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SRT Engineers Round Table: 05/25/2011

99K views 117 replies 35 participants last post by  chargerlover 
#1 ·
SRT Engineers Round Table Discussion

Wednesday, May 25th 5pm - 7pm ET

The ground rules:

  • First off, the SRT Engineers take time out of their busy schedule making go fast goodies to be here to answer our questions. Let's show them the proper courtesy and patience. There will be many questions and they may not be able to answer every question asked. If your question is skipped, please be patient as questions are not answered in order.
  • Please only ask one or two questions. There are lots of people who want to ask questions, so let's give everyone a chance.
  • Stay on the topic at hand. SRT Vehicles! Keep the off-topic chat to the other sections of the website. There is to be no discussion between members in this forum. Ask your question and enjoy the replies from the Engineers!
  • If your question has already been asked (by you or someone else). Don't re-post it in hopes to get it answered quicker.
  • Make sure you let the SRT Engineers know what model SRT vehicle you are driving or inquiring about. Yes, a head gasket is quite different between an SRT8 and an SRT4. :wink:
  • As much as everyone is salivating over what comes in the future, the SRT Engineers cannot answer any questions regarding future product.
 
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#46 ·
Front to rear ratio?

'09 Challenger SRT.

I want to put bigger tires on the back of my Challenger. How tall of a tire can I use in the rear, with stock on the front, without causing the computer to go nuts. I have heard some say 10% difference and I have heard some say 5%. Can I get a definitive answer from you guys? Remember, we are talking tire height, not width.

Thanks....BTW love this car, great job setting it up!
 
#58 ·
When track testing at the drag strip with Drag Radials, we generally run smaller rear diameter wheels (18"s) to facilitate a larger profile tire. If you don't closely match RPM of front/rear tire, you will eventually trip a check engine light for Pinion factor fault because front and rear will always run at different speed.
If you are just doing this at the drag strip track, don't worry about it.

'09 Challenger SRT.

I want to put bigger tires on the back of my Challenger. How tall of a tire can I use in the rear, with stock on the front, without causing the computer to go nuts. I have heard some say 10% difference and I have heard some say 5%. Can I get a definitive answer from you guys? Remember, we are talking tire height, not width.

Thanks....BTW love this car, great job setting it up!
 
#54 ·
Thanks for stopping by.

How much travel is in the 6.1L lifter? What is an optimum preload and what are the consequences to a preload that is greater or less of that optimum value? Thanks...Jonn
 
#56 ·
How much knock is normal on a bOne stock srt8 300c?I know a catch can helps reduce knock but not get rid of it totally..is there a certain amount the motor will tolernate before it decides to go on vacation.

gas is 93 octane from shell and bp at times..have you guys tested out which fuel works best in helping keep the knock down if it was an issue?


And the new 2012 300c srt8,is the touch screen navi/console swapable into the older 300c srt8s?

Sent from my T-Mobile Sidekick 4G
 
#68 ·
How much knock is normal on a bOne stock srt8 300c?I know a catch can helps reduce knock but not get rid of it totally..is there a certain amount the motor will tolernate before it decides to go on vacation.

gas is 93 octane from shell and bp at times..have you guys tested out which fuel works best in helping keep the knock down if it was an issue?

And the new 2012 300c srt8,is the touch screen navi/console swapable into the older 300c srt8s?

Sent from my T-Mobile Sidekick 4G
We recomment using pump premium fuel in the SRT and calibrate to that octane level. In the event the fuel quality is lower, the engine has knock sensors to correct the spark advance. At worst, you should hear no more than trace knock at part throttle & low speeds. If you hear loud knock at WOT, back off and fill up with good fuel.

The nav screens are different architecture and won't swap.
 
#61 ·
Given the fact that you guys are given a mostly completed painting, and asked to make it special (SRT) How often, if ever, are you stuck banging heads with bean counters or suits, or the government saying..."you cant do that", when you are just trying to make a bad a** machine?
"well, you said you wanted it special, didnt ya"
 
#65 ·
How about some specs between the 6.1 and 6.4 blocks for comparison

There was quick a bit of talk about the suspension changes made in the New Charger SRT

Are the mount points on the sub frames the same and the bolt on parts different ?

If the sub-frames are different will they swap over to the older cars ?

-R
 
#79 ·
How about some specs between the 6.1 and 6.4 blocks for comparison

There was quick a bit of talk about the suspension changes made in the New Charger SRT

Are the mount points on the sub frames the same and the bolt on parts different ?

If the sub-frames are different will they swap over to the older cars ?

-R
The bore and deck heights are different between 6.4 & 6.2 but Idon't have those exact specs with me. The water jackets are different and the 6.4L block has differnet oil passages due to MDS and VCT.
 
#66 ·
I don't think that this has been asked.

What are the four holes (approximately 3/4" Ø) in the upper area of the plenum of the 6.1L aluminum intake manifold? They seem to go into a space that leads nowhere. Thanks.
 
#67 ·
Thank you for taking your time to answer our questions, inquiries, and our curiosities.

