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Twin Turbo 928 fixed and back out there terrorizing the streets!

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Old 08-24-2010 | 09:09 AM
  #286  
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You're a mad scientist. Some great fabrication and customization to create this monster!

Any chance you'll have the car running for the upcoming Boston Shark Party?

Just curious, how much fuel do you burn through? Must be significant if the original pickup wasn't doing the job.
Old 08-24-2010 | 09:25 AM
  #287  
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I'm totally guessing, but if you have low frequency noise, I think it may be coming from the car. I think maybe higher frequency vibrations are being transferred to the vehicle causing it to resonate at lower frequencies. Creating low frequency sound from smaller objects is difficult to do. Then again it depends on what you calling low frequency.
You might try to trap/isolate these vibrations with some rubber bushings in the mount. You might try some sound mat on the pump cover (the part you remove to gain access to the pump) and maybe inside the hatch above the pump. This stuff is a lot less than Dynomat and just as good: http://www.raamaudio.com/

What is the engine you have ready to install after (or if) the 87 fails?
Old 08-24-2010 | 10:05 AM
  #288  
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DUDE,

I'm sitting here laughing my a$$ off at your post.

Most of us are out here trying to keep our engines intact and running, with the fervent hope that we can get another 10k miles out of a 25 y/o car before having to pull the engine and replace/rebuild it.

You're up there thrashing the hell out of it and TRYING to blow it up and you can't do it!

Hysterical.

This is the thread of the year IMO.
Old 08-24-2010 | 10:09 AM
  #289  
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Originally Posted by Mike Frye
You're up there thrashing the hell out of it and TRYING to blow it up and you can't do it!
Nothing hysterical about it. This is what happens when you take your time to properly tune an engine.
Versus taking half-assed advice from people who don't have a clue or any real world experience.

Keep up the good work Tuomo.
Old 08-24-2010 | 10:15 AM
  #290  
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My 87 squirter block survived 13 psi for 2-3 years with 140k on the clock. Everyone that knows me knows that I run my car hard every time I take it out. Amazing engines.
Old 08-24-2010 | 11:16 AM
  #291  
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Originally Posted by ptuomov
Only a small help with the fuel pump noise. It's still way too loud, especially at idle. I was able to cut off some high-freqnecy noise but the lower frequency noise is still there.

Any ideas what to do?

My next planned step is to use a stethoscope to listen to all the parts around the fuel tank and try to find out the path of sound transmission. Beyond that, I am out of ideas.
Dynamat the fuel tank?
Old 08-24-2010 | 11:36 AM
  #292  
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I think I would run two 044 pumps in parallel with check valves. One giant pump is circulating way too much fuel 99% of the time. That large capacity is also what makes all the noise. If you had two, you could trigger the second to come on with a relay tied to intake pressure. Anything over a bar of pressure and you would be ok. I'm running one 044 in my Audi and you can hear it, but it's not objectionable.

Last edited by 123quattro; 08-24-2010 at 02:30 PM.
Old 08-24-2010 | 11:46 AM
  #293  
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i heard about your car from Carl in Needham but, seriously, wtf ? hope to see this beast sometime !




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Old 08-24-2010 | 11:56 AM
  #294  
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Tuomo - are you running the Fuelab on the high or normal setting? Remember that they are PWM speed controlled (internal) and also simply have a wiring setup for low or high. If you are running it on high, you are running too much through them for 100% duty cycle, heating the fuel, AND it would be quite loud.
Old 08-24-2010 | 12:05 PM
  #295  
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Old 08-24-2010 | 12:06 PM
  #296  
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IMO it is unlikely that you will blow this engine up unless it detonates (unlikely since it sounds like it was tuned properly) or it overheats. Now, if you run it on a dyno for 4 hours, it may do just that since the airflow even from one of those superfans is probably not enough to simulate real-world airflow conditions. You probably won't kill the transmission either since you are not racing and really heating up the transmission fluid either...

Dan
'91 928GT S/C 475hp/460lb.ft
Old 08-24-2010 | 12:12 PM
  #297  
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Which Fuelab pump are you running? They have a couple different sizes, so inquiring minds will want to know. When I was researching pumps, I called their offices in Illinois, and they had some very friendly product engineers. By memory, the last gent I spoke to over there was Brian Paitz, and after getting him on the phone, he was a wealth of information. I would give them a call, there is likely something that can be done with the PWM trigger. I would also ask if it is OK to dampen the pump with something like the visoelastic material you are using. These pumps need to shed heat, and while normally they do so internally, introducing heat to the fuel, these pumps may also require some degree of external cooling, sinking to the housing. I wouldnt want you to cook your pump prematurely (although I have been assured that the electronics in these pumps can be rebuilt at Fuelab with a very reasonably 2-3 day turnaround).

So, lets review a couple things:
A - what pump model?
B - are you currently using a PWM controller?
C - are you currently using the internal "resitive sensing" speed controller?
D - are you using isolated mounting points for the pump clamp studs/bolts?
E - What is the current injector size and duty cycle, so we can determine how much excess flow the pump is providing to see if PWM throttling is an option
Old 08-24-2010 | 01:10 PM
  #298  
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Originally Posted by hans14914
So, lets review a couple things:
A - what pump model?
B - are you currently using a PWM controller?
C - are you currently using the internal "resitive sensing" speed controller?
D - are you using isolated mounting points for the pump clamp studs/bolts?
E - What is the current injector size and duty cycle, so we can determine how much excess flow the pump is providing to see if PWM throttling is an option

A: 42401 (revision c, I think)

B: No. I hae one programmed and boxed, but haven't wired it up yet. Instead, I am running it at constant reduced speed.

C: I did not know that the pump had a "resistive sensing" controller built in. Therefore, I do not know whether exists and if it exists whether it is operating or not.

D: I am mounting the pump to the stock bracket that normally houses both the filter and the pump. The stock bracket's stock rubber mounts are there. The pickup side is a short rubber hose. The pressure side is a stainless hose, however enclosed in foam and rubber. The pressure side stainless hose connects to a hard line in the fenderwell.

C: Currently, I am burning about 70 gph at peak power, but I hope to get that number up. At low loads, about same as stock S4. The pump provides 170 gph at 100% setting, but I am running it at the low setting. I think the low setting pumps probably about 70% of the full setting, which would be about 120 gph.
Old 08-24-2010 | 01:19 PM
  #299  
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Originally Posted by Mike Simard
Do you have one of the counterfeit Chinese "Bosch 044" pumps? That would be any "Bosch 044" pump from Ebay or anywhere else that's not an actual Bosch reseller.
It's a Fuelab Prodigy 42401c.

It would have been much easier to go with the Bosch 044, but I am already too close to 044's capacity.
Old 08-24-2010 | 01:21 PM
  #300  
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Originally Posted by Marine Blue
You're a mad scientist. Some great fabrication and customization to create this monster!

Any chance you'll have the car running for the upcoming Boston Shark Party?

Just curious, how much fuel do you burn through? Must be significant if the original pickup wasn't doing the job.
"Mad scientist" is about right. John's the scientist and I am slightly mad! ;-)

I'll try to make it to the 9-11 party.

I am burning about 70 gph at peak power by my calculations. The pump is probably circulating about 120 gph as I've set it up now.


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