how to get more HP from Turbo 5.3
Nov 9, 2020 | 02:45 PM
#21
Thread Starter
Teching In
Joined: Oct 2014
Posts: 20
Likes: 6
I really doubt you have maxed out the 3.5" downpipe unless you mean fitting it in your truck. On an NA motor, a single 3.5" would start to be an exhaust restriction at your power level, but a turbo system can handle a small amount of backpressure post turbo without significant drop off's in power that NA motors experience. The 3" downpipes don't show significant restrictions until ~800HP (what I'm told). Plus if you have something like a VSRacing 7875, the turbo has to be a bigger limitation than the 3.5" downpipe, at least I would think so. What do you have after the 3.5" downpipe?
Nov 9, 2020 | 07:09 PM
#24
Interesting. Yep, that's exactly what I have. the mishimoto looks to be a drop in replacement, I guess I should measure the depth I have to make sure I can fit another inch. should be good.
Now I just need to mock up pressure sensors for intercooler and turbo pre and post and test. should be interesting. I have a WG in the bend just before the turbo flange, does it matter if I put the pressure sensor before or after the WG? Assume It's important to test pre and post turbine rather than just compare downpipe pressure to manifold boost pressure?
Now I just need to mock up pressure sensors for intercooler and turbo pre and post and test. should be interesting. I have a WG in the bend just before the turbo flange, does it matter if I put the pressure sensor before or after the WG? Assume It's important to test pre and post turbine rather than just compare downpipe pressure to manifold boost pressure?
Nov 10, 2020 | 06:45 PM
#25
TECH Junkie
Joined: Jan 2007
Posts: 3,309
Likes: 265
From: Arlington, TX
Most interesting thread here in a while imo. Love your ride I just love sleepers so dang much. Teddy Roosevelt's "Speak softly and carry a big stick; you will go far"...what I live by. A lot of good people here with a wealth of info. Glad you're here drhill.
Nov 10, 2020 | 10:45 PM
#28
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Teching In
Joined: Oct 2014
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Well, checked out the car today, I forgot I actually did buy and install the larger intercooler (31x12x4) so that's not it. I ran a compression check and all cylinders were between 180 and 190 - all good there. BUT - I did find one cylinder where the plug was a little loose and the plug wire was very loose and there was a log of white corrosion inside the boot and on the boot end of the plug. Thinking this may be my problem - if that connection was bad enough, it wouldn't fire across the electrode under load and that would kill a lot of power.
I'm hesitant to drill my turbo manifold for a pressure gauge if I don't have to....my research has indicated that many many people have made 150-200 more RWHP than I am with this exact turbo on similar LS engines. I'll get it on the dyno or to the track asap to check it out....it should be making more power given the combo....
Thank you everyone for all the input and help - you guys are a wealth of knowledge!
I'm hesitant to drill my turbo manifold for a pressure gauge if I don't have to....my research has indicated that many many people have made 150-200 more RWHP than I am with this exact turbo on similar LS engines. I'll get it on the dyno or to the track asap to check it out....it should be making more power given the combo....
Thank you everyone for all the input and help - you guys are a wealth of knowledge!
Nov 10, 2020 | 10:48 PM
#29
Nov 12, 2020 | 11:15 PM
#30
Thread Starter
Teching In
Joined: Oct 2014
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Likes: 6
Well, went to the dyno and found a missing 100 rwhp. Turns out that loose plug and boot was the culprit, it fired the cylinder under low load but not with high load/cylinder pressure. Ran out of fuel at about 685 rwhp at about 5900 rpm. has much more in it....thanks for the help guys!