You never want to drop compression. Period.

 

If you drop compression, you can run more boost... with out having to use Race Gas.

 

boost is overrated

 

lol huh?

 

i hope you have big plans for your tranny, or a bus pass.

 

In your opinion, what do you think the point of failure would be at that power level on this transaxle?

 

i want a kit... where can i send my money I DONT WANNA WAIT!!!!!!!!!!!!!!!!!!!!!!

 

60 lbs injectors with a return-style and a Walbro 255 should be good enough as an upgrade to the fuel system.

 

No.

Once again; air flow > CSS.net

 

its definitly not as high as 450 if your at the track on slicks.

 

I was asking what part of the transaxle you thought would be weak link at 400 horsepower, in your experiences.

 

Not to go off topic, but I was peicing together my plans to build the engine and trans to 400WHP. I had all the angles covered and I was all set to go crazy while the car is put away form the winter....BUT...then I turned on my brain... My car will NEVER see the track, I dont street race, I obey the speed limits...WTF do I need 400WHP for??

The real answer - and most wont admit it - is just to say that I have it...flaw of the male ego and the need to compete and dominate.

Soo...i have altered my plans. i am trying for an honest 280 - 300 WHP - a much more realistic goal and the car will still be quick as hell. i will upgarde suspension, wheels, chassis, etc - and make my car much more useable. My wife ( the voice of reason" asked me: "So how the hell are you going to lay that 400Hp down shredding your tires, genious?? You gonna run slicks around town??". yeah...she is right...basically, anything over 300WHP on this car as a daily driver is pretty useless IMO.

ANYWYAS...to get to the question..

For 300WHP, would I NEED to spend the money on this blower, or could I get my M62 blueprinted, rebuilt, ported, run a Dual Pass option B with Meth injection, supporting mods (60's Exhaust, etc) and a tune and make the HP figures? Or would I be "stupid" not to go for this?

Thanks for reading my crazy long post

-P

 

get the htv1320 and it will be easier to achieve. It has been done but you would not want to drive around all the time on that tune

 

Someone in your position, I would honestly wait a few weeks after release and see how the TVS reacts to the LSJ. It could only be a slight increase in power compared to the M62 or it may be one of those mods that are for the hardcore crowd, we can speculate either way but I don't think anyone wants let down in the end.

 

Witt: You and my wife would get along - the voice of reason I should have thought of that before posting

Thanks for the feedback!

 

That's just twisted and evil......I'm too old to wait for Santa Clause.....

Jim

 

i said to be on the safe side; you are maxing out 60's with 350whp w/ returnless, I'm looking for around 375whp and maybe track days might see race gas and a different tune so also what is our stock fuel pump rated to, 400hp? Yea you also notice they dropped compression on the LNF to 9.2:1; but then again 15lbs is what they come out with

 

Was bored and looking around to see if you guys had tried any of the TVS blowers yet and ran across the thread. Definitely sounds like a nice upgrade from the M62 with a lot more potential.


As for some of the fueling talk...
The SRT-4's change over to a return style fuel kit in order to utilize an adjustable fuel pressure regulator. This in turn allows for increasing static fuel pressure and/or utilizing a 1:1 ratio (psi boost:psi fuel) rising rate function to provide additional fuel flow required for higher boost. The old common "tuning method" on those cars (if you can call it that) was to increase fuel pressure mechanically by either raising fuel pressure and/or installing higher flowing fuel injectors and then using a piggyback fuel computer (S-AFC, DTEC, eManage, etc.) to alter the MAP sensor signal to trim out fuel where required. Crude at best with unwanted changes in timing advance due to altering the MAP sensor signal but it does work reasonably well if you're careful.

Now that the SRT-4's have the ability to reprogram the stock engine controller (SCT and soon Diablo) it's easier to stay with the returnless system. With it you're limited to static fuel pressure, meaning the regulator back at the fuel tank that's inline to and before the fuel line running to the rail doesn't increase fuel pressure under boost. That means the injectors generally have to be a lot larger in order to provide enough flow at high load/boost/WOT. There are a few high impedance injectors options up to around the 1000cc/min range (~100#/hr) that can be used on that car and can work reasonably well for some people.

