My draw through turbo

[advinnie]

I'm back first off yes I'm using a boost sensitive fuel pressure regulator that's set at 3 psi at idle and rises 1 psi for 1 psi of boost (if that makes sense)
One thing I have noticed is that my fuel pump can only produces 14psi max but it is flowing 110 gallons an hour so still more than enough fuel for a draw through set up.
Any way some news on my max boost runs I hit 16psi boost in 3rd and that's all I can get BUT fourth gear is another story. Doing 50mph in fourth then floored it hit 90mph very fast, looked at the boost gauge and saw 21psi, I didn't believe the gauge so checked my laptop and that recorded a high of 22psi . I'm not going to do that again I was shitting myself big time but it was fun. Going to refitt my 14psi wastewater spring and play it safe.
All I can say is F#@k this little 1600 is fast at 22psi of boost. I wish I timed the 50 to 90mph acceleration run
And with the 160 mains I had a A/F ratio reading of 12.5:1 but trying to cruse between 60-70mph was hard she felt fat and heavy and very unhappy.
So much for just wanting a few psi boosted bug witch was my original plan

[advinnie]

By the way can soneone explain why I can only get 16psi boost in 3rd but in fourth I can get another 6 psi?

[buguy]

Sounds awesome! Your lucky! Mine doesn't feel like it would even come close to even being able to produce that much boost. My waste gate stops me at 8-9 psi.

[advinnie]

Can't you just change your wastewater actuator spring like I can? Believe me I was happy with just running 8psi but the difference between 8and 14 psi boost is just undesirable BUT I have to say that to run 14psi my motor does run rich at constant throttle she ran best when the fuel ratio was correct for 10 psi and I may even dropped it back to that figure but first I'm going to spend a few weeks set up for 14 psi and see how things go.

[buguy]

Oh sure I could crank it up, but I don't know that it would ever make the boost numbers you are seeing... I really don't know. Once I'm 100% happy with the tune I will be turning up the boost. I'm at about 7.5:1 compression so I should be good to go to 12-16 psi safely.

[advinnie]

What size turbo you running?
In also running 7.5:1 compression ratio.
I've now got it all set up to run 14psi boost. Idle jets had to be dropped from a pair of 55 F9's to a pair of .50 F8's and mains have been dropped from the 1.60's to 1.52's. had to call it a night cause I had a little scare, went out for a drive to make sure the new jetting is ok for 14psi and started to smell gearbox oil, pulled over and it was dripping fast all over the roaf. Sod it I thought I've broken the stock box, so drove her home nice and easy jacked her up only to find out its the dam axle boot that's split thank god.

[buguy]

I'm using a tiny Subaru turbo.
Glad to hear you didn't break it! That would be no fun!

[advinnie]

New axle boots on order
When does your size turbo start to build boost?
Mine starts building boost around 2500 rpm and am at 10 psi by 3800 rpm

[Chip Birks]

Gosh, you guys and your tiny turbos! I don't think mine starts spinning until 4k. Makes decent boost by 4500, but not great.

[buguy]

I'm not real sure where mine starts. I haven't spent much time in it and not easy to watch the tach and the boost gauge. They aren't near each other. I think I have a couple leaks in my header. It's a hack job header I made out of an old rusty header nearly 10 years ago. Here it is when I had the engine out last time. This is with the old turbo.

[advinnie]

Your header is the same as mine and it works great.
My turbo is not that small it's an aireserch (T3) with a .36 hot side and a .42 cold

[buguy]

Mine has some areas that are real sharp bends and places I had to heat it and twist it to get it to line up. I've also noticed a couple spots that have black spots that are where exhaust is coming out. Must be on the welds that I ground down and have pin holes. It works ok but could be better I'm sure. Also I recently I put new trans mounts on and it hits the body now because it lifted the engine since the old mounts were so bad. The T3 I had on it was a 42/.48 and the Subaru turbo is quite a bit smaller. I don't know the AR numbers on it.

[advinnie]

My mates running a tiny GT15 turbo on his 1600 and that thing is building boost just of off idle and it's a blast to drive round town and the back roads.

[buguy]

I've thought about getting something similar to that myself. Most of my driving is in town stoplight to stoplight. 50mph zones or less.

[advinnie]

In that case yes get the GT15 turbo from a 1.6 diesel vauxhall zafira and he's blowing through a Renault 5 GT carb witch I believe is called a solex 32 DIS