Pump Gas boost vs Timing Opinion
Thread Starter
Teching In
Joined: Apr 2017
Posts: 13
Likes: 0
Pump Gas boost vs Timing Opinion All,
Im tuning my twin turbo 4.8 and am starting to get jittery on adding more boost. Ive read danmahs opinion of 14*/14psi being pretty successful but im unsure if he ran meth with that. Ive also read that less timing and more boost is potentially safer than high timing low boost. I want to drive this car somewhat reliably for alittle while before i turn it up. I plan on just reading the plugs after runs but its been raining its *** off and i haven't been able to.. Can i get pump gas timing/boost ratio opinions?
-gen 3 4.8 862 heads
-pac1218
-stock cam (higher compression with stock cam?)
- twin he351cw cummins turbos
Im currently at 14*/8psi. I know these turbos are made to be efficient around 21psi so im curious what direction you all would go in regards to 93 octane timing/boost.
P.S. Posting the build right now also if interested.
Thanks,
Im tuning my twin turbo 4.8 and am starting to get jittery on adding more boost. Ive read danmahs opinion of 14*/14psi being pretty successful but im unsure if he ran meth with that. Ive also read that less timing and more boost is potentially safer than high timing low boost. I want to drive this car somewhat reliably for alittle while before i turn it up. I plan on just reading the plugs after runs but its been raining its *** off and i haven't been able to.. Can i get pump gas timing/boost ratio opinions?
-gen 3 4.8 862 heads
-pac1218
-stock cam (higher compression with stock cam?)
- twin he351cw cummins turbos
Im currently at 14*/8psi. I know these turbos are made to be efficient around 21psi so im curious what direction you all would go in regards to 93 octane timing/boost.
P.S. Posting the build right now also if interested.
Thanks,
Put a 10gph meth nozzle in the charge pipe before the TB and run washer solvent and you can turn it up. 14* at 8 psi is pretty low. That 14/14 you mentioned is a good rule of thumb to be safe IMO and plenty of guys do it. Don’t go too low on timing though at higher boosts. It’s just as dangerous as being too high. It can hurt ring lands. Based on the 14/14 rule and pulling one degree per psi, keep the total at “28” (14+14). So at 15 psi you’d be at 13* and at 12 psi you’d be at 16*. Hope this helps. Start low, read the plugs and give it what it wants. Get that meth on there!
Thread Starter
Teching In
Joined: Apr 2017
Posts: 13
Likes: 0
Put a 10gph meth nozzle in the charge pipe before the TB and run washer solvent and you can turn it up. 14* at 8 psi is pretty low. That 14/14 you mentioned is a good rule of thumb to be safe IMO and plenty of guys do it. Don’t go too low on timing though at higher boosts. It’s just as dangerous as being too high. It can hurt ring lands. Based on the 14/14 rule and pulling one degree per psi, keep the total at “28” (14+14). So at 15 psi you’d be at 13* and at 12 psi you’d be at 16*. Hope this helps. Start low, read the plugs and give it what it wants. Get that meth on there!
All,
Im tuning my twin turbo 4.8 and am starting to get jittery on adding more boost. Ive read danmahs opinion of 14*/14psi being pretty successful but im unsure if he ran meth with that. Ive also read that less timing and more boost is potentially safer than high timing low boost. I want to drive this car somewhat reliably for alittle while before i turn it up. I plan on just reading the plugs after runs but its been raining its *** off and i haven't been able to.. Can i get pump gas timing/boost ratio opinions?
-gen 3 4.8 862 heads
-pac1218
-stock cam (higher compression with stock cam?)
- twin he351cw cummins turbos
Im currently at 14*/8psi. I know these turbos are made to be efficient around 21psi so im curious what direction you all would go in regards to 93 octane timing/boost.
P.S. Posting the build right now also if interested.
Thanks,
Im tuning my twin turbo 4.8 and am starting to get jittery on adding more boost. Ive read danmahs opinion of 14*/14psi being pretty successful but im unsure if he ran meth with that. Ive also read that less timing and more boost is potentially safer than high timing low boost. I want to drive this car somewhat reliably for alittle while before i turn it up. I plan on just reading the plugs after runs but its been raining its *** off and i haven't been able to.. Can i get pump gas timing/boost ratio opinions?
-gen 3 4.8 862 heads
-pac1218
-stock cam (higher compression with stock cam?)
- twin he351cw cummins turbos
Im currently at 14*/8psi. I know these turbos are made to be efficient around 21psi so im curious what direction you all would go in regards to 93 octane timing/boost.
