Syed

Hey guys, i don't know much about superchargers and turbos but are they bad for your engine in the long run? I was told by a mechanic that superchargers and tubos are not good for engines in the long run because it wears the enigne out. is this tru?

Atrain

Listen...if properly tuned and with the right parts almost any engine can survive boost from a turbo or supercharger.

Look at a 2003-2004 Mustang Cobra...they come with a supercharged 4.6L DOHC V-8 from the factory. Granted the engine uses forged pistons, forged connecting rods and a forged steel crankshaft.

The 1989-1995 T-Bird SC used an Eaton M90 blower without exotic parts in the engine. Likewise, the 1989-1990 Mercury Cougar XR-7 did as well.

Then you have the 1999-2004 Ford Lightning truck...5.4L supercharged...again an Eaton M112.

This is just Ford...GM supercharged dozens of cars from 1990-present. Including the Cobalt SS.

Do they wear the engine out? No...they are compressors...they simply compress air and pack more of it into a smaller area. What wears the engine out is basic wear and tear, high rpms, knock, detonation, pinging, etc.

If the engine is tuned poorly and the wrong fuel is used, even a naturally aspirated engine can be damaged.

A-Train

againstallodds1

Off topic here.

Hey A-Train, how do you like that 4R70W tranny. I am either going with the 4r70w or a C4 with OD. Im in the process in looking at Lentech right now and also fbperformance. Let me know how you like it! thanks

Syed

man you know alot about cars atrain. it makes sense. i alsways hear turbo cars make that psss noise when shifting the gears its that compressed air.

Atrain

The T-Bird came with the 4R70W and in it's early years it did not have the Mechanical Diode Intermediate One-Way clutch (MD OWC) but rather used something similar to a sprag clutch with rollers on it. Those transmission were a 50/50 shot. If everything was inline with the centerline of the case then you would be fine.

If they alignment was off by just 0.005", then you would fail every OWC you put in the transmission. If you ran the transmission at high rpms in 3rd gear you could eventually spit the rollers off the clutch, but that is another story. Most failures had the transmission rebuilt and never changed the radiator. Guess where the automatic transmission fluid cooler is located? Yeap, in the radiator. So you would have a repeat failure later on. It doesn't matter if they flushed the radiator or not...you can't get all the particles out.

Those years of the 4R70W were terrible and it took a bad reputation for it. Starting in 1998, all 4R70W's received the MD OWC which is a rachet like clutch that stops the nonsense of the line-up with the centerline, plus it could hold more torque.

I have the original 4R70W in the T-Bird w/o the MD OWC. Here is what I did to it.

- 1999 Mustang GT main control (valve body) drilled by Jerry W.
- 1-2 Accumulator piston upgrade (all '98 have it)
- 2-3 Accumulator piston upgrade (all '98 have it)
- 2.7" OD servo (2.5" is stock) and new heavy spring
- Shortest reverse servo (adds 1 lb.-ft. of torque)
- 1996 pan and filter (prevents picking up air)
- Hayden 30,000 BTU plate cooler
- MERCON-V ATF (stock was MERCON-III)
- Various EEC-V changes to the transmission line pressure, etc. Done by Jerry W.

Those modifications allowed the 4R70W to handle 380 HP/440 TQ from the supercharged 4.6L. The tranny fluid is bright pink and never gives me any trouble.

The aren't all like this, but the 4R70W when treated with the right parts and care will last easily up to 450 HP. Beyond 450 HP you need to dig in and add parts and make changes that are costly.

Your 5R55S is based on the 4R70W slightly, but is not nearly as strong. I remember looking at the drawings and comparing them to the 4R70W in 2005.

I understand why you want to move to a different transmission. I suggest the 4R70W and I can tell you exactly where to look for a great build-up.

http://www.tccoa.com/articles/tranny...on/index.shtml

It's a great article by Jerry.

A-Train

Atrain

Syed,

The noise is most likely the blow-off valve. Turbochargers create lots of boost pressure. In between shifts the boost is bled into the atmosphere so it doesn't back up and pressurize the intake tube.

Here is the deal, boost is made when you flow air through a restriction. The more boost you have, the more cork in the inlet. I know this hard for some to believe and grasp, but boost does not equal power.

Let me show you an example...

There is a guy with a similar car set-up that I had on my T-Bird. We both used 1995 4.6L T-Bird's with ALLEN supercharger kits. This is based around an Eaton M90S supercharger and a water-to-air intercooler.

His engine used CNC ported and polished PI cylinder heads and PI camshafts. He had an "off-road" exhaust system consisting of no cats, headers, and two rear mufflers. Maximum boost pressure was 8-psi with a 2.25" diameter blower pulley.

