How much boost is too much? (2025)

Unholy707

7000 Posts Club

Dec 14, 2024

9 Second Best E/T

HFCOTM

#1

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 14, 2024

#1

2015 stock long block. 2.69 upper on a max effort ported 2018 2.4 IHI, full race bearing rebuild (snout and bearing plate). I’m contemplating adding a 10% lower with the 2.69 upper. Is this too much boost? Too much rpm for the blower rotors? Are the rotors limited by bearings for rpm?



Forgedrod

Member

Dec 14, 2024

#2

Member ID
#17813
Messages
41
Reactions
87
Likes
12
City
Princeton
State
IL
Country
United States
Vehicle
2023 super stock
Dec 14, 2024

#2

8.9/2.69 x6400rpm=21,174. Stock with 3.35 upper ~ 15,600 at 6400 rpm engine speed. Pushing the limit imho.



vortecd

Poster Club Hall of Fame

Premium Account

Dec 15, 2024

Donating Member

9 Second Best E/T

HFCOTM

#3

Member ID
#1248
Messages
57,531
Reactions
196,958
Likes
402
City
Middleville
State
MI
Country
United States
Vehicle
2016 Charger Hellcat
Dec 15, 2024

#3

SDG has a graph it is on the site for rpm



vortecd

Poster Club Hall of Fame

Premium Account

Dec 15, 2024

Donating Member

9 Second Best E/T

HFCOTM

#4

Member ID
#1248
Messages
57,531
Reactions
196,958
Likes
402
City
Middleville
State
MI
Country
United States
Vehicle
2016 Charger Hellcat
Dec 15, 2024

#4



  • How much boost is too much? (7)1
  • Show All

GNBRETT

1000 Posts Club

Dec 15, 2024

#5

Member ID
#9039
Messages
1,399
Reactions
1,982
Likes
162
City
Kingsport
State
TN
Country
United States
Vehicle
Trackhawk, RS3, Golf R
Dec 15, 2024

#5

2.4's can be spun to the moon.



OP

Unholy707

7000 Posts Club

Dec 15, 2024

9 Second Best E/T

HFCOTM

Thread Starter #6

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 15, 2024

Thread Starter #6

GNBRETT said:

2.4's can be spun to the moon.

But how far is the moon? 😆



jonx96

4000 Posts Club

Dec 15, 2024

8 Second Best E/T

HFCOTM

#7

Member ID
#4957
Messages
4,364
Reactions
10,845
Likes
302
City
Small town
State
MI
Country
United States
Vehicle
2019 Challenger Redeye
Dec 15, 2024

#7

in the name of science I’ll be spinning one harder then that



  • How much boost is too much? (11)2
  • How much boost is too much? (12)2
  • How much boost is too much? (13)1
  • Show All

OP

Unholy707

7000 Posts Club

Dec 15, 2024

9 Second Best E/T

HFCOTM

Thread Starter #8

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 15, 2024

Thread Starter #8

jonx96 said:

in the name of science I’ll be spinning one harder then that

On a 2.4, stock long block?



OP

Unholy707

7000 Posts Club

Dec 15, 2024

9 Second Best E/T

HFCOTM

Thread Starter #9

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 15, 2024

Thread Starter #9

This will be for 9.6 seconds or less (hopefully) with cooldown time in between. Car has a chiller, e85



jonx96

4000 Posts Club

Dec 16, 2024

8 Second Best E/T

HFCOTM

#10

Member ID
#4957
Messages
4,364
Reactions
10,845
Likes
302
City
Small town
State
MI
Country
United States
Vehicle
2019 Challenger Redeye
Dec 16, 2024

#10

Unholy707 said:

On a 2.4, stock long block?

You asked about blower speed. But as far as being stock to many factors going into it. Sure you can. But the more you push the more potential for failure



  • How much boost is too much? (17)1
  • Show All

45-70govt

500 Posts Club

Founding Member

Dec 16, 2024

HFCOTM

#11

Member ID
#991
Messages
983
Reactions
4,225
Likes
182
City
Ghetto
State
NM
Country
United States
Vehicle
2017 Challenger Hellcat
Dec 16, 2024

#11

Unholy707 said:

But how far is the moon? 😆

The distance varies, but generally around 238,000 miles.



  • How much boost is too much? (19)1
  • How much boost is too much? (20)1
  • How much boost is too much? (21)1
  • How much boost is too much? (22)1
  • Show All

BULL

Oh NO! Not that guy!

Staff Team

Founding Member

Dec 17, 2024

U.S. Marine Veteran

Donating Member

HFCOTM

Wiki Contributor

#12

Member ID
#1079
Messages
16,239
Reactions
50,834
Likes
402
City
Weld County
State
CO
Country
United States
Vehicle
MY16 M6 Challenger Hellcat
HFCOTM
View Images
Dec 17, 2024

#12

When a rod puts an inspection window in the block, that was 1lb too much.



