Can the 1988 2bbl 318 handle boost?

[8v-of-fury]

Looking at doing a blow through setup on the bone stock 120,000km 318 in my 5th.

Ive been thinking about this for years.. but the recent engine masters turbo 5.0 sealed the deal.

I likely wont use a used powerstroke turbo like they did, and infact use a better wheeled smaller turbo to keep the torque down low and hp under around 5000rpm.

The only difference i can see really between the 5.0 and this 5.2 is we may not have the forged bottom end they have.

 

[slant6billy]

I'm no expert, but I am going down the path of throwing some boost into a motor. Now, your 88 318 has 9 to 1 compression (likely if not all blowed by). So if you put way too much boost, you will grenade the motor. On the cheap, get some smaller turbos from a K car set up with blow off valves and all. I would suggest mocking them up like a ford ecoboost V6 with a turbo banked on the pass side and one the driver. See if you can get a small inner cooler or air heat exchanger . Heat is your power robber. Smaller turbos will spool up real quick and you will have great bottom end. You could do this on the cheap, since the k car turbos are still readily available. Now if you still want to get boost and turbo is not the path, there are supercharged Pontiacs with Sprint X superchargers from the late 90s and early 2000s. Nissan Path finder has a blower as well. Don't try looking for the Thunderbird supercoupes, they are money for parts. I'm going a different avenue with the supercharger. I like the look of the top mount Weiand 871, but it is almost impossible to get to the distributor for tuning. So the chevy kits for Powerdyne, Paxton, Whipple, and Pro charger will work on a small block non magnum mopar with some bracket mods. I'm holding out for a chevy guy to sell me used small block blower system. As for boost numbers I plan to go with 5 or 6 psi and once tuned go full tilt @ 12 to 16 psi of boost. I wouldn't be happy if I did not break something

 

[kkritsilas]

At 12 to 16 psi, on a stock engine, you will be very happy, very quickly, no matter the tune.

 

[MiradaMegacab]

How much boost?
The head gaskets are the weakest link

 

[kkritsilas]

Followed very quickly by pistons, and then conn rods .

 

[MiradaMegacab]

7000RPM and HydroLock did this damage on a 100,000+ mile stock lower end, with 6PSI of Roots boost AND a 150HP shot of N20.
The stock bottom end held together quite well under boost, IDK what I'd shift at as the tach only goes up to 8,000RPM and I'd bury it, quite often.

 

[8v-of-fury]

Thanks for the super reply's guys!

I'd be going for 10-12psi tops, intercooled if I can fit it easily, and never really expecting it to spin more than 6000 as an absolute RPM ceiling. They made that 5.0 make all of its torque between 3-4500 and the power was solid to 5500. I do believe this was on 15psi, so 10 should achieve numbers proportionately lower than this.. but still, goddamn. The amount of torque would make the wide gearing in the trans and high rear gear useful lol.

 

[slant6billy]

View attachment 22920 View attachment 22919 7000RPM and HydroLock did this damage on a 100,000+ mile stock lower end, with 6PSI of Roots boost AND a 150HP shot of N20.
The stock bottom end held together quite well under boost, IDK what I'd shift at as the tach only goes up to 8,000RPM and I'd bury it, quite often.

You Sir are one of my heros. Thanks

 

[MoparKidD-4]

That 5.0L Ford is a Mustang GT engine with EFI and a performance cam from the factory; starting out with a more HP-oriented engine like that definitely helped them achieve 550 HP. We know 14.7 psi of boost will theoretically double HP but if you're starting with only 150 you'll be making a whopping 300, and that's a lot of boost for a bone-stock 318 bottom end btw. IMO starting off with maybe 6 psi and working your way up to 10 or so is the safe/smart way to do it. Careful with the small turbo selection as well, a small turbo on a big engine will be inefficient and create a LOT of excess heat due to the massive backpressure on the hot side of the turbo system.

I've seen a lot of blown up engines from some local car guys slapping a turbo on some old stock high-mileage beater. The 318 is really tough but like was mentioned you would likely blow a head gasket, and it will probably lose ring seal pretty fast from all that extra combustion heat and pressure that those parts were never subjected to in the past. In my experience high-mileage engines don't like being souped-up too much, they start getting blowby and wear out quickly.

 

[kkritsilas]

The Mustang engine had forged components. Doezn't necessarily help with strength necessarily, but does help with heat resistance. Have a talk with any piston manufacturer, and see how many of them recommend cast pistons for forced induction engines.

Also, the Mustang engine was run on a dyno for what, 30 minutes? Far different from a car that will be driven regularly, or even semi-regularly. Even the discussion at the end was very careful to say what would be needed i a regularly used car. (Recollection seems to be around 8 PSI boost, intercooler, and maybe a dupercharger vs. turbo).