My engine used stock PI heads and PI cams, no port/polish job. My exhaust used stock cast-iron manifolds, high flow cats, and three Borla mufflers. Maximum boost pressure was 10-psi with a 2.52" diameter blower pulley.

On the dyno he made 368 RWHP/400 RWTQ (SAE) with 8-psi of boost. I made 325 RWHP/380 RWTQ (SAE) with 10-psi of boost. Same engines...same day...same dynojet....same red color 1995 T-Birds...in fact...same EEC-V catch codes (H5T0) and same tuner (Jerry Wrobleswki).

Why did he make more power with less boost pressure? His engine flows more air and burns more fuel efficiently than my engine. Due to the ported cylinder heads and high flow exhaust he opened the cork up in the system and boost dropped. Power did not drop, but rather went up.

So clearly more boost does not equal more power. If it did, you could add 100 psi of boost and make 2,000 HP right? Wrong. You can only add so much air and fuel into the combustion chambers and compress the mixture.

A-Train

Atrain

Syed,

A quick run down of the differences between blowers.

All superchargers compress air and whenever you compress air you heat it. You cannot get around this...Thermodynamics law 101. Ever supercharger type has a different efficiency and range based on size and compression ratio.

1) Positive Displacement Superchargers: Commonly referred to as PD blowers.
PD blowers come in different types.

- ROOTS BLOWER: Roots type superchargers have straight cut rotors which move the same amount of air on each revolution. These blowers make tons of c.f.m. right off idle and pretty much until high rpms. The drawback of the roots design is there is NO compression occuring in the housing itself. Compression of the aircharge occurs as the air leaves the outlet and enters a different pressure (basically inside the intake manifold). Also the size of the compressor is often very large and cannot be packaged efficiently.

Look at any cake/egg mixer and spin it...that's the basic idea.





- HYBRID ROOTS BLOWER: Hybrid roots blowers...ONE WORD...EATON. Eaton is the largest manufacturer of hybrid roots design superchargers. There are also the largest supplier to OEM blowers for companies such as Ford, GM, Jaguar, Aston Martin, Nissan, etc.

Hybrid roots have twisted rotors or helical cut lobes that increase the efficiency and allow more c.f.m. of air flow.



The Eaton M90S has a 65% adiabatic efficiency at 4-5 psi of boost and 13,000 blower rpm. That means you can make a small V-8 feel like a BIG BLOCK with very little boost pressure. Plus you can turn it off quickly by just backing off the throttle and using the by-pass valve (built into all GEN-IV & V Eatons).

The downfall of the hybrid roots is the same as a roots blower. They generate lots of heat after they peak efficiency and is the number one complaint of Eaton owners trying to go beyond what the blower can produce. Take an Eaton M90S to 12-psi at 23,000 blower rpm and it will give you the same air flow at 10-psi but with 20 degree hotter discharge temperatures. Adiabatic efficiency drops to 50% at 10-psi. Half heat...half useful air flow.

Longevity of Eaton superchargers surpass 100,000 miles of trouble free service!

- TWIN SCREW SUPERCHARGERS: Twin screws are just what they sound like. Twin augers intermeshing together. Twisting and compressing air and the same amount on each revolution. The twin screws are the be all...end all of the PD blowers. Twin screws can move more air when compared to the same size roots blower just based on the fact that they compress the air in the housing before releasing it into the intake. This means they have an internal compression and higher adiabtic efficiency at high blower rpms.





The downfall of twin screws is cost (high prodution tolerances and aerospace bearings) and low rpm efficiency. A hybrid roots blower will walk all over a twin screw blower at low rpm low boost levels.

At 4-5 psi the Whipplecharger AX2300 is around 45% adiabatic. Lots of unwanted heat. Move the blower to 15-psi and adiabatic goes to 65% right where the Eaton M90S is...more air flow...less heat...more power. Increase the air flow and adiabatic remains the same.

This is why Twin screws are chosen when building race cars for the track or high HP is needed. Money is no object!

2) Centrifugal Superchargers: These type of superchargers spin an impeller inside a housing and compress the air as engine rpm builds. They work very similar to turbochargers. The main difference is turbos are driven off of exhaust gases and superchargers are belt driven from the engine.

Adiabatic efficiency of most centrifugal blowers is higher than hybrid roots blowers.
The largest problem with centrifugal blowers is they do not make air flow at low engine rpms. Unlike the P/D blowers they compress air based on rpm.



