Srt-4 Engine Tech Article

[dsm_mike]

Just thought you guys might want to know there is an article in the latest issue of Sport Compact Car magazine where they dissasemble an srt-4 engine. It is pretty interesting, and there are some neat pictures. I wouldnt have guessed the rods were deliberatly broken in half to make the rod bearing cap. I guess you learn something every day.

Mike

[hyracer]

That's probably the very same article in the latest addition of Hot Rod Magazine. Hot Rod goes on to say in the middle of the article that they actually tore apart an engine from a GT rather than the SRT4. A number of the car mags are sister companys and share their tech articles, etc.

Deen

[Dalite]

Also, if anyone is looking for a great paper on the 2.4L turbo engine, the SAE website has on available for purchase/download for $12.00.

It is SAE Technical Paper Series - Number: 2003-01-0410, titled "Turbocharging the Chrysler 2.4L Engine". It is a 378K file that prints out to 9 pages. 7 pages are actually the "meat" of the paper, with 2 being the Cover and the reprint info.

It is written by Garry W. McKissick Jr. and David M Schmidt of DaimlerChrysler Corporation. It includes descriptions of the various component design changes from the NA 2.4L that were contributed from a group of 10 engineers who designed the changed components.

The paper includes the following headings and subheadings:

Abstract
General Engine Description
(with 2.4L Turbo vs NA Power and Torque Graph)
Objectives
New and Redesigned Components
Pistons
Piston Rings
Connecting Rods
Valvetrain
Bearings
Intake Manifold with Manifold Runner Distribution Graph
Oil Pump
Balance Shafts
Lubrication / Coolant Routing
Water Pump - with Impeller illustration and Coolant System Schematic, as well as Turbo vs NA water pump graph showing pump speed to flow
Cylinder Block
Cylinder Head Gasket
Exhaust Manifold / Turbocharger
Cylinder Head Cover (Valve Cover)
Engine Controller
(Gives informative but BRIEF Explainations of the concept of NGC - Next Generation Contoller, ACT and TIP sensor operation, departure from Look-up based to Model-Based programming algorithms, using a Torque-Based boost control objective to give the same torque output; with no affect from ambient conditions such as temp, baro pressure, etc. It also briefly mentions the calibration optimized for premium fuel and how the NGC Controller uses sensors to modify engine operation when lower octain fuel is used.)
Conclusion
(A nice tidbit here "The DaimlerChrysler 2.4L Turbo engine was designed to significantly imorive the performance of the Chrysler PT Cruiser". Further stating "The Horsepower and torque are increased by approximately 43 percent and 51 percent , respectively, over the standard NA engine.")
Acknowledgements

I would like to see if I can get permission from SAE to post the article here, but I am not too hopeful of that outcome. Some of their papers of the same basic byte count cost $59.00 to download, so I guess the $12.00 price was rather cheap.

They also have papers there on many aspects of the PCM: communication protcol, Serial Data Communication Interface (SCI), diag link connector, networking concept, etc. Since some of this info will not be current due to the 2004 PCM changes (and the cost of downloading), I haven't paid to get these..... yet.

[GLH_TC 16V]

Hey, I know Garry McKissick Jr. He got me into the Shelby Dodge Automobile Club back when I was in University. I might be meeting up with him in September for the Great Lakes vs. Ontario chapter challenge. I'm going to start making a list of questions for him now, if anyone has any tech. questions let me know and I'll see if I can get the insider info.

[Dalite]

Marc,

It would be nice if he would allow us to post the full text of the paper on the forum. I still haven't called SAE yet to ask permission. It is a great paper and really squeezes a lot of info in a shory space.

David

[THier]

quote:Originally posted by dsm_mike

I wouldnt have guessed the rods were deliberatly broken in half to make the rod bearing cap. I guess you learn something every day.

Mike

I learned that from the issue also, I have heard "cracked rods" but had no idea what it meant, I don't consider my self uninformed, I had a ~800hp small block in my sand dragger, but that goes to prove you arew never too old to learn something new. Now the big question is how new is this procedure?
The two articles are not exact copies, the Sport Compact seems more technical
Tom

[3BarBoost]

quote:Originally posted by THier

I learned that from the issue also, I have heard "cracked rods" but had no idea what it meant, I don't consider my self uninformed, I had a ~800hp small block in my sand dragger, but that goes to prove you arew never too old to learn something new. Now the big question is how new is this procedure?
The two articles are not exact copies, the Sport Compact seems more technical
Tom

DCX had a media event in May where every magazine could rebuild a turbo motor and drive the cars. I expect other mags to have similar articles soon.

[Ptturbine]

The CRACKED CAP design is not new. It has been around for a few years now and the reasoning behind it is very simple. When a conn rod cap is drilled for the bolts and cut in half, the cap alignment goes off slightly( this is why all rod ends have to be honed to size). The benefit of the cracked cap is when the rod is snapped, the bumps and valleys of the crack will fit together only one way. When this configuration is torqued together, the pieces actually become one(in a matter of speaking) This makes the resulting assembly very strong. Hope that answers that question.