My draw through turbo
-
advinnie
- Posts: 984
- Joined: Mon Jun 10, 2013 4:54 am
Re: My draw through turbo
Most of the books I've read say that the return line needs to be bigger than the feed so it's less restrictive and doesn't cause a pressure build up on the return port of the regulator
-
advinnie
- Posts: 984
- Joined: Mon Jun 10, 2013 4:54 am
Re: My draw through turbo
Hold on you have me thinking now, I'm going to have to go and check. Will be back in a bit
-
andy198712
- Posts: 2433
- Joined: Wed Apr 13, 2011 1:01 pm
Re: My draw through turbo
Correct in hydraulic systems the return line needs to be bigger then the feed, if it was smaller and your running the system to it’s limits, then in theory the feed line can flow more than the return line and it will cause a back up of pressure... potentially
-
advinnie
- Posts: 984
- Joined: Mon Jun 10, 2013 4:54 am
Re: My draw through turbo
Totally forgot to look at the fuel line sizes but I have solved the fuel bowl running lean. There is/was a werid slime in the fuel filter between the fuel tank and fuel pump. About to check the fuel lines to see if its got passed the filter. It is also in the fuel tank which my friend has kindly taken to his work place to blast it and clean it out
- rubenski
- Posts: 2038
- Joined: Mon Jun 30, 2014 3:28 am
Re: My draw through turbo
Gettin' there, problem after problem! Keep it up!
Better to be blown than to suck!
-
ct937
- Posts: 28
- Joined: Thu Feb 07, 2019 10:00 am
Re: My draw through turbo
Just wanted to chime in about the Holley Blue fuel pump. It’s max PSI is 14 but it does not run a constant 14 PSI. That pressure will drop significantly as it’s asked to deliver more fuel. Not to mention that the Blue pump does high volume better than it does high pressure. It’d be perfect for an NA V8.
I’m not sure the Blue would be good for more than 5-6 lbs of boost. It sounds like you may have already experienced this first hand. Enlarging the return line would only make the issue worse as seen with your sequential 100 mph pulls. The smaller return line would have been adding a restriction and allowing the pump to hold a higher fuel pressure for longer.
If cleaning your lines and tank does not solve the fuel delivery issue I would add a fuel pressure gauge and moniter fuel pressure to see if it stays 3 PSI ahead of your boost level. There may be a certain point where it can’t push high enough pressure even if it can flow plenty of fuel. I had a Holley Blue available for my build but opted for a Walbro GSL392 because it supports much higher fuel pressure even though it flows less total volume.
I’m not sure the Blue would be good for more than 5-6 lbs of boost. It sounds like you may have already experienced this first hand. Enlarging the return line would only make the issue worse as seen with your sequential 100 mph pulls. The smaller return line would have been adding a restriction and allowing the pump to hold a higher fuel pressure for longer.
If cleaning your lines and tank does not solve the fuel delivery issue I would add a fuel pressure gauge and moniter fuel pressure to see if it stays 3 PSI ahead of your boost level. There may be a certain point where it can’t push high enough pressure even if it can flow plenty of fuel. I had a Holley Blue available for my build but opted for a Walbro GSL392 because it supports much higher fuel pressure even though it flows less total volume.
-
madmike
- Posts: 3146
- Joined: Mon Jul 24, 2006 3:11 pm
Re: My draw through turbo
I've ran up 18 Lbs of Boost with a Blue pump and could of run more if I had better fuel
2276cc
- buguy
- Posts: 6209
- Joined: Wed Jan 26, 2005 8:53 pm
Re: My draw through turbo
But you also have huge fuel bowels in your carb. That helps alot!
-
advinnie
- Posts: 984
- Joined: Mon Jun 10, 2013 4:54 am
Re: My draw through turbo
Well lads looks like this is the end of the line for me. The bug has won another competition on Facebook and today I had a visitor come round my house and wanted a drive so I took him out and he loved it and asked if I would ever sell it. I said yes if the price was right. To that he offered £10,000 
- rubenski
- Posts: 2038
- Joined: Mon Jun 30, 2014 3:28 am
Re: My draw through turbo
So it's sold?
Now an ecu upgrade in the other one?
Now an ecu upgrade in the other one?
Better to be blown than to suck!
-
advinnie
- Posts: 984
- Joined: Mon Jun 10, 2013 4:54 am
Re: My draw through turbo
Yes it's sold, the buyer is picking it up on Sunday. For the first time in 15 years i will be without a bug 

-
advinnie
- Posts: 984
- Joined: Mon Jun 10, 2013 4:54 am
Re: My draw through turbo
But I have seen this
https://www.ebay.co.uk/itm/VW-CLASSIC-B ... %7Ciid%3A1
https://www.ebay.co.uk/itm/VW-CLASSIC-B ... %7Ciid%3A1
- buguy
- Posts: 6209
- Joined: Wed Jan 26, 2005 8:53 pm
Re: My draw through turbo
Bummer. I had that happen on my other one. I did all the resto at work and the day before I was going to take it home someone stopped by and made me an offer I couldn't turn down.
- V8Nate
- Posts: 849
- Joined: Mon Sep 03, 2018 12:34 pm
Re: My draw through turbo
Cant keep them all, nice 70 though:)