I hope this helps,

A-Train

ballinfizzle89

iTrader: (6)

A-Train-Wow haha you're a genius! Very informative!!

wizlb

I had a CT supercharger on my 04 TL and have a turbor on 96 skyline GTS-T boost 10PSI and I am telling you one thing and one thing only.
Its fun know mattter which one you have, just take care of you car.
I have moved overseas and its fun.

Syed

Thats a crazy lesson on turbos. Thanks alot atrain.

6spMike

To answer your original question, a supercharger or turbocharger does create more stress on the engine, that's how you get more power. More stress = shorter life.
If the engine is designed to handle the extra stress, it'll still last a long time.

jdmspec333

also, most factory forced induction has a lower compression ratio to deal with the boost. whereas their n/a counterparts have higher compression ratios. likewise, i would figure because of boost pressure and different compression ratios, forced induction engines have different pistons with thicker, stronger rings and ring lands.

fsttyms1

And that is why you typically dont go that high of boost on engines that werent built for it

Atrain

If you have forced induction you do not need (want) a high compression ratio. However, lower compression ratios yield lower power output.

Rule of thumb for V-8's is 8.8:1 to 9.1:1 C/R for forced induction.

6-psi on the 3.2L TL with it's C/R is sick!

A-Train

kenny_son

buddies 1992 integra with a stock B16 has about 230,000kms now...hes been boosted for like a year now..and his car stills runs great.

and he rips the shit out of it as well lol.

so ya, as posted above..with a good tune...they should be fine for awhile

Atrain

On my 4.6L V-8 I lost a piston ring land on the hyperpathetic (hypereutectic) piston. This was with 9-psi of boost. The boost and supercharger did not cause the failure...it was knock that rattled the piston. 21.5 degrees of spark timing on a 100 degree F. day was just enough to send it to death. Even on 100 octane unleaded gasoline this occurred.

These same type of failures have occurred on N/A 4.6L SOHC engines.

While blowers do increase the air charge compression ratio (not the static compression ratio) and add heat to the air charge, it is usually knock, detonation, etc that destroy the engine.

Hybrid Roots blowers that are driven from a single serpentine belt drive can sometimes yank hard on the crankshaft and wipe out the front main seals on some engines. As far as failures go...it is always due to state of tune or some uncontrollable event like the wrong fuel used (i.e. requires 93 octane and you use 87 w/o a KS).

A good engine build is a great idea, but keep in mind that even forged pistons and forged rods are NOT indestructible. I've seen enough professionally built race engines wiped out from simple detonation. I'll give you an example.

4.6L V-8 over 0.020".
Forged Mahle Pistons
Forged Manley connecting rods
ARP fasteners
WINDSOR block (deep skirt with a 4-bolt main and dowels)
Stock crankshaft
Ported/Polished cylinder heads
Aftermarket cams
Whipplecharged AX2300 blower (12-psi)
Water-to-Air intercooler (running ice water)

This car made 500 RWHP and ran 10's in the 1/4 mile at 130 mph. One one pass the engine detonated hard and lifted the cylinder heads off the block, pissing engine coolant into the engine bay. At the same time the shock wave flexed the crankshaft and wiped out the oil pump gears (fusing them together) and dropped the oil pressure to zero.

The engine used very expensive parts and was built by a professional (not a mom and pop shop or mail order engine builder) Randy Haywood. The crank was shot, one piston was damaged and the oil pump and gears were unrecognizable.

Did the supercharger do that? No...DETONATION did.

Can blowers and turbos lead to premature failures? Yes, they accelerate the wear when they are being leaned on.

Remember it's all in the tune and condition of the engine prior to forced induction.

A-Train

lifetimeofwar

Thanks for the info A-train. I always feel smarter when I read your posts hahah.

I hate cars

For most any motor, keep it out of detonation and it will live a long, healthy life. I had 220,000 miles on my old stock motor. The last few years it was running 11s with no mechanical failures. Only thing it had done was a new timing chain and valve springs. There were a couple times my 30psi boost guage was nearly pegged and this is with the factory cast pistons, rods, and crank on C-16 of course. Now pushing 602hp and over 620lbs of torque on the factory crank, block, and rods. Pistons are forged JEs and block is girdled. So far so good though this motor has a passion for killing transmissions. Won't even think of putting it on tire yet.

The first and only mechanical failure I had was actually with forged pistons. Broke a ring land on a set or TRWs from severe detonation but that was my fault. Too lazy to zip tie the vacuum line going to the wastegate. 30+psi on 91 octane didn't work too well.

More power will always mean more wear but with good tuning it shouldn't be an issue. Think of most diesels that are in boost just driving down the freeway and they last forever.