 

[MoparKidD-4]

The Mustang engine had forged components. Doezn't necessarily help with strength necessarily, but does help with heat resistance. Have a talk with any piston manufacturer, and see how many of them recommend cast pistons for forced induction engines.

Also, the Mustang engine was run on a dyno for what, 30 minutes? Far different from a car that will be driven regularly, or even semi-regularly. Even the discussion at the end was very careful to say what would be needed i a regularly used car. (Recollection seems to be around 8 PSI boost, intercooler, and maybe a dupercharger vs. turbo).

I wanted to make that point as well, I'm a huge Roadkill fan but they tend not to build their cars with longevity as a top priority as none of them get driven except for on the show and the breakdowns make the show more interesting and fun to watch.

 

[8v-of-fury]

I agree the 5.0 has a better starting point for sure, however I feel like the 2bbl 5.2 only makes 150hp because of the 2bbl and exhaust. Not because of the heads or camshaft. The intake is already a 4bbl and performer RPM, if the exhaust was real I'd bet I was more than the stock 150hp anyhow. If she makes 300-350hp and 525 lb/ft I'd be more than extremely pleased!

Stock 318 Hydraulic roller cam specs
Cam lift (int) .2489"
Cam lift (exh) .2669"
Valve lift (int) .373"
Valve lift (exh) .400"
Duration at .050" (int) 204
Duration at .050" (exh) 211
Lobe seperation 109

1987-88 5.0L - 211@.050 intake and exhaust, .444 lift, on a 115 centerline.

When I said smaller turbo, I meant smaller Not "small". One of a newer design and better suited to a 5.2 engine then just some random turbo of a 7.3 diesel. Luckily my engine is low miles and hasn't any blow-by I guess! lol I have experience with turbo vehicles, just not turbo'd Chrysler v8's savvy?

KKristilsa, I dig that. It is what I said in my first post. The only real difference I see between the 5.0 and the 5.2 is likely the smaller cam of the 5.2 and the non forged bottom end, basically.

Granted they usually don't give a hooot about their engines, this particular engine was from the Rotsun. The car known for literally doing nothing but having its ass beaten up and down the street. Will I subject my 318 to that? of course not ! lol However it is a semi-proven set-up still being owned by those guys in that car.. you must admit.

 

[kkritsilas]

My point was, that you said, in your original post, that you wanted to to 12 to 16 PSI. The 318 is a very rugged, very solid design, that was: a) not made to be force fed; and b) not a high output engine, from day 1, meaning adequate design for what it was intended to do and no further.

You can get good streetable horsepower in the 300-400 range out of a 318. There are tons of build up articles that tell you exactly how to do that (major points being compression and better heads). It probably won't cost much more that trying to get a turbo or supercharger to workm but it will be more reliable. as in day in, day out reliable. Trying to do that with a turbo or supercharger is not the way on a 318. It isn't just the bottom end, it is the heat that the piston crowns will be subjected to, it is the block/head design that wasn't designed to seal the pressures of forced induction. At 12-16 PSI, you will melt the piston tops, it isn't a probability, it is a guarantee. Finally, it is the bottom end.

You may be able to get away with 5-6 PSI. You most definitely will NOT be able to get away with it at 12-16 PSI.Factory equipped cars never ran those pressures stock, most of them (SVO Mustangs, Turbo T-Birds, Daytona Turbos, Buick Grand Nationals) only ran 8-10 psi, and that was with dedicated turbo engines. A few, like the Turbo T-Bird manual gearbox car, did allow short bursts of "over boost" to 12 PSI from the regular 8 PSI, but that was limited to a couple of seconds. You are talking about running 12-16 PSI on a 318, cast pistons and all.

 

[BudW]

MirandaMegacab do you have better pictures of your intake manifold – more specifically on where/how the upper radiator hose attaches to the intake?

I have considered this option for 30+ years but haven’t ever seen an intake thermostat that is friendly with the supercharger snout – so always blown off the idea (sic). I can’t make out details – but it appears this intake has been modified to work, possibly.

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I see on problem running a few pounds of boost on a high mileage and stock 318.

Start getting into the double digits of boost, I would highly recommend forged pistons, crankshaft and better rods (ie: a rebuild using better quality parts designed to run boost).

If I was going to do that, I would look for more inches (340 or a 360 engine).
If doing that, then I would consider a stroker kit (400+ ci).
If I was going to consider all of that – I might just skip the boost and run a 400+ stroker small block and be happy with that.

Wait a minute – I did consider all of that (while mumbling something incoherent about something being built out in the garage right now).
BudW

Edit: I have worked with a bunch of Chrysler 340 engines. Those engines are basically the same externally of a 318 – but internally they are nothing alike. Sit a 318 and a 340 crankshaft side by side and you can see the difference. You can also feel it when you pick both of them up – even though they “will” bolt in place of each other. The 340 was built, from factory, for high performance usage and you can tell. The 318 was built, not for high performance, but to be reliable engine (I think is the best way I can say it).

