5.3 blow through carb setup in my 56 chevy
03-15-2017, 08:24 PM
#1
5.3 blow through carb setup in my 56 chevy Hey guys I been searching and reading a ton of info on here first off thank you guys for having such a great group of guys willing to help. I have already learned a ton of info from you guys. So here is my setup I have a bone stock 5.3 with a on3 76mm turbo on it. I know it's not the perfect setup but I wasntes to get something together for this spring my old motor was a 327 and the car ran 13 flat in quarter mile. So the other day I finally got the car up and running . I modified a 850 double pumper to blow through by reading hangar 18 instructions. The timing is one of my biggest things I need to figure out with the msd. What is a good start for timing? What kind of timing curve? Also how much are you guys letting the map sensor retard the timing as the boost starts coming in? I am going to try and run this setup at 10lbs boost. I have a 3500 stall converter and a th400 trans. Right now the car has 4.56 gears and I know that will need to be changed. What gears do you guys reccomend? I was thinking about trying 3.50 gears. Thanks for al you guys help!
03-16-2017, 12:25 PM
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Are you building for a street/strip application or a daily or just for racing? going from 4:56's to 3:50's is a pretty drastic change. maybe there's a flaw in my logic, but I personally would recommend going with 3:73's or maybe 4:11's depending on what you're looking for in your end goal. Keep in mind as well, you did say you're trying to run 10lbs of boost on a stock 5.3... I would most certainly consider changing the cam, at the very least, to something more aggressive with less overlap than the stock cam.
03-16-2017, 03:00 PM
#4
It's for 1/4 drag racing. The 456s were 6000 rpm at 100mph out the other end of the strip. I do have a set of 390 gears I could try. They are sitting here but I heard you need a hard load on the turbo to make the turbo work right. I thought about cams but was reading suoerchevy saying with a blow through setup with a bone stock 5.3 at 10lbs they got 527hp. After they changed cam they got 611 out of it. So I figured before since my old powertrain made the car run 13 flat being the motor was like 350 hp that this new setup being 500 hp should run pretty good.
03-16-2017, 04:03 PM
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no doubt it will run better. I would throw the 3:90's in the diff and see what you get on a "test and tune" basis. Yes, turbos yield better performance under a load but I don't doubt that 3:90 gears would give you a better ratio and some engine load all the same. you want to get to your top speed quickly VS having I higher top speed 6 miles later. (sure 3:50's will get you a higher top speed, but you will have a slower 1/4 time)
03-16-2017, 08:54 PM
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What fuel are you running? Interooler? Meth? I am in the process of gathering my parts as I am moving from nitrous to turbo. There are a lot of good threads on timing with the MSD boxes out there. I have been hounding Google lately haha
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03-17-2017, 01:16 PM
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Heres some info, hope this helps.....
Timing: Run NA timing (30/32/34 just depends what the motor likes) up until 15psia on the map table (atmostphere/Zero boost) from there ramp the timing down to say 15 on 5lbs and 10-12 on 10psi boost. MAKE SURE you are using non projected tip plugs like a BR7ef with a tighter gap (.16-.20) take is SLOW and have a friend with you to watch the wideband in case your AFRs get to high. I would say try to stay in the low 11s at first until you start leaning on it. I would personally put a smaller spring in the gate like a 5lb spring while youre learning so don't kill the motor.
The gear you have has gotta go unless you are running like a 30inch tire. I would say a 3.50 with a 28 would be nice even a 3.27 would be good as well.
Non intercooled is fine for low boost but if you plan on cranking it up you should either spray meth, intercool it, or mix race gas just to be safe.
When I used the MSD6010 I used the MAP sensor only to tune which made things a lot easier and the car ran great BUT you have to be careful that your MAP sensor is Always working. If not then your car will run say 32* all the way through and not pull down to the lower timing while in boost. I could be wrong on this but I don't think I am. I have had 2 map sensors fail on me (im assuming Heat in the engine bay) so be very careful. I have since upgraded to the Daytona Sensors box and Map sensor which I really like a lot. The tech support is great and the overall quality is a lot better than the MSD6010 unit. Hope this helps!
Timing: Run NA timing (30/32/34 just depends what the motor likes) up until 15psia on the map table (atmostphere/Zero boost) from there ramp the timing down to say 15 on 5lbs and 10-12 on 10psi boost. MAKE SURE you are using non projected tip plugs like a BR7ef with a tighter gap (.16-.20) take is SLOW and have a friend with you to watch the wideband in case your AFRs get to high. I would say try to stay in the low 11s at first until you start leaning on it. I would personally put a smaller spring in the gate like a 5lb spring while youre learning so don't kill the motor.
The gear you have has gotta go unless you are running like a 30inch tire. I would say a 3.50 with a 28 would be nice even a 3.27 would be good as well.
Non intercooled is fine for low boost but if you plan on cranking it up you should either spray meth, intercool it, or mix race gas just to be safe.
When I used the MSD6010 I used the MAP sensor only to tune which made things a lot easier and the car ran great BUT you have to be careful that your MAP sensor is Always working. If not then your car will run say 32* all the way through and not pull down to the lower timing while in boost. I could be wrong on this but I don't think I am. I have had 2 map sensors fail on me (im assuming Heat in the engine bay) so be very careful. I have since upgraded to the Daytona Sensors box and Map sensor which I really like a lot. The tech support is great and the overall quality is a lot better than the MSD6010 unit. Hope this helps!
03-17-2017, 03:32 PM
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Serioussn95 are you using a certain brand map sensor? How did you know it failed? I can see how that would ruin you day if it stayed at 32* at full boost! That would suck
03-17-2017, 04:01 PM
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My first one was off of amazon and the second was from Efi source. It appears that the heat caused them to delaminate for some reason. The new one is a Daytona Sensors and so far its working great. The only way I knew was because when I connected my laptop, I didn't see the MAP gauge reading any. I left it connected to the harness and hit it with compressed air, it didn't do anything so I knew it was bad. thank god I didn't make a WOT pass lol
03-17-2017, 09:29 PM
#13
Thanks for all the help! My rear tires are 29.5s so you reccomend 3.50 gears? Also my car running 11 on the wide band gauge (that's where it's idling at right now anyhow) is safe for now? Also I am running Ngk tr6 plugs right now.
03-18-2017, 06:26 AM
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Yes with that big of a tire the 3.50s should work well. 11s at idle is a little fat, try playing with the idle mixture screws to get it into the 12's low 13s.. Every carb is different so don't get hung up on the number BUT make sure when your checking your AFR at idle its when the motor is AT TEMP and in drive. I struggled with this for a while but eventually got it. LOW 11s even high 10s AFR at WOT is what your looking for right now. Remember you wanna Sneak up on the tune, not pop it first time out the gate. I would definitely change the plugs to a BR6 or Br7EF non projected tip for forced induction application.