P.S. Posting the build right now also if interested.
Thanks,
Apologies to the OP but I have recently wondered about the same thing. 14psi was my target as well on a SBE 4,8 with a single ON3 73/65 and a "stage 2" cam.
Is 14/14 with Meth and NO intercooler okay?
What about 14/14 with NO meth but with an Intercooler?
Last would be 14/14 with Meth and a Intercooler, would that be shorting the timing or boost or both?
Is 14/14 with Meth and NO intercooler okay?
What about 14/14 with NO meth but with an Intercooler?
Last would be 14/14 with Meth and a Intercooler, would that be shorting the timing or boost or both?
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Verdad Gallardo Won’t matter what fuel if you read the plugs. Timing on the strap, rich/lean on the bottom of the porcelain and heat in the threads will still show and if you’re running **** fuel and are too aggressive there’ll be piston on the porcelain.
I run nothing but 93 here but you never know when your gonna get a tankful of crap so best to tune conservative.
Agree with reading the plugs, they are never wrong. Just be prepared to make a pull and shut her down quickly so you get a clean read.
Now that I think about it a bit does running meth clean the marker on the plug strap?
Spider, So you don't run an IC or meth? Wouldn't you bump a few degrees if you did?
Agree with reading the plugs, they are never wrong. Just be prepared to make a pull and shut her down quickly so you get a clean read.
Now that I think about it a bit does running meth clean the marker on the plug strap?
Spider, So you don't run an IC or meth? Wouldn't you bump a few degrees if you did?
I run nothing but 93 here but you never know when your gonna get a tankful of crap so best to tune conservative.
Agree with reading the plugs, they are never wrong. Just be prepared to make a pull and shut her down quickly so you get a clean read.
Now that I think about it a bit does running meth clean the marker on the plug strap?
Spider, So you don't run an IC or meth? Wouldn't you bump a few degrees if you did?
Agree with reading the plugs, they are never wrong. Just be prepared to make a pull and shut her down quickly so you get a clean read.
Now that I think about it a bit does running meth clean the marker on the plug strap?
Spider, So you don't run an IC or meth? Wouldn't you bump a few degrees if you did?
I run an intercooler of course, just no additives like meth/alky/race gas etc. I don't like adding timing/boost with a meth kit because something in the kit can always fail. Use it for the cooling effect and this way if it craps out, you didn't add timing/boost to where it would knock.
this. This is my thought process also.
Staging Lane
Joined: Dec 2016
Posts: 82
Likes: 3
So with a carb; an intercooler and boostane professional in 91 octane gas may end up being a safer bet? Humm. Instead of depending on a water/meth injection kit. I was planning on 14# at 14 degrees of timing. 140000 miles on 5.3. Never regapped the rings.
Last edited by Stonerracing; Mar 7, 2019 at 07:30 PM.
- look at the heat mark on the strap to determine too much/little timing. Halfway between the end and the curve is safe.
- look at the heat on the threads to determine if plugs are too hot.
- use the loupe to look at the porcelain for signs of detonation. Black specks are a bad sign and silver specks are aluminum! You cannot see it with the naked eye and if you can hear detonation under boost, it's probably already too late.
- only way to tell rich/lean at WOT is to carefully cut the thread off one of the plugs and look at the ring at the base of the porcelain.
PITA, but the plugs are the only things to follow for tuning YOUR setup. Like others have said, run meth and run it straight to get the octane and let the plugs tell you how much more timing you can run. DO NOT trust pump gas or windshield washer fluid, etc, etc. With pump gas you want the additional octane from the meth, especially running a small displacement 4.8L with higher cylinder pressure.
I wouldnt. at 14psi on pump you better keep it around 12 degrees.
TECH Fanatic
Joined: Jun 2014
Posts: 1,533
Likes: 12
you guys using knock sensors at all? Mines set up to pull timing in relation to knock. It’s pretty touchy . I’ve had issues with false knock . Exhaust hitting frame etc...but it seems to work well. This is with a whipple 2.9 . Im Running 18* @13-14 lbs with 93 , meth /water. But the intake temps are relatively low. 25 over ambient usually.
TECH Addict
Joined: Dec 2004
Posts: 2,177
Likes: 627
From: Florida
dont be such a sally, 14/14 is pump gas no meth or water. i had a decent intercooler so i ran 14 psi at 15-16* no problem and ran up to 20psi in my 4.8 and 5.3. i used to daily on 31psi in my evo, 93 pump, ive never bought methanol in my life.
