Laggy and not crazy

[Aussie-up-north]

Hey Guys


Hope you got a minute to read over this and tell me what you think! As I have zero direction on what was to move forwards to get my 2015 5.0 Twin Hellion 55/62 BB turbos all dialled in.


I wanted to rule out boost leaks and maybe a stuck wastegate so I pulled the vacuums lines to the BOV and WGs and capped it off at the motor and the blow was still happening... I was being careful not to hit more than 11psi.


Motor is currently 9.5:1 compression still and built. 3c stall in front of the 6r80.


Basically when driving around town it’s super laggy/lazy drives just like a NA coyote... maybe a little low of the TQ side also... it’s unimpressive at anything under 3/4 throttle and or WOT.


When I leave from a light, I can ramp into half throttle and still see -5Inhg vacuum and the car shifts at 3-3400.


When I hold her on the break and stall her upto 3300 just before the tires want to break it will still be upto -11 inhg of vacuums.


Again all of this it will not BOV and WG full spring pressure.


When I give her the beans it will move out and get into boost hard... but. We all kid ourselves... we want the boost when we are just driving around the city.


The tuner said it’s on point.


Just to make sure I’m not crazy... I jumped in my buddies 2j merc with compression into the 8s and it was night and day. Just leaving from a stop and 1/4 - 1/3 throttle the single 6466 comes in hard... just driving around you can fell the zero effort getting to 60!


So... what could be going on here. Is it a bad match in components.

1. With this 9.5:1 compression should it of been a single turbo? Maybe twin smaller turbos?
2. Maybe the coyote will not perform good at 9.5 compression at anything other than WOT. And thus I should lift my compression?
3. Or do you think something is actually wrong. Car drives and sounds healthy.

Target power goal is about 900 to the tire.

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[awdtsi]

It's because of the stall. I have a similar setup with stock compression and the car is extremely docile at part throttle. I think it's slower than stock to be honest. It's just the nature of the beast. If you want it to feel more lively at part throttle you'll have to go back to a stock stall. At full throttle I see full boost (10-11psi) around 4 - 4.5k rpm for reference. I have 6062's and ran a 9.6 @ 142.

I can build about 1 psi on the foot brake though with my car but I do have a 2-step.

 

[gimmie11s]

They’re all docile until you romp on it.

Is this a serious thread?

 

[Aussie-up-north]

It's because of the stall. I have a similar setup with stock compression and the car is extremely docile at part throttle. I think it's slower than stock to be honest. It's just the nature of the beast. If you want it to feel more lively at part throttle you'll have to go back to a stock stall. At full throttle I see full boost (10-11psi) around 4 - 4.5k rpm for reference. I have 6062's and ran a 9.6 @ 142.

I can build about 1 psi on the foot brake though with my car but I do have a 2-step.

Good info on the stall you maybe right!

 

[Aussie-up-north]

They’re all docile until you romp on it.

Is this a serious thread?

Why would it not be a serious thread?

 

[Rjames18]

Sounds like a loose stall.

 

[kcc0521]

I had a 3c in my 2015 with 62/66 hellion sleeper kit and it felt much lazier with the 245 3c. I went to a 4r200 and 258 2b and it is a different car.

 

[3beeps]

It's probably lazy because it's a 9.5:1 motor instead of an 11:1 motor like it is stock. Needs the turbos to get it moving.

 

[Aussie-up-north]

I had a 3c in my 2015 with 62/66 hellion sleeper kit and it felt much lazier with the 245 3c. I went to a 4r200 and 258 2b and it is a different car.

Before the 4r200 when moving onto a highway at half throttle was it still lazy or did you see some boost? I take it your stock compression.

 

[Aussie-up-north]

It's probably lazy because it's a 9.5:1 motor instead of an 11:1 motor like it is stock. Needs the turbos to get it moving.

What would you guess to be a ”fix” to make this car more fun when cruising around town!

 

[BlackandBlue]

Bigger turbos are going to spin up slower than smaller ones. They will require more air/rpm vs small pumps.

The easiest solution to the problem if everything is working properly is to resize your turbos.

I learned this a long time ago in the Grand National days. We undersized out turbo because we lost so much on the hit vs a bigger turbo.

Garrett has a good dumb calculator but I would think 55s would make you much happier. https://www.garrettmotion.com/boostadviser/

 

[Aussie-up-north]

Bigger turbos are going to spin up slower than smaller ones. They will require more air/rpm vs small pumps.

The easiest solution to the problem if everything is working properly is to resize your turbos.

I learned this a long time ago in the Grand National days. We undersized out turbo because we lost so much on the hit vs a bigger turbo.

Garrett has a good dumb calculator but I would think 55s would make you much happier. https://www.garrettmotion.com/boostadviser/

I’m 55/62 are you thinking 55/55? I’ll play with this calc :-)

 

[sigintel]

Sounds like you need the turbine side to extract more work energy at lower RPM and expend that energy via compressor wheel building more boost(moving more volume as well).

Converter slip: allows higher engine rpm at same load, thus “pumping down” the intake pressure more than stock.

Cam timing: You may also be losing pressure if cam timing is allowing higher “blow thru” valve overlap at lower rpm. If phasers locked out, you may need tuner to bring these back into play.

Turbine/compressor map?: calc the flow rate and pressure for a couple points:
Redline
Peak HP
Peak torque
Stall
Then check turbine and compressor maps. If not available from your turbo vendor, use maps of same size turbine/compressor from larger vendor.
Try Garrett and BorgWarner online calculators?

Can you swap turbine housing for lower A/R(more restrictive)? Some vendors have swappable housings available fir the same core.

Cant find any A/R info on a 55/62. Was this turbo intended for use w a rally type turbine spooler?

*check both turbo shafts for bearing play or bad bearing causing either or both to lag spool.

 

[Aussie-up-north]

Sounds like you need the turbine side to extract more work energy at lower RPM and expend that energy via compressor wheel building more boost(moving more volume as well).

Converter slip: allows higher engine rpm at same load, thus “pumping down” the intake pressure more than stock.

Cam timing: You may also be losing pressure if cam timing is allowing higher “blow thru” valve overlap at lower rpm. If phasers locked out, you may need tuner to bring these back into play.

Turbine/compressor map?: calc the flow rate and pressure for a couple points:
Redline
Peak HP
Peak torque
Stall
Then check turbine and compressor maps. If not available from your turbo vendor, use maps of same size turbine/compressor from larger vendor.
Try Garrett and BorgWarner online calculators?

Can you swap turbine housing for lower A/R(more restrictive)? Some vendors have swappable housings available fir the same core.

Cant find any A/R info on a 55/62. Was this turbo intended for use w a rally type turbine spooler?

Awesome information!

This is what I got from hellion
That part number is for Precision 5562 billet wheel ball bearing turbos

PN/SM
10504207129

 

[BlackandBlue]

I’m 55/62 are you thinking 55/55? I’ll play with this calc :-)

Yes most likely. I don’t have a turbo coyote yet and there are guys on here with a lot more(and newer) turbo experience then me. We just had really good results with sizing our turbo for exactly what we were planning to do. 900 hp is an awesome goal but if street driving is what you are going to do, shooting lower with a much more responsive setup might be more fun.

I think it is kinda sacrilege around here to talk about smaller turbos but proper sizing is huge for street driveablilty.

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