5.3 s475 slow spool
Thread Starter
Teching In
Joined: Aug 2021
Posts: 8
Likes: 3
5.3 s475 slow spool Hey guys new here been dealing with my car for last few years with different setups. Car is a 85 iroc 5.3 aluminum block, s475, Bosch 1000, dual fuel pumps, terminator x, th400 3500stall, Chinese 44mm wastegate, sloppy stage 2 cam and flow sheet metal intake. When out cruising or on dyno car is really sluggish to come
up on boost lazy from that 1200-3200 range. Once it lights it’s makes decent power . But is extremely laggy any ideas on what could be causing this?. Second setup and still same thing .
up on boost lazy from that 1200-3200 range. Once it lights it’s makes decent power . But is extremely laggy any ideas on what could be causing this?. Second setup and still same thing .
throw alot more timing at it and see if it peps up. No sustained WOT runs here - just testing your part throttle response. Intake isnt helping. Make sure engine is mechanically sound, wastegate is holding. After that maybe the converter.
Are you running any kind of boost controller? If it's not too much trouble. can you take your wastegate off and bench test it to see when the gate starts to crack open the valve and at what PSI? I'm just wondering if backpressure is causing the WG to open prematurely. What PSI spring is in your WG? Have you checked everywhere (hotside and coldside) for leaks?
Thread Starter
Teching In
Joined: Aug 2021
Posts: 8
Likes: 3
Engine is now apart right now was mechanically sound. Fresh rebuild , 150-160 across board. Has flow intake 102 tb deff not a restriction. Timing has been bumped but isn’t helping, gate holds 18 psi and doesn’t crack or leak. Exhaust is 2.5 cross overs to turbo then 4 inch dump. Car makes killer power and wants way more timing up top but was limited to pump gas 91. Makes 620on 17 psi. No leaks on smoke test.
On The Tree
Joined: Nov 2020
Posts: 131
Likes: 9
I run almost the exact same setup,,same cam and 5.3 etc.I run the airwerks s475 and it spools very quickly for me.When I first put mine together it wouldnt spool very well because of the converter.I changed converters and its night and day now.I ran bbc before the ls and they didnt care would spool anything.The ls engines seem alot more finnicky and need matched up alot better
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Thread Starter
Teching In
Joined: Aug 2021
Posts: 8
Likes: 3
I run almost the exact same setup,,same cam and 5.3 etc.I run the airwerks s475 and it spools very quickly for me.When I first put mine together it wouldnt spool very well because of the converter.I changed converters and its night and day now.I ran bbc before the ls and they didnt care would spool anything.The ls engines seem alot more finnicky and need matched up alot better
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Hey guys new here been dealing with my car for last few years with different setups. Car is a 85 iroc 5.3 aluminum block, s475, Bosch 1000, dual fuel pumps, terminator x, th400 3500stall, Chinese 44mm wastegate, sloppy stage 2 cam and flow sheet metal intake. When out cruising or on dyno car is really sluggish to come
up on boost lazy from that 1200-3200 range. Once it lights it’s makes decent power . But is extremely laggy any ideas on what could be causing this?. Second setup and still same thing .
up on boost lazy from that 1200-3200 range. Once it lights it’s makes decent power . But is extremely laggy any ideas on what could be causing this?. Second setup and still same thing .
TECH Enthusiast
Joined: Mar 2013
Posts: 503
Likes: 38
Reminds me of the time I first drove my uncle's high stall Firebird as a kid. There was ice on the road and I had never driven a car with a tach before. I mistook the tach for the speedometer and since I heard the engine revving up I thought it was slipping on the ice. You are not going to build much boost at part throttle and as someone has said, why would you want to. As far as feeling "laggy" below the stall speed? Who could have guessed that was going to happen or better yet what it even means?
On The Tree
Joined: Nov 2020
Posts: 131
Likes: 9
I run almost the exact same setup,,same cam and 5.3 etc.I run the airwerks s475 and it spools very quickly for me.When I first put mine together it wouldnt spool very well because of the converter.I changed converters and its night and day now.I ran bbc before the ls and they didnt care would spool anything.The ls engines seem alot more finnicky and need matched up alot better
Thread Starter
Teching In
Joined: Aug 2021
Posts: 8
Likes: 3
just took my convertor out to trans shop b&m 20482. Think something has failed in it will be getting some
info when they cut it open today. Doesn’t feel like it’s hooking up , I have a video of the dyno pulls but can figure how to post it. So everyone can see what my issue is
info when they cut it open today. Doesn’t feel like it’s hooking up , I have a video of the dyno pulls but can figure how to post it. So everyone can see what my issue is
just took my convertor out to trans shop b&m 20482. Think something has failed in it will be getting some
info when they cut it open today. Doesn’t feel like it’s hooking up , I have a video of the dyno pulls but can figure how to post it. So everyone can see what my issue is
info when they cut it open today. Doesn’t feel like it’s hooking up , I have a video of the dyno pulls but can figure how to post it. So everyone can see what my issue is
For an auto turbo car the converter much like the cam is absolutely critical.
I'm running the Circle D LS Pro converter in mine and they've been great to work with, even pulled it back out to have it tweaked since it wasn't locking up on the top end (most likely because of the trans).