? Total seal gave me a reasonable price for the correct rings. I left .013 deck height with dished pistons and was concerned about 10 psi for a daily driver. Are you going back after 15 psi? Sorry for a bit of a scattered post and questions.

Btw, nice build so far. Everything is coming together great. A lot of attention to detail.

Thanks!

I didn't look too much at borg warner turbos. Mostly looked at turbonetics, comp turbos, and garrett. The garrett seemed was by far the best fit because I was halfwalf through fabricating another up pipe for the SPA manifold but I really wanted something that bolted directly to it because the up pipe was kind of a pain. I've only found that garrett makes reverse rotation turbos and that was the only thing that would work in this GM A-body that wouldn't hit the frame or control arms.

The BW turbos look nice enough but the SPA manifold has an external wastegate mount so I assumed I would make one anyway since that was how I did my last setup and I basically passed over any turbos with integrated wastegates.

Here are the rings that are in my engine at the moment.


and here are the clearances on the rings


I'm pretty sure the top rings are cast but I'd need to look up the part again. I'm not too concerned about the rings really. I put the first iteration of this engine through a hell of a beating and it only cracked out a ring/piston because it got to hot from going lean and those rings weren't gapped for a turbo motor. I guess I don't really know until it breaks but with a proper A/R ratio from EFI, intercooling, and a solid fuel system, I'd probably only get nervous once I start pushing past 15psi.

My plan is to run it at somewhere around 12-15psi daily. The chart below is where the efficiency of this turbo at different levels from a couple of pages ago. The first vertical line of a given color is at 3000rpm and the last vertical line is at 5000rpm. Between those lines is where I can expect the efficiency to be while I'm in boost. 10 and 15psi gives me pretty good efficiency in that 3000-5000rpm range which is likely where I'll be driving it. Once I get north of 20psi, I'll probably want stronger rods and to swap piston rings.


And thanks for the compliments

Isn't only half the manifold wastegated? I was under the impression the SPA manifold is a twin scroll manifold where only 3 cylinders are directly on the wastegate?

If you were interested, I got a quote for a pair of SCE ICS Titan copper gaskets. They will only make them in batches of 2 or more. It is ~.041 compressed with integrated O-ring and a 3.950 bore.

The new version of the SPA manifold has a center mounted wastegate but yes the old one had a side mounted wastegate.

This is the new one


this is what the old one looks like


I appreciate it but I've actually had good luck with the fel pro 1025 which has built in copper rings, the same compressed thickness, but a bigger bore.
https://www.summitracing.com/parts/fel-1025/overview/make/chevrolet

I'll be the first to admit I don't know much about this stuff. Gaerte Racing Engines is building me a blown 292. They tell me that 5 lbs boost is all I should run for daily driver on pump gas. Is a turbo different? I'm running a 292, 4-71 blower, billet crank, crank fired ignition, biggest valves they could fit and 3 roch 2 bbl. I don't know the specs on the internals. I build factories. So I guess my question is are turbos different as far as boost goes or am I missing something? Sorry if this is a dumb question.

Sounds sweet! There are no dumb questions! For a supercharger, that sounds about right. The main killer is going to be how hot the air you're blowing engine. Superchargers make low boost very quickly but they get quite hot as you start going around 6-8psi and up from what I've seen. Unless you have a air to water intercooler placed between your supercharger and your intake manifold (basically looks like a radiator) that your supercharger can blow the hot air through to cool it off, the added boost will be negated by the reduced timing you'll need to run in order to prevent your engine from knocking itself to death.

Turbos and centrifugal superchargers that basically look like belt-driven turbos (like prochargers) are different in that you can run piping to an air-to-water or air-to-air intercooler that you can sit in front of your radiator. This basically runs the hot compressed air through a radiator and keeps the temps nice and cool so it doesn't heat up your engine and pre-detonate (which has killed two of my short blocks so far).

Turbos can also be sized for your target boost pressure using those compressor map diagrams I posted in the last couple of pages. This ensures that you can track where your turbo will be most efficient at producing boost which means it will be adding less heat to the air in the first place while you're at full boost. This reduces the amount of work your intercooler needs to do since there isn't heat in the air in the first place.

The heat in the air determines the type of fuel you need to run which is why a supercharger (typically non-intercooled) can run 5psi on 93 octane because it's blowing some pretty hot air into the engine whereas an intercooled turbo can blow 15psi in the engine on 93 octane because the cooler air requires less octane to resist detonation. You just have the disadvantage of turbo lag.

IIRC, this is also why high power supercharged engines are typically used with alternative fuels like methanol or nitro because it takes a LOT more of those fuels (6.4 air to 1 methanol and 1.33 air to 1 methanol as opposed to 14.7 air to 1 gasoline) per combustion stroke of the engine. The basically means you're pumping 2.3x as much methanol and 11x nitro through an engine as you would gasoline. With all of this extra liquid running through the engine, it pulls a lot of heat out of the engine as well reducing the effect that the boiling hot air coming out of a supercharger would have on a gas engine making it feasible to run high supercharger boost with those fuels so you can get big power and fast power and throttle response without worrying as much about detonation.

This is the best video I've seen that demonstrates the effect of an intercooler. A guy setup an air temp gauge before and after an intercooler and you can see how crazy hot the air gets before the intercooler but it's kept at a nice 100F or so after the intercooler.

