68 "GTTO" 5.3l Twin Turbo Build with 58mm Garretts
#41
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Yeah....ha i've been working the bugs out and not posting. But i had a little run in with some excessive crank case pressure.(Poor PCV and Breather routing) I dont really know what i was thinking. But started blowing serious oil after a 6psi pull.. or the first pull of that length and amount.
That led me down a path of questioning my oil drains... wondering if the turbos were shot... ended up pulling them out.. .got some good USA made Dynamic kits for a really good price. Midwest Turbo connection- Super helpful!
Plumbed in a oil scavenge pump... which i soon realized made it worse... just due to placement. Anyway... all in all. I'm back to gravity ...got a good pcv and breather and its not leaking or blowing oil out the exhaust. My new (reman) Alternator off ebay... took a crap on last friday. So i ran to the used parts place... to try another one. Sure enough! so now i have a crappy Alt on the car. Oh well.. .run'r!
Very frustrating last month.
Currently building 9psi. As of monday... and still working things out with my boost reference regulator / second pump switch... and jetting on the carb... but its getting clooooser! Feels great now, cant wait to bump up that boost tonight! https://ls1tech.com/forums/images/sm...ch/gr_eek2.gif
Here is the engine compartment shot currently!
When this thing comes on it is VIOLENT! Felt 15psi on monday accidentally ... Good thing i got off it fast.. cause it was going lean. but man once it hits like 2psi on the gauge... it shoots up faster than you can ever imagine. lol
That led me down a path of questioning my oil drains... wondering if the turbos were shot... ended up pulling them out.. .got some good USA made Dynamic kits for a really good price. Midwest Turbo connection- Super helpful!
Plumbed in a oil scavenge pump... which i soon realized made it worse... just due to placement. Anyway... all in all. I'm back to gravity ...got a good pcv and breather and its not leaking or blowing oil out the exhaust. My new (reman) Alternator off ebay... took a crap on last friday. So i ran to the used parts place... to try another one. Sure enough! so now i have a crappy Alt on the car. Oh well.. .run'r!
Very frustrating last month.
Currently building 9psi. As of monday... and still working things out with my boost reference regulator / second pump switch... and jetting on the carb... but its getting clooooser! Feels great now, cant wait to bump up that boost tonight! https://ls1tech.com/forums/images/sm...ch/gr_eek2.gif
Here is the engine compartment shot currently!
When this thing comes on it is VIOLENT! Felt 15psi on monday accidentally ... Good thing i got off it fast.. cause it was going lean. but man once it hits like 2psi on the gauge... it shoots up faster than you can ever imagine. lol
#43
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Well its been a very long time since i've posted on here.
Currently i'm switching over to an EFI set up, i've been diving in to the Mega Squirt stuff more. Decided on building an MS2/Extra board, and will be figuring out some EFI related details in the coming weeks/months. I am working on building the MS2 Board :
I also have been digging into the various intakes, and injectors and wiring schemes for the LS engines. Will update when i actually start buying them. There is a ton of info and its been fun/scary reading up on it.
Last years findings as a "New to Turbo" Guy:
Carb issues- Too much fuel- Ran good for the most part, but Never got over 10-11psi, because i still had popping(super rich 9.8afr) at times when i would stomp on it... it would then clear out kind of and smooth out. I suspect my Mallory boost reference regulator wasn't working properly or accurate.
-Twin 58mm turbos are awesome.... and come on extremely fast and violent. You have time to check maybe a single gauge or think about checking one, but no sense in looking at the boost gauge. lol once it hits zero vacuum it hits 10psi before you can blink. I'm excited to get some more tuning done this year with the Tuner Studios /Mega Squirt setup and the electronic boost control.
-My Alternator mount was not sufficient- I had this idea to mount the alt High on the passenger side, (i see several other guys doing it as well). Spaced off of a bolt hole on the water pump. Then using an old style turn buckle to tighten up the belt. My main alternator bolt holding it to the water pump/pivit point. Broke 3-4 times throughout the summer. I re-worked the bracket twice, and still i would lose the belt, or break the bolt. Currently being addressed. My point is, if that is your plan prepare to come up with a better plan. I'll post my findings.
-Also figured out a few lessons in crank case pressure the week before our open track road course weekend...Scrambled for a week it sucked!!!!
I had oil leaking from my turbos, tried throwing a single scavenge pump between them to send oil back, still had issues. Pulled both turbos apart and rebuilt them, still had issues, re-addressed the crank case ventilation and that was it all along.
Currently i'm switching over to an EFI set up, i've been diving in to the Mega Squirt stuff more. Decided on building an MS2/Extra board, and will be figuring out some EFI related details in the coming weeks/months. I am working on building the MS2 Board :
I also have been digging into the various intakes, and injectors and wiring schemes for the LS engines. Will update when i actually start buying them. There is a ton of info and its been fun/scary reading up on it.
Last years findings as a "New to Turbo" Guy:
Carb issues- Too much fuel- Ran good for the most part, but Never got over 10-11psi, because i still had popping(super rich 9.8afr) at times when i would stomp on it... it would then clear out kind of and smooth out. I suspect my Mallory boost reference regulator wasn't working properly or accurate.
-Twin 58mm turbos are awesome.... and come on extremely fast and violent. You have time to check maybe a single gauge or think about checking one, but no sense in looking at the boost gauge. lol once it hits zero vacuum it hits 10psi before you can blink. I'm excited to get some more tuning done this year with the Tuner Studios /Mega Squirt setup and the electronic boost control.