If I had a 318 (or bigger) that I was building up for the power (or boost) intended then I wouldn’t have any objection to running the current stock one as mentioned (boosted), sense a replacement is right around the corner.
That said, I wouldn’t take any risks on the boosted stock engine, without having a “Plan B”.

 

[8v-of-fury]

All very valid Kkritsilas, but the cost difference between the two is so great it kind of sways my hand you know? My second post said 10-12psi, not 12-16. I agree more than 10psi is pushing it. I can live with whatever power gains it produces in the end because it shouldn't cost me more than $1300cdn. Whereas heads, cam and headers will be likely end up costing 2-3x that much I'd think. 5psi would be achievable with a "physically" small turbo, just one with good turbine and compressor wheels.

I wouldn't be doing this for an all out power adder, more so as the most cost effeictive and labour effective way of making this engine have more than 150hp.

 

[BudW]

Unrelated. Diesel pickup turbos are kinda way too big for most cars to use.
The air intake tubes and intercooler on my diesel are 4” diameter and my exhaust (which previous owner modified) is 5” in diameter.

That means my 4” intake ductwork (without any boost) can flow over 1300 CFM and my 5” exhaust could flow over 2000 CFM (which is mute, sense the 4” intake - is the restriction).

I don’t think a 318 could ever flow 1300 CFM even if you took the valves out of it.

I saw that video of them using the Ford diesel turbo and started to laugh. Get something more size related and it would do a lot better.
BudW

 

[8v-of-fury]

Your cummins has 4" intake ducting? Granted they were not using a giant newer cummins turbo, they were using a 2.5" outlet turbo from an old Powerstroke. Do you believe your cummins moves 1300 + cfm? I don't think it moves anywhere near that.

I am not sure how much better they could have done over adding 272hp and 304tq lolol.

 

[MoparKidD-4]

Unrelated. Diesel pickup turbos are kinda way too big for most cars to use.
The air intake tubes and intercooler on my diesel are 4” diameter and my exhaust (which previous owner modified) is 5” in diameter.

That means my 4” intake ductwork (without any boost) can flow over 1300 CFM and my 5” exhaust could flow over 2000 CFM (which is mute, sense the 4” intake - is the restriction).

I don’t think a 318 could ever flow 1300 CFM even if you took the valves out of it.

I saw that video of them using the Ford diesel turbo and started to laugh. Get something more size related and it would do a lot better.
BudW

They at least got a smaller-size compressor housing when they met up with Gale Banks in one episode as per his recommendation. And the car originally had a 4.3L GM V-6, talk about MAD turbo lag but they also blew up 2 pf those engines before going with the 5.0L Ford.

@8v-of-fury has a point btw the 7.3L Powerstrokes were never considered powerhouses like the Cummins, they never made close to the same HP and torque even with updates from the factory; Cummins just kept leap-frogging them over the years and Ford realized they needed something drastically new, enter the controversial 6.0L... then 6.4... then 6.7... lol

The 7.3L was literally a school bus engine made by International Harvester/Navistar converted for use in a pickup truck application, whereas we all know the myriad of heavy-duty applications the Cummins was built to handle.

 

[kkritsilas]

8V-of-Fury:

If the idea is to have good power at minimal cost, find yourself a 360 Magnum, change the intake to a 4 Barrel, put on a Mopar electronic ignition, 360 car oil pan, add an electric fuel pump, and drop it into the M. The transmission bolts up, and factory rating was 275 HP. In addition, you get a serpentine belt drive, and roller lifters. Probably will come in at close to the $1300 range, depending on what you pay for the original engine. It will be quite streetable, have more power than you would imagine, runs on street gas, and the Magnum engines have both higher compression and tighter tolerances than the LAs of our cars. No hassles with rubo lag, ocstane boosters, etc.

 

[8v-of-fury]

I have toyed with that one for a while now - although messing around with the oil pan/timing cover fiasco as well as the motor mounts made me turn my attention away from that swap. I'd say it would be around $1000 just to obtain the vehicle/engine itself.. maybe make $200 back on scrapping the donor vehicle. so say $800, then add the $400 intake (maybe a carb too, unless they offer a spreadbore magnum intake, I don't know), the oil pan/timing cover dealio and then all the shipping/duties of Canadian living hahaha.

I'd have to find one hell of a smoking deal on a 360 magnum for it to be as cost effective. It WOULD be the most bang for your buck for sure, but how many bucks does one have is the question lol.

I find numbers of 245hp for the 5.9, at 9.1:1. My teen'r is also 9.1:1 and has roller lifters as well.

it's a damn tough decision to make, let me tell you.