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Discussion Starter #1
Back in December, we dyno'd at 331 rwhp and 375 rwtq. We also identified problems with the air/fuel ratio. After having the injectors rebuilt, replacing the plugs, air filter, and fuel pressure regulator (as well as a bunch of other unrelated stuff), today it dyno'd at 369 rwhp and 401 lbft rwtq. I was also able to identify a bad AFM, as well as a bad spare. So, no revving over 4500rpm until it's replaced. :sad2: I gotta say, after 21 years and 107k miles on a stock motor, you just can't ask for better... :1:
 

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Back in December, we dyno'd at 331 rwhp and 375 rwtq. We also identified problems with the air/fuel ratio. After having the injectors rebuilt, replacing the plugs, air filter, and fuel pressure regulator (as well as a bunch of other unrelated stuff), today it dyno'd at 369 rwhp and 401 lbft rwtq. I was also able to identify a bad AFM, as well as a bad spare. So, no revving over 4500rpm until it's replaced. :sad2: I gotta say, after 21 years and 107k miles on a stock motor, you just can't ask for better... :1:

That is alot hmmm

It means you have almost 400 hp in the engine :eek:oohhh:

Your engine can not be original then .......... I know that Alpina engines gives more than they say but 70 hp hmmm

How much turbopressure are you running at ? ( original is 0,85-0,9)
 

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That is alot hmmm

It means you have almost 400 hp in the engine :eek:oohhh:

Your engine can not be original then .......... I know that Alpina engines gives more than they say but 70 hp hmmm

How much turbopressure are you running at ? ( original is 0,85-0,9)

know-it-all mode on:


it must be less than 20 psi !
:cool2: for sure :cool2:

know-it-all mode off !
 

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Know-it-all confirmation: Alex is correct! Tops we saw was 16.6 psi, with a load on. But that was only running it to just under 5000 rpm. When I get a new AFM, we'll run it up to the redline. BTW, Alex, what mods have you made to run at 20? To my knowledge, there are no mods to my car...
 

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Know-it-all confirmation: Alex is correct! Tops we saw was 16.6 psi, with a load on. But that was only running it to just under 5000 rpm. When I get a new AFM, we'll run it up to the redline. BTW, Alex, what mods have you made to run at 20? To my knowledge, there are no mods to my car...
Everything was done by member alpinafahrer and one of his buddies:
The B7 has Je Pistons, block was o-ringed and it´s runnning on the 2.16mm 745i HG, the k27 had to be modified extensively to accept the 60 trim compressor wheel,he did something to boost control / ecu which allows me to open up the boost w/o end :nono: but it runs a little lean on top.it has a different wastegate spring from what i know but i didn´t have a look yet.the engine had several HG failures during the years but the rest is perfect :blabla: it isn´t recommend for true enthusiast as it wears out the nice engine. but i was done before so i let this as it is.
 

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Discussion Starter #8
Everything was done by member alpinafahrer and one of his buddies:
The B7 has Je Pistons, block was o-ringed and it´s runnning on the 2.16mm 745i HG, the k27 had to be modified extensively to accept the 60 trim compressor wheel,he did something to boost control / ecu which allows me to open up the boost w/o end :nono: but it runs a little lean on top.it has a different wastegate spring from what i know but i didn´t have a look yet.the engine had several HG failures during the years but the rest is perfect :blabla: it isn´t recommend for true enthusiast as it wears out the nice engine. but i was done before so i let this as it is.
Sounds like a rising rate fuel regulator might help your top end leaning issue. You should check out Bell Engineering (BEGi).
 

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JT, so that is the answer finally to the many queries, from both this and the last dyno run, on how you're getting such high hp readings on this car, no?

Correct me if I'm wrong, but 16.6psi is ~1.14bar, vs the Alpina spec and according hp ratings for about 0.9 bar.

The followup would be why/how are you getting 1.14bar readings with the stock Alpina wastegate? (Or is this the magic that took you from Turbo/1 to Turbo/2? ;))

Actually, mightn't that be having some affect on your leaning out up high as well?
 

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Sounds like a rising rate fuel regulator might help your top end leaning issue. You should check out Bell Engineering (BEGi).
i got one from m5killer and i also have a upgrade fuel rail but the rail doesn´t fit properly at the moment.

i dídn´t install the FPR yet.
@m5 killer :but but i promise to do it soon :1:
 

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Discussion Starter #11 (Edited)
JT, so that is the answer finally to the many queries, from both this and the last dyno run, on how you're getting such high hp readings on this car, no?

Correct me if I'm wrong, but 16.6psi is ~1.14bar, vs the Alpina spec and according hp ratings for about 0.9 bar.

The followup would be why/how are you getting 1.14bar readings with the stock Alpina wastegate? (Or is this the magic that took you from Turbo/1 to Turbo/2? ;))

Actually, mightn't that be having some affect on your leaning out up high as well?
Nah, Turbo/2 has a 280 degree cam, vs. 262 for Turbo/1 (decided to change it in my profile, as I finally uncovered the "B7/2" stamping on the engine block, above the starter!). But this wouldn't affect the charge air pressure. AFAIK, the installed gate is factory (it sure looks it - also, there are no markings on the diaphragm case that would indicate a spring change). Logic assumes as it ages, boost pressure would decrease, rather than increase. The only other possibility is the turbo impeller pitch. The turbo case looks sufficiently old enough to be original. It has original markings (for Alpina specs). The cold side impeller blades do look pretty clean for a car of its age, so perhaps the center section was changed at some point in its life. Unfortunately, much of the history of the car is a mystery to me, so it's impossible to say one way or another. I can say that the fuel and ignition systems are stock. Also, understand that the reading was taken with a load on the dynomometer, and full boost normally wouldn't be achieved on a dyno that has no load (at least that's my understanding). Perhaps that has some bearing on the boost (or more correctly, overboost) reading... ;-)

BTW, the leaning was corrected with the spare AFM - unfortunately it had other, more serious issues, and I reinstalled the original. I still get the leaning at the top end, but it looks like the injector rebuild solved the high ratio on the lower end. As soon as I get a replacement AFM, we'll re-run the dyno & see what happens. If it's still lean, I have a rising rate regulator to install...
 

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Discussion Starter #12
i got one from m5killer and i also have a upgrade fuel rail but the rail doesn´t fit properly at the moment.

i dídn´t install the FPR yet.
@m5 killer :but but i promise to do it soon :1:
"Upgrade fuel rail?" Can you give me details?
 

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Discussion Starter #15
JT, so that is the answer finally to the many queries, from both this and the last dyno run, on how you're getting such high hp readings on this car, no?

Correct me if I'm wrong, but 16.6psi is ~1.14bar, vs the Alpina spec and according hp ratings for about 0.9 bar.

The followup would be why/how are you getting 1.14bar readings with the stock Alpina wastegate? (Or is this the magic that took you from Turbo/1 to Turbo/2? ;))

Actually, mightn't that be having some affect on your leaning out up high as well?
You know, Mike, I'm slow but I eventually get there. :hihihi: Was concentrating on another related subject today and it hit me. A couple of years back, my Alpina muffler finally bit the dust. Since the back section is NLA from Alpina, I replaced it with a UUC M5/6 stainless setup. The free flow may account for the extra boost and HP....
 
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