Hey guys I know this has been beat to death but I haven't been able to find what I want. Has anyone or does anyone know of an hhr that is running 400ish whp and 375ish tq or anything similar to that.

 

Are you talking about on the Stock 2.0L SS motor and they added mods/tune? Or are you talking dropping in a crate motor?

 

From the General themselves...

"2008+ Hydra-Matic 4T-45E Transaxle Option Code MN5

Type: four speed front-wheel-drive, electronically controlled, automatic overdrive transaxle with electronically controlled torque converter clutch.

Engine range: 2.0L - 3.5L

Maximum engine torque: 221 lb-ft (300 Nm)
Maximum gearbox torque: 325 lb-ft (440 Nm)

Gear ratios:

First: 2.95
Second: 1.62
Third: 1.00
Fourth: 0.68
Reverse: 2.14"

They seem to be able to reliably handle horsepower ratings over 300, and back when the HHR's were in production, there was talk of GM putting 600hp to the ground through 4T-45E transmissions.

 

Well we have a member on this forum who has slightly modified his SS automatic. His tune is the important part.....making HP and Torque close to what you are mentioning. He 1/4 miles the car and "abuses" the hell out of it (IMO) and it is still running with the same engine and transmission with no repairs.

Runs in the low 12's if I remember correctly. He goes by the name, 2005HHRauto. Look him up.

 

350HP & 450' lbs of wonderful torque, provided by E47 Ethanol...

I've been beating up on my 4T45E for 6 years now.

Last time out at the track, 1.6s, 60' times, on slicks...
1.6s 60' times, are wicked abuse, on any trans...

Ive read that the 4T45E, holds up better, than the bigger 4T65E.
One shop owner states that he rebuilds, tons of 4T65E, & few 4T45E...

Mine shifts as good, as the day that I got it...

HPTuner settings have helped my 4T45E also, with my changes to
reducing shift times in half, from .250 seconds, to .125 seconds.
I've also keep torque reduction, at shift points below 3,000RPM.

I'm also running full synthetic Valvoline DEXRON VI ATF, because of the heat, created by all automatics.
Heat is the #1 killer of automatics, & only a full synthetic ATF, will save it, to live a long life...
As in full synthetic engine oil also, why would anyone not, want to run full synthetic, in everything you own.
This is the 21st century, after all.
I also put a pan on, that has a drain-plug, so that I can easily drain the ATF,
once a year, & the filter, every 2 years...

Also, don't run the 'sticky', super traction daliy street tires.
You don't want to 'dead-hook', all the time, on the street, spinning is fun,
& it will save your 4T45E from alot of stress...

 

Do you think the transmission could handle a zfr or a 5431 precision with a slow boost ramp. Like I said to hit 400ish whp but lower tq.

 

Yes...
If proper maintenance , & tuning, of the 4T45E is addressed...

 

Hoping posting in here 2005HHR is still subscribed and getting email notifications . Is there anyway if youn can share your trans tune either on here or DM please?

 

He hasn’t been here since May 2019, perhaps send a PM to him

 

Oldblue i tried, his inbox is full