I was wondering what the limit (normally aspirated) is interms of the s38b35, M88, and the s38b38. If you could maybe add the tq factors and RPM for peak power. Those previous requests aren't necessary, I'm just looking for a ball park figure.
TIA
Justin
Just Curious About the Max Power output....
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Tammer in Philly
- Posts: 10719
- Joined: Feb 12, 2006 12:00 PM
- Location: CHI, IL
Well right up front, I don't know about limits. The S38/M88 is a pretty high-strung motor, and I don't know how much more room there is to play with within the safety envelope. The S38B38 is rated at 340 hp stock, and it has some specific wear/durability issues. The S38B35 has the crank-hub issues, which were solved on the B36 and B38 by a 4-bolt design. The intakes changed over time as well, which leads me to believe there are inefficiencies in the B35 that could be improved.
That said, I have picked up that the S38 motors respond better than almost any other motor to the simple addition of a chip; probably for emissions reasons the US market S38s were mapped very conservatively. So the standard chip/intake/exhaust mods will get you north of the M88's rated 286 hp (my dyno sheet, stock w/ Jim C chip, shows 250 rwhp on a Dynojet). I need to scan that sheet, I keep forgetting.
-tammer
That said, I have picked up that the S38 motors respond better than almost any other motor to the simple addition of a chip; probably for emissions reasons the US market S38s were mapped very conservatively. So the standard chip/intake/exhaust mods will get you north of the M88's rated 286 hp (my dyno sheet, stock w/ Jim C chip, shows 250 rwhp on a Dynojet). I need to scan that sheet, I keep forgetting.
-tammer
when considering the S38B38, the improvements over the S38B35 USA include:
- cams
- compression
- redline
- displacement
- exhaust headers
- variable volume intake
- coil packs
- newer Motronic
- larger valves
- larger throttles
- better crank hub
With that done, you take the motor from 256hp to 340hp.
What do you suppose is left without going to race-spec stuff? Things left are
- more displacement? (the original M1 blocks were 4 liters)
- more revs?
- more compression?
- more chip?
Note that cams, headers, CR, and lack of catalyst gave you 30hp in the S38B35 Euro over the S38B35 USA.
I'd have to assume a race-spec S38 can get more than 400hp if the street motor S38B38 can do 340 stock.
The m1 procars got 450hp or so on 1970s technology.
- cams
- compression
- redline
- displacement
- exhaust headers
- variable volume intake
- coil packs
- newer Motronic
- larger valves
- larger throttles
- better crank hub
With that done, you take the motor from 256hp to 340hp.
What do you suppose is left without going to race-spec stuff? Things left are
- more displacement? (the original M1 blocks were 4 liters)
- more revs?
- more compression?
- more chip?
Note that cams, headers, CR, and lack of catalyst gave you 30hp in the S38B35 Euro over the S38B35 USA.
I'd have to assume a race-spec S38 can get more than 400hp if the street motor S38B38 can do 340 stock.
The m1 procars got 450hp or so on 1970s technology.
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Mike M5 in UK
- Posts: 9
- Joined: Feb 12, 2006 12:00 PM
from a current UK e-bay E28 M5 advert
"I have a full stainless steel exhaust system from a company called fritz bits in Somerset, they specialize in m3 m5 and m6 performance parts and the exhaust I bought combined with an up rated air filter takes the original horsepower from 286 to around the 328 mark, since fitting ive had a very good increase in power and better fuel consumption it runs absolutely faultless, both engine and transmission is spot on."
great thing is fritzbits is about 20 miles up the road from home
a header question: if bunch of snakes euro exhaust only adds 5 bhp over plain straight pipes but costs a whole lot more - why did BMW bother?
should you gettoSpain and see a black M5 stand clear - apparently the Spanish internal security - or one of the sections that is beyond day-to-day policing use black M5s - mine E28 came from Spain so maybe.....
"I have a full stainless steel exhaust system from a company called fritz bits in Somerset, they specialize in m3 m5 and m6 performance parts and the exhaust I bought combined with an up rated air filter takes the original horsepower from 286 to around the 328 mark, since fitting ive had a very good increase in power and better fuel consumption it runs absolutely faultless, both engine and transmission is spot on."
great thing is fritzbits is about 20 miles up the road from home
a header question: if bunch of snakes euro exhaust only adds 5 bhp over plain straight pipes but costs a whole lot more - why did BMW bother?
should you gettoSpain and see a black M5 stand clear - apparently the Spanish internal security - or one of the sections that is beyond day-to-day policing use black M5s - mine E28 came from Spain so maybe.....
Unless the euro factory exhaust is uncharacteristically bad garbage, Fritz is full of sh@#4t. There are no exhaust + air filter options that add anything besides noise to a stock US M5. I suspect the euro car is similar.
The US manifold was dual 3->1 "logs". The euro manifold was a proper "bundle of snakes". The manifold, higher CR, and better cams constituted the 30hp difference between the USA S38B35 and the Euro S38B35.
I don't know where the 5hp figure comes from.
The US manifold was dual 3->1 "logs". The euro manifold was a proper "bundle of snakes". The manifold, higher CR, and better cams constituted the 30hp difference between the USA S38B35 and the Euro S38B35.