Thanks for explaining that to me. People here are so nice. I used to go to a different forum where some people were just plain rude. I went with the roots blower because I wanted the old school looks. This goes in my 53 1/2 ton Chevy pickup. I think 5 psi will be fine for me. BTW I have a Tremec TKO 600 5 speed and Frankland quick change rear end and Wilwood 12.88" disk brakes. 4 piston rear and 6 piston front. Thanks again for educating me.

Of course! I've had plenty of people on these forums help me along the way. Learning should never be discouraged.

Sounds like an awesome build. Would love to see some pictures of it. A blown or twin charged 250 is something that's been on my build list for sometime down the road. Just gotta get a bigger garage!

It seems nobody makes an intercooler for a 4-71 blower so I guess that settles that. I think it would be better even with small boost. Maybe someone could make it for me. I'm going to have to have an adapter plate made for the plenum and thought I might as well put the intercooler there. Maybe I'm overthinking this. Thanks again for the info. You got me thinking.

Between the compressor discharge and the manifold will work, but it's dangerous - full of combustible mixture, and a bad spark setting, hung valve or backfire will explode everything including the blower case.
The usual compromise is to have only air enter the blower case (GMC: on top, Eaton: in back), and the (pressurized) discharge pass through a remote intercooler (has to be in air stream, usually ahead of the radiator) which then supplies a "hat" over the carburetor's air horn. The bottom of the blower case can end in a simple box covering the whole bolt pattern and ending in a big tube passing sideways (to avoid the blower drive) then forward to the cooler.
A cheap intercooler is JY stuff or Chinese on eBay, some factory diesel coolers work OK. The piping to & from the cooler is typically 3" aluminum tube with rubber sleeves and screw lamps, no rocket science.
A Holley, Carter etc. 4 bbl. with the usual 5-1/8" top on a Clifford etc. 4 bbl. manifold will do nicely. It could blow through 3 X 2 bbls. but lots of extra work and you can buy all the 4 bbl. parts including a carburetor set up for blow-through.

It won't be as pretty, but more power with the same boost pressure.

Sorry mick, panic is totally right. The intercooled supercharger setups I'm thinking of basically require multi port fuel injection or any other type of injection where the fuel is added AFTER the blower/intercooler. Running a a charged mixture through an intercooler as you would with throttle body fuel injection or carbureted setups is not something I would consider very safe or really something I've ever seen. You should basically consider any part of the intake that has fuel in it a no-go for intercooling. It should just be heading directly to the heads at that point.

Thanks guys for answering my questions before I ask. With my setup now they have to make an adapter plate for the 4-71 to the I6 plenum. With a 3/4" plate my air cleaners will stick out of the hood about an inch. I was going to have them make the adapter about 3 or 4" thick. I figured if they were going to stick out I might as well own it and have them stick out 4". Maybe make a pyrex glass bubble for it. I also thought the taller adapter might help with fuel air mixing. My question was (a little late) can I just put the little radiator in the box. My next question was if the fuel would collect on it. Both questions answered quite well. I quit detonating things when I got out of the Navy. No intercooler for me. It will probably be fast enough for my old girl. It's nice to throw ideas out and not be ridiculed. Thanks again. I'm smarter today then I was yesterday. I'll learn to post pictures and show you what I've got so far.

I'm not the guy to ask about fuel/air mixing. That's a little beyond me and more of a dyno guy type thing to ask somebody. I'm having a hard time visualizing what you're talking about but would love some pics.

I'm not sure how far you've gotten or if you already have the supercharger purchased but I would look into manifolds from these guys if you don't want to do the custom on-off type setups for a lot of $$$.

http://www.aussiespeedshop.com/product/chevy-6-inline-supercharger-kit/

Also, I would suggest opening a thread like I have here for your build to centralize your thoughts and create a log of what you've done/are doing so you don't get them mixed up in threads like this.

On the plus side, the fuel passing through the 4-71 has a cooling effect as it vaporizes, so the charge temperature is actually lower than it would be if it were only pure air.
You can also use water/alcohol injected on top.

alright I got the engine painted. Gotta wait until it's a little sunnier and with a little less threat of rain before I can paint the accessories and start putting it back together.

Just after paint




With the valve cover masking removed. Looking good!

Got all the parts painted up! Should be able to get it all put together soon!

Got some of the the fan, pulley, and thermostat housing back on as well as the manifolds. The new threads/studs seem to work great on the two I stripped.





Completely forgot to paint stuff I pushed under the car *facepalm*. Still got the alternator bracket, starter bracket, and motor mounts to paint.

Snowman, is that Tom’s exhaust manifold?
I’m seriously struggling on whether to pull the lane 350 from my 55 Belair and replace it with a built 250 w turbo @ 15psi!

Mick - the Mazda Millenia used an air to liquid intercooler under the supercharger... I would think you could do a draw through supercharger and force the pressurized mixturethrough the cooling fins without an issue.
But, IMHO, I’d be going with meth injection. Nowhere as reliable, but far less complicated!

I believe it is. I bought mine off of ebay. It's the new design SPA 250 Turbo manifold. The link from Tom's website is below. Mine is the bottom with the wastegate under the center (new version) rather than the old one with the wastegate on the bottom of one of the exhaust runners (old version).

Still working on it guys. Work has picked up quite a bit and I'm moving into a new house in March or so (WITH A 3 CAR GARARGE :-) ). Chicago Winter is also going to slow me down and I'll likely pick it back up again in the Spring.

We are still waiting.