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Thread: Mpfi intake swap vortec 5.7

  1. #21
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    Slowly but surely about the time i get it sorted ill tear it down for a cam swap. I keep meaning to post a log and tune. Unfortunately most my posts are coming from phone right now.

  2. #22
    Trial and error.
    2001 Jimmy ,L31 with marine intake,CPC conversion,Nv3500 5 speed,SAS,Dana 44's front and rear,4.30 gears..

  3. #23
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    well iv'e got the truck tuned for the most part. probably could touch up some of the higher load low rpm stuff. but i'm satisfied for the most part. i picked up some of that torque i thought was gone forever after i got it mostly dialed in. i feel like i have solid gains from 2800-5000 rpm. with the stock cam it still runs out of wind quickly after 5000.

    intake swap MAFCL tune 6 fine tune adjustment tune.hpt

    mostly tuned intake swap log.hpl

    here is a tune and log im still having issues with lean tip in, rich off throttle. especially before complete warm up. it has an excessive lean tip in.

  4. #24
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    Quote Originally Posted by bronc3buster842001 View Post
    Im gona take mine to the drag strip to. LOL. We only have 1/8 mile track local. Figured Id go make a few passes for shits and giggles..

    I was going to run the Ram Jet 350 cam. Basically mimic the Ram Jet without the fancy intake. They made 350hp @5200 and 400ft/lb of torgue @3500. Should be more than enough in my blazer. A stock motor was plenty. But who wants stock. LOL

    Goal is to try to squeeze 350hp+ out of it with minor mods.
    Having run both the Ramjet cam and a Lunati version of the Hotcam in the same engine, pulling around the same 6,000 lb Express van, the HOTCAM hands down is better all around.

  5. #25
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    Wanted to update the thread. I finally solved my issue the fix was in transient fueling. I raised my impact factor gain table by more than 50% also I raised my fuel boiling time vs map vs airflow multiplier table by about the same. I'm still dialing it in, but have completely rid of my lean tip in and rich off throttle symptoms.

  6. #26
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    I've considered going to an aluminum efi intake on my 96 instead of dropping a small fortune on a marine intake, sounds like you got it figured out...thanks for the info

  7. #27
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    Hands down one of the best mods I have done to the truck. Now fiddling with eoit to try to improve some off idle torque and rid of my raw fuel smell.

  8. #28
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    Small update put the truck on the rollers yesterday. I was impressed with my torque for days. Over 300 lbft from 1900-3600. Was able to avg 311 lbft. Hp was satisfying also she put down 259.5hp at 4850. Avg hp came out to 205. This was done on a Mustang dyno and my intake temp's were above 110* the entire session. it was 80+ ambient temp's . Needless to say I'm happy with my single plane intake, (edelbrock 29135) full length headers with home built 3" ORY single exhaust numbers. Afr was probably a hair rich it was under 12.5 for all three runs.

    Now she is aching for that cam swap.

  9. #29
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    do you have the IAT in the intake manifold or an intake tube?

  10. #30
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    Its in the intake tube. Still running the stock throttle body and hat. Currently my intake piping setup is nothing more than an embarrassment. It's no good for warmer weather. The filter is located on top of the passenger valve cover. I'm 110% guilty of creating a hot air intake. Gonna fix that when I tear it down for the cam swap.

    Edit.

    These dyno pulls were just to get a baseline hp/tq avg after the intake manifold swap/hooker longtubes & home built full exhaust. Im trying to see how much I gain from the cam and ls6 spring install. Of coarse the 170,000 mile heads are coming off to be magna fluxed and shaved. Pulling the chambers down to 59-60cc whatever .026 straight mill gets me down to. That's if the stock ass cast iron vortec heads aren't cracked anywhere in or around the chambers.
    Last edited by Oleblu; 04-21-2017 at 01:58 PM.

  11. #31
    Feels like I'm late to the party!

    Glad to hear you got the lean tip in figured out. I had blamed it mostly on the LS9 injectors I was using, but obviously the intake was mostly to blame. I had the lean spike pretty well eliminated, but it's been awhile and I'm not sure what I had done exactly.

    I wouldn't be too sure about the nv3500 giving up on you anytime soon. I had 12-15psi through my 355 with that intake and a hotcam for awhile and never had any trans problems. Stock replacement clutch is happily hanging together also, and now has a NA 11:1 408 with L92 top end abusing it. Never slipped under load. Of course I never had a professional tune, so I'm sure there was some power left on the table with my setups.

