Low boost

[pelky350]

sorry I basically high jacked th turbo talk thread with this been at it for a while today, basically only seeing ten max turbo stops climbing, smoke clears up. 90cc pump, stage 1 injectors, factory turbo with 60-1 mod and intercooler. So far not funding leaks on exhaust side or intake side. Fuel filter new, low miles pump/ turbo. 5 psi fuel pressure. And no black smoke at 10psi. Messed with throttle cable to make sure had full throttle and that checks out also. it sounds like the turbo is spooling pretty good. But I feel like it's maybe loosing some power because I can use full throttle and it just doesn't seem like it's going as good as it should be.

 

[Hydro-idi]

Then you probably aren’t getting the full output of that “so called” 90cc pump. Turn the pump up a flat or two and see how it performs. Everything you have mentioned tells me our engine can use more fuel.
Has your engine been timed??

 

[david85]

Everything you have mentioned tells me our engine can use more fuel.
Has your engine been timed??

That's my thinking too. If he was rolling coal, I'd be tempted to blame the turbo, but this seems like running out of fuel.

...I dunno...is the boost pressure line to the gauge leaking??

 

[Thewespaul]

You can test your boost gauge with shop air and a paint gun regulator.
I agree your pump is not putting out the advertised volume, not calling Justin a liar, just that he’s not telling the truth

Try thickening up the fuel and see if that affects your fuel output/boost

 

[austin92]

You must be registered for see images

Here’s the one I made to test oil pressure and boost gauges


Sent from my iPhone using Tapatalk

 

[pelky350]

My flow sheet says 104 cc at 1000 rpms. Yes I can cloud an entire block with black smoke till the turbo spools up though so it does happen but it clears up. Same pump and injectors ran 20 psi on my 088 ats setup previous to this though.

 

[Macrobb]

To be fair, I cleaned up a stock pump(cranked to max) with about 7 psi on the dyno...(at 2400+ rpm)
that should be around 90cc's.

And yes, any 90cc pump will feel like it needs more fuel at the top end...because the pump is having trouble pushing fuel high in the revs, due to the limited filling-time across the head-to-rotor ports.
Yes, lower in the revs it will push more fuel. That's why justin's "rd2-90" is rated as 90cc and not the 104 it makes at 1,000 rpm.

 

[sjwelds]

So if you made 20 psi before, and only 10 now, with the same pump and injectors, then you have a leak somewhere. Plain and simple.

 

[Macrobb]

So if you made 20 psi before, and only 10 now, with the same pump and injectors, then you have a leak somewhere. Plain and simple.

But... he also modified the turbo(different wheel? New bearings, right?) and added an intercooler(which will drop pressure, even if the "air value" of each PSI is higher).

 

[pelky350]

Unless my intake manifold gaskets blew out I'm not able to find where else leaking on both sides. I can take a video of my boost guage it goes up to About 5 psi instantly before 1500 rpms and then just drops off after and slowly climbs to 10 and just holds even with increasing rpms

 

[pelky350]

Also after regarding my timing back to the 5-6ish it was set to by the shop it smells like raw fuel and smokes at idle until warm. But it seems to run smoother and a little less clattery. But power didn't change

 

[pelky350]

But... he also modified the turbo(different wheel? New bearings, right?) and added an intercooler(which will drop pressure, even if the "air value" of each PSI is higher).

Went from 088 non gated turbo to factory with banks compressor housing and 60-1 mod with banks downpipe and now added intercooler. It was making 12 max now just ten after intercooler. So no effects from cooler besides 2 psi lost which should be expected anyway. No leaks on cold side either. And when engine cold I felt all around all seams of turbo system and cannot fine any leaks. I'm gonna try and wire shut the wastegate or just take it off and tighten it down the right way. Though it's not connected to boost maybe the lower spring tension is letting it leak?

 

[Macrobb]

I think that's reasonable. You are pushig plenty of air through that turbo(lbs/min), just not the pressure. If it cleans up, does it matter?
I've had a hard time getting over 15 out of my factory turbo, and now I only get 12 at WOT(though I have a small crossover leak) . And this is with a rd2-110, and a setup I *know* makes 250 rwhp(320 crank), because I've dyno'd it a couple of times.
Oh, and yes, it cleans up, even at 12 psi.
Note that with a wastegated Banks, the same setup
would push 22psi and overdrive the **** out of it(way into the 'surge band' according to a turbo map I found).

I'm not sure on specifics, but the 088 exhaust housing and wheel is smaller then the 'factory turbo' you upgraded to, right?

Also, I want to point out that when I got this S360 turbo with .83 exhaust housing, everyone said I should be making more boost(only made 10 at wot), that something was wrong etc... I finally just put a .63 exhaust housing on it and pushed 25+ wih a much moee responsive setup. My takeaway? IDIs don't perform the way "the numbers" say they should. Not sure why, maby due to the cam timing being designed to save every scrap of air sucked in for N/A use.

 

[Thewespaul]

But he’s not complaining about the numbers he’s saying he has a lack of power, and the numbers are just an extension of that.

If it were me I would find a stock pump, max the fuel screw and install it and see what changes.

 

[Macrobb]

If it were me I would find a stock pump, max the fuel screw and install it and see what changes.

That's a good idea.