Sponsored

FI and DI for 2018 5.0L

18psi

of boost
Joined
Dec 10, 2015
Threads
45
Messages
482
Reaction score
111
Location
Best Coast
Vehicle(s)
2021
yeah Toyota/lexus has their system figured out and working very well. theirs are some of the few DI engines that don't gunk up after 60-80k
Sponsored

 

Nuked

Well-Known Member
Joined
Sep 15, 2015
Threads
17
Messages
889
Reaction score
348
Location
Morgantown, WV
Vehicle(s)
2016 Triple Yellow GTPP w/Recaros
Vehicle Showcase
1
I just remember his posts. He has some extreme detail and knowledge. Always enjoyed reading his stuff even though I can't understand 3/4th of it.
Agreed, anytime I would see him post I knew shit was getting real! He had a very good detailed post on NASIOC regarding the FA20 and the DI, VVT etc. I can honestly say I learned a good bit and referenced back to that post often when tuning my WRX.
 

beefcake

Well-Known Member
Diamond Sponsor
Joined
Oct 18, 2014
Threads
1,416
Messages
12,181
Reaction score
4,661
Location
Bethel
Vehicle(s)
2018 Ford Mustang
higher compression just means being more conservative on the tune and boost.
 

EFI

Well-Known Member
Joined
May 19, 2015
Threads
62
Messages
4,791
Reaction score
4,047
Location
Masshole central
Vehicle(s)
5.Br0
The 12:1 is not a problem. They have supercharged and turbo gt350's that run 12:1 compression ratio.
The 5.2 bottom end is quite a bit more stout than that of the 5.0, so that comparison is relatively moot.
 

Jay-rod427

Well-Known Member
Joined
Jun 8, 2016
Threads
29
Messages
2,422
Reaction score
1,009
Location
Kansas
Vehicle(s)
2016 GT C/S
Higher compression and FI is less of a concern for centri/turbo cars as their boost curve is progressive. Unless using wastegates and higher boost lower setups. The PD blowers with hard hitting low rpm boost is a different story.
 

Sponsored

arghx7

Well-Known Member
Joined
Feb 3, 2015
Threads
3
Messages
284
Reaction score
94
Location
cold
Vehicle(s)
50 years Ecoboost
I recognize your name. You posted over on NASIOC a bit didn't you?
The one and only. engineer who makes really long posts when he's bored at work and done looking at snapchat stories :lol:

He's on nasioc, miataturbo, and many other places.
Many of us seem to go through the same cars throughout the years, or at least tuning them :D
yep. and rx7club (tons of stuff on rotaries). and 3000GT/Stealth international. and LegacyGT. (name was Boostin on there) and rx8club. and FT86club (good discussion of the PFI and DI systems on some posts I made there). and LS1tech (made some posts about the Gen V direct injection heads, only 2 valve pushrod DI engine out there), and mostly a lurker on supraforums. and the wolf web (functionally a blog on technical stuff). guess you could say I like arguing with people on the internet :headbonk:

Nasioc is a bunch of jackmonkies, Oh wait I came from there too! :D
:cool:

I just remember his posts. He has some extreme detail and knowledge. Always enjoyed reading his stuff even though I can't understand 3/4th of it.
if you don't understand something just say so. Like "I don't understand this, can you explain it in a different way?" one time I explained boost control restricter pills with a picture of a bottle of BBQ sauce :headbang:

Agreed, anytime I would see him post I knew shit was getting real! He had a very good detailed post on NASIOC regarding the FA20 and the DI, VVT etc. I can honestly say I learned a good bit and referenced back to that post often when tuning my WRX.
Glad somebody is reading it! I do engine performance, fuel economy, and emission tuning for a living. Started out as a guy tuning a shitty 80s car on a shitty Megasquirt 1 and moved into the industry.
 

arghx7

Well-Known Member
Joined
Feb 3, 2015
Threads
3
Messages
284
Reaction score
94
Location
cold
Vehicle(s)
50 years Ecoboost
Higher compression and FI is less of a concern for centri/turbo cars as their boost curve is progressive. Unless using wastegates and higher boost lower setups.
You can't buy a new car with a centrifugal blower, so that kind of belongs in its own weird category of boosted setups only available in the aftermarket. There are only so many centrifugal supercharged cars around and a lot of it depends on how well the kit was put together (how the compressor was matched, how good the intercooler is, pulley sizing) and how aggressively it's tuned. Have a competent tuner and a non-shitty kit is half that battle. Meanwhile, roots blowers (Camaro ZL1, old GT500) or Lysholm Twin Screw (Challenger Hellcat, old 5.4 Ford GT) are available with a warranty. So you can be pretty sure those setups weren't pushed too hard in the stock form, or at least has appropriate failsafes.