    The way I understand most nv3500 failures are from slamming gears (as opposed to spirited shifting) not actually from too much torque. On performancetrucks there are several people that ran one behind a boosted 5.3 and turned in some pretty good track times.
    1999 s10 blazer trailblazer edition nv3500 swap
    2006 GMC ccsb 4x4 duramax/allison

  12. #32
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    Oh the party is just getting started. There will be updates soon, as the truck is pulled apart for a cam swap at the moment. I decided to go big or go home. Went with the comp cams 08-503-8. better known in the lt1 world as the cc503 cam. I figured the intake and cam combo will compliment each other well. I'll be taking the heads to the machine shop tomorrow. Hoping to have it running this weekend or next week sometime.

    There will be plenty of (spirited shifting) on this transmission for miles to come. Like stated above Im fully confident in the nv3500. The worst part for me is the random 3rd gear lockout when I start getting a little radical with my shifts. No doubt from my lack of accuracy while really trying to (bang) 1-3.
    Last edited by Oleblu; 05-11-2017 at 12:51 AM.

  13. #33
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    Quote Originally Posted by Oleblu View Post
    Small update put the truck on the rollers yesterday. I was impressed with my torque for days. Over 300 lbft from 1900-3600. Was able to avg 311 lbft. Hp was satisfying also she put down 259.5hp at 4850. Avg hp came out to 205. This was done on a Mustang dyno and my intake temp's were above 110* the entire session. it was 80+ ambient temp's . Needless to say I'm happy with my single plane intake, (edelbrock 29135) full length headers with home built 3" ORY single exhaust numbers. Afr was probably a hair rich it was under 12.5 for all three runs.

    Now she is aching for that cam swap.
    I just found a GM cam that I am about to put in the Express. I made a couple of errors and damaged a couple of LS7 lifters and the Lunati Hotcam in the Express. A combination of not enough preload and too little spring pressure caused valve float and eventually caused a couple of lifter rollers to start locking up, scoring a couple of cam lobes. I am going to use the GM 357 HP 350 HO cam this time around. 215/223 @ .050, .474/.474 lift with a 1.5 rocker. Going to run it with 1.6s and LS6 beehives.

  14. #34
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    Bummer on the lifters, what springs were you running with the lunati hotcam? That GM cam is going to be a great choice in my opinion. On the ls6 spring subject I just finished building my factory vortec heads tonight with the ls6 springs. Milled them down to 58cc. after checking my installed height with the 787 retainers i found them all to be within the area of 1.748-1.753, I also checked my retainer to seal clearance, with brand new stock replacement fel-pro seals my shortest measurement came out to .582 and most all others came up to .600, less .060 for comfort space my closest retainer to seal will be .522, And for the valve job I ended up doing it personally. i managed to get the seats and valve faces to clean up very nicely with nothing more than some metal grinding compound and a bit of finessing with a drill. sometimes a little lapping will go a long way. anyways the cam i chose is definitely more aggressive, the comp cams 08-503-8 is 224/230 @ .050, .503/.510 with 1.5 rockers. LSA is 112



    I should be installing the heads, intake/distributor and button up the wiring harness tomorrow. The cam went in today after work, I decided to install it straight up as opposed to the 2* advance i was contemplating. if i regret it ill tear the water pump and front cover off and degree it with some advance. my dynamic compression ratio is coming up to 8.14:1 this comes from a static ratio of 10.31:1 after milling the heads, and running fel pro 1094 .015 compressed head gaskets with the pistons averaging .026 in the hole. Probably pushing it a little for an iron head, but we will see how it goes.

    Opinions always welcome.

  15. #35
    I put the LS6 sprngs on my heads when i had them machined for the screw in studs. Overkill for a stock cam at the moment with 1.6 rockers and a motor that only spins 5200 RPM. But the springs were free and may do a cam later
    2001 Jimmy ,L31 with marine intake,CPC conversion,Nv3500 5 speed,SAS,Dana 44's front and rear,4.30 gears..

  16. #36
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    Maybe I'll regret it later but I'm pretty confident in the press in in rocker studs. While I had the heads off I drilled the pushrod holes to 1/2" for 1.6 rockers if I ever decide to do that. did you install the springs yourself? I noticed while Installing them they fit pretty snug to the pocket of the spring it seemed like the outer spring pocket and the spring were literally the same size within .002-.004 they went on though without any real concern from me. Plenty of paint on those springs I noticed. Other than the excessive paint on the spring I believe the fit was just right.