-My Alternator mount was not sufficient- I had this idea to mount the alt High on the passenger side, (i see several other guys doing it as well). Spaced off of a bolt hole on the water pump. Then using an old style turn buckle to tighten up the belt. My main alternator bolt holding it to the water pump/pivit point. Broke 3-4 times throughout the summer. I re-worked the bracket twice, and still i would lose the belt, or break the bolt. Currently being addressed. My point is, if that is your plan prepare to come up with a better plan. I'll post my findings.
-Also figured out a few lessons in crank case pressure the week before our open track road course weekend...Scrambled for a week it sucked!!!!
I had oil leaking from my turbos, tried throwing a single scavenge pump between them to send oil back, still had issues. Pulled both turbos apart and rebuilt them, still had issues, re-addressed the crank case ventilation and that was it all along.
#45
TECH Enthusiast
Awesome build man!! Definitely sub'd!
I also have a Pontiac with a BBC and will be converting to LS/TT eventually. Mine is a 69' Grand Prix, factory 4 spd. Currently a 461" BBC..
Can't wait to do a LS/TT setup with a 6spd.
I also have a Pontiac with a BBC and will be converting to LS/TT eventually. Mine is a 69' Grand Prix, factory 4 spd. Currently a 461" BBC..
Can't wait to do a LS/TT setup with a 6spd.
#46
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#47
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Oh right on! Gonna be sick ! Just the other day I was looking at those TKO 5 speeds. It would be handy on the road course!
#49
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Probably gonna do a 5.3, Holley high ram, and some twin 58s similar to yours. I'm not building this one into a 1/4 mile car... Just going to put a resto-mod spin on it with some power and still have decent economy and all creature comforts and make a nice cruiser that still has some *****..
It's been in our family for 30 years so I'm ready to change it up a bit..
Were you able to use the stock pontiac gauges or you do a f body cluster or something? I would really like to keep all of the stock gauges working other then the tach.. I don't want a bunch of gauges and crap in this one.
I'm gonna follow along as you go fuelie on yours and see how it turns out. Gonna mirror my turbo layout like yours... Yours looks awesome.
#50
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Yeah I'm looking forward to it.. It's definitely an odd ball... A big *** car with a stick tranny...
Probably gonna do a 5.3, Holley high ram, and some twin 58s similar to yours. I'm not building this one into a 1/4 mile car... Just going to put a resto-mod spin on it with some power and still have decent economy and all creature comforts and make a nice cruiser that still has some *****..
It's been in our family for 30 years so I'm ready to change it up a bit..
Were you able to use the stock pontiac gauges or you do a f body cluster or something? I would really like to keep all of the stock gauges working other then the tach.. I don't want a bunch of gauges and crap in this one.
I'm gonna follow along as you go fuelie on yours and see how it turns out. Gonna mirror my turbo layout like yours... Yours looks awesome.
I did use the stock cluster but I did add the a-pillar gauge mount (that I had to make...they don't make one for the A-body :/ ..) then deleted the radio and have 3 gauges there. I did manage to fit a tach in the factory cluster. Not as easy to see as I'd like but it's somewhat hidden.
#51
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Last drive of the year!!
Forgot to post this video up! Last drive of the year, the day i finally got back from being on Tour it was November 5th i think!
Was messing with the video editing some. Nothing to crazy just some 10psi pulls. Still was so good driving that again after 7 weeks of being gone!
Was messing with the video editing some. Nothing to crazy just some 10psi pulls. Still was so good driving that again after 7 weeks of being gone!
#53
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It's purpose was just a temporary paint. I have the car jammed and engine bay painted a dark charcoal metallic. But that may be revisited. I Just wanted to get it on the road. It's made by Hot Rod Flatz! One stage flat paint.
#54
If that is a original stick Pontiac Gran Prix those cares are rare. 500 or less were built..Dont hack that one if its original. Sorry for the rant but that poncho is nice. Had a pretty fast one back in the day..faster than most GTO's at the time. I think it was a factory freak!
#56
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Forgot to post this video up! Last drive of the year, the day i finally got back from being on Tour it was November 5th i think!
Was messing with the video editing some. Nothing to crazy just some 10psi pulls. Still was so good driving that again after 7 weeks of being gone!
http://www.youtube.com/watch?v=pcxycvdKisM
Was messing with the video editing some. Nothing to crazy just some 10psi pulls. Still was so good driving that again after 7 weeks of being gone!
http://www.youtube.com/watch?v=pcxycvdKisM
#57
TECH Enthusiast
If that is a original stick Pontiac Gran Prix those cares are rare. 500 or less were built..Dont hack that one if its original. Sorry for the rant but that poncho is nice. Had a pretty fast one back in the day..faster than most GTO's at the time. I think it was a factory freak!
Yep GPs are odd ball cars.. You either love em or hate em...
#58
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Thanks man! Yeah I figured I could get away with just coming straight off the turbo....and I did.. but it is loud lol. Not so bad when I throw it in overdrive/lockup but otherwise when you are on your converter driving around town it's loud. Lol. I'm looking at some low profile 3" mufflers I found I would like to do something to quiet it a bit. But yes they come straight back and dump right before the Axle. The original plan was to turn them out a bit.
#59
Thanks man! Yeah I figured I could get away with just coming straight off the turbo....and I did.. but it is loud lol. Not so bad when I throw it in overdrive/lockup but otherwise when you are on your converter driving around town it's loud. Lol. I'm looking at some low profile 3" mufflers I found I would like to do something to quiet it a bit. But yes they come straight back and dump right before the Axle. The original plan was to turn them out a bit.