another Paxton install done on 2001

Mike Adams

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Just tested another paxton installed on a 2001 Viper. This car had roller rockers, Mopar headers, Mopar Cat back, light weight fly wheel and 355 gears. On the test ride the air fuel ratio when as low as 11.1 most the time in boost was at between 11 an 12. I feel it is real important to make sure that you follow the final step in the instruction an check you fuel pressure and double check everything.
 
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Mike Adams

Mike Adams

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Customer just wanted his car it was raining the day we wanted to head to the dyno it has been driving it since. His car has never seen rain. I am organizing a dyno day this summer when they will all be posted
 

Vic

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How much did the customer pay for the work and parts?
 
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Mike Adams

Mike Adams

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That was a straight install with no extra's. Included road testing with a lambda guage installed. Extra's I would suggest AEM UEGO guage, and a boost guage. Bigger injectors and a Roe VEC 11 and can bring the hp up to over 700 hp. Then we could put on smaller pulley for more hp.
 

FE 065

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What about that Paxton rod that replaces the OEM aluminum crossbrace? "ab" on the GenI/II forum says he has excess wear on the inside of his front tires since installing the Paxton kit.


-Implying the frame is flexing more (inward due to engine weight?) because of that under-engineered rod that Paxton uses as a crossbrace.


And the frame would flex with rod ends on each end of the Paxton replacement brace..


One shop in CA has some kind of secret fix for it, but other than that, the issue has been ignored.
 
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Mike Adams

Mike Adams

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I have not had any problems like that. With the added weight of a blower and intercooler and a lowered car could also contribute to his wear issue. The bar also need to be really tight (hence the tie rod to adjust.) With the after cooler you are adding 100 lbs to the front end so he should double check his alignment
 

DChan415

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I have not had any problems like that. With the added weight of a blower and intercooler and a lowered car could also contribute to his wear issue. The bar also need to be really tight (hence the tie rod to adjust.) With the after cooler you are adding 100 lbs to the front end so he should double check his alignment


Also, I think its important that people make sure they install the tower bar with the car jacked up in order to put the proper pre-load on it. I haven't had any alignment problems with the bar installed.
 

FE 065

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All I know is last Sept. a Viper mechanic with tons of race team experience mentioned to me that they even see differences in front wheel alignment due to heat affecting the dimensions of the aluminum crossbar..


So I thought, "Man that crossbar's more important than I though"


Next I see the Paxton replacement piece with rod ends on the end of it...Rod ends are used mostly on the ends of tubular suspension pieces and by design they allow movement of the piece even though there's a mounting bolt through them.


Comparing the importance of the OEM sqaure tubing crossbrace to the rocking motion allowed if connecting each side of the frame with a rod that has rod ends on it doesn't present a pretty picture.


Danny, I don't follow your thinking. You mean you jack up the car and lengthen the tubular crossbar? How do you know how much to lengthen it? - You must lengthen it if it fits the car w/o jacking it up as delivered from Paxton.


Any kind of one bolt bar on each end is going to pivot.
 

2002_Viper_GTS_ACR

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FE 065, your hitting on a very good point. I am of the same mind, that this piece is inferior in design to the original unit. Its better then nothing, but its definetly far less rigid then the oem unit.

Here is another question around this, how come the oem one also grabs part of the chassis around the steering rack (making it a 3 point system), yet the Paxton unit only does 2 points. I know we all know the basics of physics and geometry, it a 3 point locking system is better then a 2 point.

Jon
 

RedGTS

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How does the Paxton bar compare to what Heffner and DLM have been using to replace the stock crossmember on their custom kits?
 

FE 065

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I don't think Heffner and DLM replace the bar at all.

Here's a pic of a DLM installation with the OE bar in place: http://www.fast-autos.net/dlm/stage46.html and I'm sure I've seen pics of Heffner's installation not using a different bar. That area of the car is very important. That beefy OE bar is a major piece of strength up there.


I'm not a chassis expert, but I'd be concerned with the additional stresses put on any other OE brackets and frame members in the front frame area when the OE bar is replaced with a couple short uprights connected by a crossbar with one bolt on each end.


The Viper's big front tires are right outside of that bar, and putting a lot of leverage on the frame in that area.


It just looks like linkage from a four link setup or something... Linkage being the key word. The Paxton bar just links the two frame rails together. Linkage allows movement by definition doesn't it?


All that Paxton arrangement is doing is making sure that both sides of the frame rock back and forth in unison. Each frame rail matching the other's movement thru the connection. I don't see any boxed rigidity in the new bar, only maybe that the twisting forces have to fight the strength of two joined frame rails rather than one. There's no boxing of the frame rails as the OE bar does.


.. I'd wonder too if the Paxton uprights coming up from the frame rails (unlike OEM) don't aggravate the situation by providing leverage for the twisting chassis forces, and increasing the strength of those forces. (?) Just like a longer ratchet increases leverage.


I'm not anti-Paxton btw... Had I not talked to that very experienced mechanic last Sept about something indirectly related, I'd had no idea that there was anything potentially wrong with the Paxton bar.
 

RedGTS

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Last I heard Heffner was replacing the crossmember:

You must be registered for see images
 

Joseph Dell

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On my DLM set-up, Doug does a fantastic job of both replacing and reinforcing the crossmember. Even in the pic above, if you look carefully, you can see how the crossmember is addressed.

On a stock viper, that crossmember runs _right_ through where the blower head-unit is...

JD
 

FE 065

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Could be..

Here's a partial quote from Dan Cragin's summation last fall of a Paxton system they installed:

" We have done numerous of these installs with great results. With any new product we have noticed a few things that can make this setup work better. The cars do run hotter, seem to have more chassis flex, and those with headers and no heat shields can run into some heat related electrical issues...."

He went on to mention a few fixes and cautions, but nothing else about the chassis flex... why else would there seem to be more chassis flex if not because of the Paxton brace?

SOTP measurements being not a 1:1 ratio, there must be alot of chassis flex worth knowing about but below SOTP sensory levels if someone out there noticed it from behind the wheel. What's that flex doing to other areas up front?

I wrote him about where I thought the the chassis flex was coming from and got no reply for months... Later a few days after I'd written Paxton about it, he sent me an email saying they had something they (his shop) were doing about the problem.


Whatever it is, it's extra cost, and evidently only known to him and those who bring their cars to him. Paxton hasn't announced any revised braces.


Your pic of the Heffner unit doesn't show alot. It seems to be a tubular unit, but it's low and sits directly in between the frame rails as the OE brace did. It may even be of the same general design as OE.

Maybe Heffner moved it a few inches but had the foresight to use the same design as OE. I haven't had the pleasure of seeing a Heffner or DLM install up close..
 

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