  17. #37
    No had the machine shop down the road do mine. ya mine were a snug fit on the pocket also,and they were used springs.
    2001 Jimmy ,L31 with marine intake,CPC conversion,Nv3500 5 speed,SAS,Dana 44's front and rear,4.30 gears..

  18. #38
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    Quote Originally Posted by Oleblu View Post
    Bummer on the lifters, what springs were you running with the lunati hotcam? That GM cam is going to be a great choice in my opinion. On the ls6 spring subject I just finished building my factory vortec heads tonight with the ls6 springs. Milled them down to 58cc. after checking my installed height with the 787 retainers i found them all to be within the area of 1.748-1.753, I also checked my retainer to seal clearance, with brand new stock replacement fel-pro seals my shortest measurement came out to .582 and most all others came up to .600, less .060 for comfort space my closest retainer to seal will be .522, And for the valve job I ended up doing it personally. i managed to get the seats and valve faces to clean up very nicely with nothing more than some metal grinding compound and a bit of finessing with a drill. sometimes a little lapping will go a long way. anyways the cam i chose is definitely more aggressive, the comp cams 08-503-8 is 224/230 @ .050, .503/.510 with 1.5 rockers. LSA is 112



    I should be installing the heads, intake/distributor and button up the wiring harness tomorrow. The cam went in today after work, I decided to install it straight up as opposed to the 2* advance i was contemplating. if i regret it ill tear the water pump and front cover off and degree it with some advance. my dynamic compression ratio is coming up to 8.14:1 this comes from a static ratio of 10.31:1 after milling the heads, and running fel pro 1094 .015 compressed head gaskets with the pistons averaging .026 in the hole. Probably pushing it a little for an iron head, but we will see how it goes.

    Opinions always welcome.
    In a lightweight truck should not be a problem to run a higher DCR.

    I was running a K-Motion the machinest that set the heads up originally said would work well. Checked them and they were not even 90# at 1.8" and way too close to coil bind for comfort with the .536" lift. Thats what I get for not researching.

    Did you re-use the factory locks or change them out?

    I think the cam should do very well with my gearing, transmission and 4.3 converter. Running a 4L80E with dual stator 4.3 B82 converter that stalls 2,400 rpm and 5.13 gears with 29" tall tires. Cruises right at 3,000 rpm @ 70. I pulled a 6,000 lbs travel trailer down the highway in OD with no problem with the Lunati Hotcam. The Lunati cam actually pulled it better than the GM '395 Marine cam. It is like dragging a 10' tall, 8' wide parachute.

  19. #39
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    I reused the stock locks. I figured no need for plus .050 locks I don't intend to ever go over .530 ish lift, the vortec heads probably wouldn't do well with anything more than that. The stock head flow numbers only show a 2cfm increase from .500 to .600 lift. I was figuring something like 105-109 lbs on the seat closed at 1.750 installed height. I was always curious about the 4.3 converter behind a 4l80 would like more input on this. I have a 4l80 ready to swap in should anything happen to the nv3500.

  20. #40
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    Quote Originally Posted by Oleblu View Post
    I reused the stock locks. I figured no need for plus .050 locks I don't intend to ever go over .530 ish lift, the vortec heads probably wouldn't do well with anything more than that. The stock head flow numbers only show a 2cfm increase from .500 to .600 lift. I was figuring something like 105-109 lbs on the seat closed at 1.750 installed height. I was always curious about the 4.3 converter behind a 4l80 would like more input on this. I have a 4l80 ready to swap in should anything happen to the nv3500.
    The B82 converter is nice. Actually pulled better from a stop than the 2,600 stall 10.5" pheonix converter I had after it and drove around with much less slippage.

    I actually tore into the 906s. Turns out it had stock GM Vortec springs and +0.050" locks. GM specs the Vortec springs at 80 lbs seat at 1.7" installed height. Mine were actually right at 1.8" If you reverse calculate the numbers means it had something like 55 lbs seat pressure and they are only 256 lb/inch. That is only 190 lb open and I was turning up to 6,200 rpm and probably floating springs the last 1,500 rpm. Also explains why they are so close to coil bind with .536" lift. They are solid at 1.200". No wonder they felt like slinkies and it floated the roller lifters and beat them and the cam up. I guess I will end up running those LS6 springs with the offset locks. Should be good for around 0.600" lift with the Comp 787 retainers. The stock locks and 787s are said to be good for 0.550".