There are a few downsides to a returnless system. First thing to emphasize like already mentioned is they were primarily implemented due to cost (i.e. simpler and therefore cheaper) and for emission reasons (minimize fuel vapor due to constant circulation and tank design in conventional systems). Some cars also use a PWM (pulse-width modulated) fuel pump that means the PCM can control the speed the pump turns and therefore alter pressure output but many cars such as the SRT-4 run a static fuel pressure controlled by a fuel pressure regulator inside the fuel tank pump module. It's possible to modify or change that stock fuel pressure regulator to run higher fuel pressure but since it's static you'll be constantly placing a higher demand on the fuel pump vice using a rising rate function via a regulator sitting on the return line that can raise fuel pressure and therefore increase flow under boost and run lower fuel pressure at light load cruising.

Most returnless rails incorporate a pulse-dampener to minimize the fuel pressure pulsing due to the pump. The return style setup generally has less pulsing and pressure variation inside the rails but many still use pulse dampeners. A concern on a lot of returnless rails is that there isn't even fuel distribution, but on a lot of rails they are not really hollow with a feed line slapped onto one end. Instead they'll have a smaller internal tube that alters inlet distribution to ensure adequate and equal flow to the injectors. Sometimes manufactures can also alter the PCM programming to provide different injectors pulse-width for certain cylinders if the rail, intake manifold, cooling system (and therefore combustion chamber temps per cylinder which affect resistance to knock), etc. cause one or more cylinders to run leaner than others or be more prone to detonation.

By using a return line system you can also size the injectors a little easier which can aid in tuning for drivability. On a big turbo car running high boost on a returnless system you'd need giant injectors to support a lot of power since the system can't raise fuel pressure under boost (to compensate for the air/boost pressure in the intake manifold acting against the tip of the fuel injectors). To effectively tune a returnless system you essentially have to have the capabilities to directly adjust injector pulse-width, such as with a stand-alone engine management system or flash reprogramming, and then have to run similar pulse-width/duty cycle as your stock injectors (say 85%) at WOT but then have to run comparatively much smaller pulse-width/duty cycle at idle and light load so the giant injectors don't flood the engine. With a return style system you could have fuel pressure increase under boost which can making tuning easier.

Other issues with a returnless system is that if you have a car with that type of fuel delivery system and need the flow of giant fuel injectors there may be other things like the feed line that will need to be altered in order to ensure adequate flow capability to get that fuel to the rail and those big injectors. Other issues like the pump support that fuel volume, filter restrictions, other bottlenecks, etc. may need to be addressed when the engine has a higher demand for fuel than stock. With a return style system you can sometime get around some of those by running slightly higher fuel pressure. Some claim there's also a possible advantage on keeping fuel cooler since it's constantly being circulated in a return style system but I doubt it's as significant as some people make it out to be since the fuel isn't going to be sitting in the rail for extended periods of time at WOT/high load.

 

anything over 350whp requires a return line...on almost any car to function properly

 

Witt, not sure if you know my tranny history or not.

With all my mods in my sig, I have managed to break two transmissions. It was 3rd gear both times too. One was on the street and was a downshift into third at 75-80mph, and the other was a upshift to third on the track and that one exploded and shot fragments outside the case! Needless to say I'm not too trust worthy of the these trannys. I have however found a compnay that builds SRT-4 tranny's and has done extensive work with the Soltice's and Sky's that said they could shot peen and cryotreat and do some upgrades to make the tranny stronger. Money and downtime is just a big factor though,

 

Helpful? Yes. Required? No. But you'll have a harder time with tuning on many cars.

 

A secondary inline pump controlled by an Aeromotive electronic FMU have been used at power levels far beyond 350whp with success.

Its pressure differential that dictates using a return line, not horsepower.

 

See my sig. I have a return-style with a Walbro 255 good enough to 500HP. That's why I told you 60's with Walbro 255 should be enough.

 

Hopefully it is lol.
My car goes into the shop this week to do the fuel system over and a few other little goodies. Trying to get a good amount of things done before march 1st so I can make it to the imports vs domestics showdown at e-town. Hopefully my clutch gets in early this week and the other stuff.

 

Very nice Paul, a return-style will benefit your setup. I received 4 days ago a stage 3 exedy just waiting for spring break to install.