  • How much boost is too much? (24)2
  • How much boost is too much? (25)2
  • How much boost is too much? (26)1
  • How much boost is too much? (27)1
  • Show All

jonx96

4000 Posts Club

Dec 17, 2024

8 Second Best E/T

HFCOTM

#13

Member ID
#4957
Messages
4,364
Reactions
10,845
Likes
302
City
Small town
State
MI
Country
United States
Vehicle
2019 Challenger Redeye
Dec 17, 2024

#13

My rod disengaged when I went a few pounds to much 😂



  • How much boost is too much? (29)1
  • Show All

OP

Unholy707

7000 Posts Club

Dec 17, 2024

9 Second Best E/T

HFCOTM

Thread Starter #14

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 17, 2024

Thread Starter #14

jonx96 said:

My rod disengaged when I went a few pounds to much 😂

So I have a 2.69 on there now. Kong is doing a full port and race bearing rebuild. 108mm throttle body, and long tubes are inbound. Car has a chiller. Wondering if I’ll lose power without pulleying down a bit more, and what I can realistically pulley down to in the “safe” male rotor rpm range



F

fubar569

1000 Posts Club

Founding Member

Dec 17, 2024

9 Second Best E/T

#15

Member ID
#1073
Messages
1,347
Reactions
1,937
Likes
162
City
Bradford
State
PA
Country
United States
Vehicle
2018 Charger Hellcat
Dec 17, 2024

#15

You will not lose any power.

Blower, snout, 108mm alone should pick you up 50-80hp and gain 1.5psi give or take...which is fine because you'll lose it all with the headers anyway (and gain a few more hp there too).

I have all of that and run a 2.50 pulley on stock lower at the track. It'll be alright. Til it ain't.

Edit: before the long tubes/solo exhaust I had factory manifolds with AFe mids and factory exhaust. On a cool night I'd spin to 21-22psi max on the 2.50 pulley. Lol



  • How much boost is too much? (31)1
  • Show All

OP

Unholy707

7000 Posts Club

Dec 17, 2024

9 Second Best E/T

HFCOTM

Thread Starter #16

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 17, 2024

Thread Starter #16

I’m pushing 18-19 now stock snout /bearing plate/ throttle body( 2018 blower)



OP

Unholy707

7000 Posts Club

Dec 17, 2024

9 Second Best E/T

HFCOTM

Thread Starter #17

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 17, 2024

Thread Starter #17

I’m thinking maybe a 2.57 upper then (maybe) and leave it. Or a 2.65



F

fubar569

1000 Posts Club

Founding Member

Dec 17, 2024

9 Second Best E/T

#18

Member ID
#1073
Messages
1,347
Reactions
1,937
Likes
162
City
Bradford
State
PA
Country
United States
Vehicle
2018 Charger Hellcat
Dec 17, 2024

#18

I want to say my peak this year was 20.5psi on a 2.50 - I lost a solid 1psi overall going to LT's and catback all else being equal year to year. You'll gain 1-2 from the porting & 108 and lose some of it back with the exhaust.

You should be in the same ballpark. If you have the fuel you can pulley down just a hair more and get away with it.



  • How much boost is too much? (34)1
  • Show All

OP

Unholy707

7000 Posts Club

Dec 17, 2024

9 Second Best E/T

HFCOTM

Thread Starter #19

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 17, 2024

Thread Starter #19

I have so much of the car apart right now I’d put a cam in if I didn’t have to do springs and pull the heads. Didn’t realize until recently if just doing the cam you can undo the rockers, spin the cam a few times and push the lifters back into the treys



OP

Unholy707

7000 Posts Club

Dec 17, 2024

9 Second Best E/T

HFCOTM

Thread Starter #20

Member ID
#11903
Messages
7,911
Reactions
6,775
Likes
402
City
Orlando
State
FL
Country
United States
Vehicle
2015 Dodge Challenger Hellcat
Dec 17, 2024

Thread Starter #20

I really need to figure out how the heck to recycle coolant



You must log in or register to reply here.

How much boost is too much? (2025)
Top Articles
Latest Posts
Recommended Articles
Article information

Author: Terence Hammes MD

Last Updated:

Views: 6326

Rating: 4.9 / 5 (69 voted)

Reviews: 92% of readers found this page helpful

Author information

Name: Terence Hammes MD

Birthday: 1992-04-11

Address: Suite 408 9446 Mercy Mews, West Roxie, CT 04904

Phone: +50312511349175

Job: Product Consulting Liaison

Hobby: Jogging, Motor sports, Nordic skating, Jigsaw puzzles, Bird watching, Nordic skating, Sculpting

Introduction: My name is Terence Hammes MD, I am a inexpensive, energetic, jolly, faithful, cheerful, proud, rich person who loves writing and wants to share my knowledge and understanding with you.