I don't know where the 5hp figure comes from.
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Rich Euro M5
- Posts: 6098
- Joined: Mar 10, 2006 6:20 AM
- Location: Klein, Texas
[QUOTE="Matt"]I don't know where the 5hp figure comes from.[/QUOTE]
The 5 HP figure comes from someone on this side of the pond that performed Dyno pulls of his E28 M5 at specific points during his upgrades. IIRC, Dyno pulls were done with the stock exhaust manifolds, then after installing the Euro snakes, no other mods and the snakes yielded a 5 HP increase over the stock manifolds.
Rich
The 5 HP figure comes from someone on this side of the pond that performed Dyno pulls of his E28 M5 at specific points during his upgrades. IIRC, Dyno pulls were done with the stock exhaust manifolds, then after installing the Euro snakes, no other mods and the snakes yielded a 5 HP increase over the stock manifolds.
Rich
I know the guys at FritzBits...tell Rich I said hello...
They are all about their 6 branch manifolds, headers, but that does sound like a big gain from just headers....
There is one shop that claims they are getting around 425hp out of a tricked out s38b38.... I forget their name...he rents tools out sometime?????
They are all about their 6 branch manifolds, headers, but that does sound like a big gain from just headers....
There is one shop that claims they are getting around 425hp out of a tricked out s38b38.... I forget their name...he rents tools out sometime?????
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Adam W in MN
- Posts: 5052
- Joined: Feb 12, 2006 12:00 PM
- Location: Don't waste my motherf***in' time!
- Contact:
S38b38
The issues with the S38b38 as far as I know from owning one for a year now and reading a lot on the E34 M5 list(s) concern the rod bearings. They are thinner than the S38b36. In my opinion the S38b38 is on the edge of the design envelope but that doesn't mean it's an unreliable motor. I think that it leaves little margin for error from stupid owners. When I had the rod bearings in my '94 E34 M5 3.8 replaced at 51K original miles they were in poor shape. A guestimate said maybe in another 20K miles I would have spun a bearing. The S38/S14/BMWCCA guru who did the job theorized that the car was given some low octane fuel at some point, maybe the owner in Germany romped on it when the oil temps had not come up yet, and also possibly from sustained high revs at autobahn speeds. I always let the oil temps come up before shifting above 3K rpm with the car. I run dead dinosaur oil in there and not synthetic (cuts down on S38 oil leaks).
I'm running a chip in mine that is supposed to do a decent performance bump. I have not dynoed my car to verify, but other S38b38 owners with the chip are doing between 300-310 at the rear wheels. With some uprated cams, a more agressive chip (and strict adherance to higher octane fuel) and a few other tweaks, I think you could see 400 horsepower out of an S38b38. I would guess that is about the limit for street reliability and natural aspiration. That's not based on expert opinion, just from what I've read and seen on the E34 M5 list.
I don't know why, but the howl/shriek of the S38b36/S38b38 motors at full song is completely different than the US-spec E28 M5's S38b35. Makes the hairs on the back of your neck stand on end. Also I can routinely break the rear end loose from a stop light in my car with 275 width rear tires (in the dry). That was in 40 degree weather though on ZR tires .... shrug. Still the amount of power the car has demands attention from the driver.
Adam Wilson
www.e12m535i.com
I'm running a chip in mine that is supposed to do a decent performance bump. I have not dynoed my car to verify, but other S38b38 owners with the chip are doing between 300-310 at the rear wheels. With some uprated cams, a more agressive chip (and strict adherance to higher octane fuel) and a few other tweaks, I think you could see 400 horsepower out of an S38b38. I would guess that is about the limit for street reliability and natural aspiration. That's not based on expert opinion, just from what I've read and seen on the E34 M5 list.
I don't know why, but the howl/shriek of the S38b36/S38b38 motors at full song is completely different than the US-spec E28 M5's S38b35. Makes the hairs on the back of your neck stand on end. Also I can routinely break the rear end loose from a stop light in my car with 275 width rear tires (in the dry). That was in 40 degree weather though on ZR tires .... shrug. Still the amount of power the car has demands attention from the driver.
Adam Wilson
www.e12m535i.com
Just Curious About the Max Power output....
Max Power?
How much money do you have???
The NA S38 is probably good for 500>550HP; but not for long... and not for cheap...
When you're done, you've got an engine will be so peaky that all the fun will be out of it. The engine will be tuned for such a narrow range with such high revs (increasing RPM effectively increases cubic inches) that it won't be the car you know and love anymore. Much better get a turbo and larger engine - there is no substitute for cubic inches, but large sums of cash seem to be almost indistinguishable...
How much money do you have???
The NA S38 is probably good for 500>550HP; but not for long... and not for cheap...
When you're done, you've got an engine will be so peaky that all the fun will be out of it. The engine will be tuned for such a narrow range with such high revs (increasing RPM effectively increases cubic inches) that it won't be the car you know and love anymore. Much better get a turbo and larger engine - there is no substitute for cubic inches, but large sums of cash seem to be almost indistinguishable...