When the Gen 2 SRT8s were being discussed and planned, did weight savings and Power output/ratings to contend with the competition ever come up to be a serious topic?
 
#74 ·
Yes. We spent considerable time on weight discussions. Doing drastic weight/structure changes from our carrier base vehicle causes huge development/impact risks so we were forced to use those carriers. However our team worked aggressively with the base teams to ensure the base structure incorporate HS Steel and other weight savings features to give us a good platform for our SRTs
The Gen2 SRT8s underwent rear suspension weight savings. On the engine side, we spent considerable time ensuring the active intake wouldn't cause us a weight hit.

We continually explore opportunities for additional weight that would help both base and SRTs as we all know less weight is more performance.

Thank you for taking your time to answer our questions, inquiries, and our curiosities.

When the Gen 2 SRT8s were being discussed and planned, did weight savings and Power output/ratings to contend with the competition ever come up to be a serious topic?
 
#73 ·
Any chance any of the SRT E geeks will be making any of the Modern Street Hemi Shootout events ?

We have the NMCA event in a week or so, LX&B in Ohio then Atco NJ

It would be nice to see some of you all at some of the events

-Robert
 
#77 ·
Any chance any of the SRT E geeks will be making any of the Modern Street Hemi Shootout events ?

We have the NMCA event in a week or so, LX&B in Ohio then Atco NJ

It would be nice to see some of you all at some of the events

-Robert
We've gone to the LX Nats for the past 2 years and have had a BLAST. We're planning on going back this year, but that's going to be a VERY busy month for us. Trust us, it's definitely on our schedule and we're coming back if we can.
 
#80 ·
The new 2011 392 shares the same throttle body (TB) as the previous 5.7's/6.1's back to 2005. I'll assume you do not have hard numbers handy (we did the simple math anyways), but can you recall at what point this TB might start to become a restriction?

In the same vein; can you elliminate the premise likely to be put forth that cost/budget restraints (during the design/test phase) meant utilizing existing data/existing fuel mapping/existing algorythmns surrounding the existing TB (and inventory) for the new 392.

As always, your information pushes us to explore the boundries of the 3G Hemi's and the platforms within which they reside. To this end we thank you profusely :^)

cheers
 
#89 ·
The new 2011 392 shares the same throttle body (TB) as the previous 5.7's/6.1's back to 2005. I'll assume you do not have hard numbers handy (we did the simple math anyways), but can you recall at what point this TB might start to become a restriction?

In the same vein; can you elliminate the premise likely to be put forth that cost/budget restraints (during the design/test phase) meant utilizing existing data/existing fuel mapping/existing algorythmns surrounding the existing TB (and inventory) for the new 392.

As always, your information pushes us to explore the boundries of the 3G Hemi's and the platforms within which they reside. To this end we thank you profusely :^)

cheers
We looked at larger diameter throttle bodies during the development of the 392 but they were only a small gain. Maybe more valuable when the 500 hp range is reached but you have to be careful about part throttle response. Each type of engine has unique fuel maps so we weren't saving on software or inventory.
 
#83 ·
Goodyear F1 Supercar tires not so super

I am now replacing my F1 Supercar tires after just 10,000 miles on my 2010 Challenger SRT8 and was wondering why Chrysler would put such terrible tires on their cars. The F1 is only good on dry warm days. I am replacing them with Yokohama Parada Spec-x. They out perform the F1 in practically every category and cost more than $100 less, each. Otherwise, thanks for the great car!!!
 
#94 ·
Ok so taking in the deck heights and chamber volumes, there shouldn't be an issue using them in a build ?

Because when I can manage my rebuild I wanted to do the 5.7 Eagle heads with the 6.4 Intake.

Just looking for mechanical interference issues more than anything else.

-R
 
#105 ·
Ok so taking in the deck heights and chamber volumes, there shouldn't be an issue using them in a build ?

Because when I can manage my rebuild I wanted to do the 5.7 Eagle heads with the 6.4 Intake.

Just looking for mechanical interference issues more than anything else.

-R
If you are trying to use a 392 intake manifold in a non-SRT vehicle, the 5.7L ECU won't be able to connect to the SRV controller.
 
#95 ·
Are you surprised that the adjustable suspension settings on the 2012 SRTs seems to have gotten little mention in the press?
 
#96 ·
If it was YOUR charger SRT8 (and it was not black) would you have the front fascia body colour or have the center section (in the grille area) black?
 
#102 ·
I would like to clarify a statement made at the Grand Cherokee SRT8 introduction in New York. It was stated that the Grand Cherokee SRT8 was electronically speed limited to 155 MPH. That is not correct. We do not speed limit SRT products. The Grand Cherokee SRT8 will go as fast as the engine will push it through the air.
 
#109 · (Edited)
what was the second gear tsb about my srt will not auto upshift in autostick i have tried everthing i can think of with a diablo tuner an i had the issue b4 i installed the tuner..thanks guys
 
#112 ·
soo that would fix it then?
 
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