When you think of a turbo car with boost being progressive, you're thinking of Billy Bob's Fox body with a pushrod 5.0 and some bolt on turbo and manifold. They're not going to make boost at low speeds without a small turbine housing. Or you're thinking of very "oldschool" turbo cars, like a Mitsubishi Evo, which has a big twin scroll stock turbo relative to its engine displacement.

With any engine that has VVT on intake and exhaust cams, especially DI, the boost can come on much quicker because the valve timing can be changed to spool the turbo better. Intake cam advances when the engine is in vacuum to trap more air by closing the valve earlier. Then both intake and exhaust cams go into high overlap mode to spool, as fresh air blows right through the engine and spins the turbo up instead of being used in combustion.


The PD blowers with hard hitting low rpm boost is a different story.
This is a rule of thumb/commonly held believe that's kind of half true. The biggest problem again is that people get shitty kits with shitty or aggressive tuners. At lower engine speeds, up to say 3000rpm, the engine has a greater tendency to knock because there is more time for an extra explosion to occur in the combustion chamber. There is also a big risk of preignition from errant oil droplets or leftover bits in the combustion chamber. When Ford makes a GT500 with a roots, they set the pulley speed and boost so as to not push the charge air cooler too hard, and set torque limits if it overheats. They also run gazillions of hours at WOT in low speed/full boost to make sure it won't blow up. They design the crankcase ventilation and other hardware bits for boost, rather than boosting an engine that wasn't designed for it and might have trouble evacuating all those preignition prone gases.

Keep in mind that engines actually have a natural tendency to make less cylinder pressure at low engine speeds, even with flat torque curves--assuming you don't have severe knock or preignition. Here's what I mean by that. Let's look at the flywheel torque curve of the original Ecoboost 3.5 in a Taurus SHO or F150 (green line).

attachment.jpg


It's nice and pretty looking because it's run on an engine dyno at discrete rpm points and then a smoothed line is applied. Torque curve is almost completely flat (very slight gradient) from about 1800-4500rpm. So the torque hits hard at say 2000rpm. It should have a big spike in cylinder pressure there shouldn't it? That's what the internet said!! Well, no.

attachment.png


The dark blue line is the average cylinder pressure in the 3.5 Ecoboost engine at a given rpm point (dark green is the n/a 3.5). Even though the torque curve is mostly flat from 2000-4500 on the Ecoboost, the cylinder pressure keeps rising, until it flattens out. It flattens out because Ford engineers retarded the spark timing at high speeds to stay within the design limit of 80 bar cylinder pressure. So the engine runs less efficiently there, and you'd see an ugly "double hump" pressure trace in the cylinder shown below:

attachment.png


So the reason why your "low end roots blower torque is hard on the engine" thing isn't true because it works the engine harder or stresses it in normal operation. It's because low speed and high load is a riskier area for knock and preignition damage.

Good combustion at low speed produces lower cylinder pressure than good combustion at higher speeds.

Low speed areas are more prone to serious knock and preignition, which creates high rates of pressure rise in the cylinder and high peak pressures which can break things.
Ecoboost_Peak_cylinder_pressure_zpspb1xznpw.png
ecoboost_torque_curve.jpg
combustionphasing_1_zps6ca7921a.png
 

18psi

of boost
Joined
Dec 10, 2015
Threads
45
Messages
482
Reaction score
111
Location
Best Coast
Vehicle(s)
2021
thoroughly enjoyed that post :D

didn't know you started with ms1, was this with B6's or something older?
 

arghx7

Well-Known Member
Joined
Feb 3, 2015
Threads
3
Messages
284
Reaction score
94
Location
cold
Vehicle(s)
50 years Ecoboost
It was a naturally aspirated 2nd gen rx7. Biggest problem was the electrical noise filtering was bad on the MS1. And the tip in fueling code wasn't good either, so it was hard to accelerate smoothly. Of course at the time I didn't understand that because I had no sense of perspective.

Wide open throttle is one of the easiest things to tune on a car. Tuning All the other stuff is what separates the men from the boys. One of the best compliments you can ever get is to be told that your heavily modified vehicle drives and behaves like it's stock.
 

tampasnake

Well-Known Member
Joined
Oct 13, 2015
Threads
32
Messages
220
Reaction score
32
Location
Tampa, Florida
Vehicle(s)
Shelby GT350R
Thank you for your informative posts!

I like actually learning something reading this board for once
 
 




Top