AWD car FWD dyno

[Lunch_Box]

I was wondering if some people could help answer some quesitons about putting an AWD car on a FWD dyno. If you have a welded center diff can you just drop the transfer case since it does the same thing as a VCE? What is the HP limit you can put through an AWD car in FWD mode? I know that Tapp Auto has put at least 729 WHP on their 9 sec Talon. Now there is a AWD dyno in my area but I get free access to a FWD dyno when ever I want so I would rather save the $200 an hour or what ever they charge. The people that own the AWD dyno are DSM people so I called to see if they still had a VCE that they used before they got their AWD dyno. They told me that you shouldn't/can't put an AWD car into FWD mode with out breaking the tranny, you will get an improper/wrong tune if you dyno the car in FWD mode, and you will thow the tune off by dynoing in FWD.

 

[oztofrdm]

Yes if you have a welded diff. you can drop the transfercase and you can dyno it on a fwd mode.

Or you could do what we did the last time we had an awd 2g dyno, since we didnt feel like waiting for the exhaust to cool down we just took the driveshaft off and put a cap over the end of the transfercase just so oil wouldnt spill out of it. And this is the method that i will be using when i decide to dyno tune my car

 

[JOEY A]

AMS has been using a FWD Dyno for years until they bought there AWD dyno.

Guys at AMS say there is nothing wrong with dynoing in FWD mod

But it costs more to get your car tuned since they have to convert it to fwd, awd dyno made it cheaper now...

 

[Lunch_Box]

My car has a welded diff so it wont cost more and when you get free access to a dyno it will definitely be cheaper. So is there a HP limit the AWD tranny can handle in FWD mode? I thought everything would be fine and that this shop was just trying to me to dyno on their dyno.

 

[JOEY A]

AMS there used to be 2 drag 1Gs


One was White 1GA and the other was a red 1GA

Both in 9s I belive, and they used to be dynoed in fwd mod so im sure you fine

 

[Lunch_Box]

AMS there used to be 2 drag 1Gs


One was White 1GA and the other was a red 1GA

Both in 9s I belive, and they used to be dynoed in fwd mod so im sure you fine

Thanks for the help.

 

[GRNDSM]

If you have a welded center diff (or a VCE) and a switchable JDM transfer case, you can switch your car from 4x4 to FWD in less than a minute!

I did that for many years, until we got a bunch of AWD dynos in the area.

 

[topstreet]

If you have the stock transmission setup you should not dyno in fwd. The people you talked to are right. AMS was pulling the viscous couple and installing a locker shaft and VCE, like Leon said. If you already have the VCE and a welded diff or spool (like others are saying) drop the T-Case and go to town. If you do not have these parts do not dyno in fwd. The viscous coupler cannot and is not designed to handle the power, before transferring it. There for its going to act like a very violent clutch slip. This is the coupler attempting to transfer the power to the rear (which you removed.)

I hope this is a good explanation.

 

[Lunch_Box]

If you have the stock transmission setup you should not dyno in fwd. The people you talked to are right. AMS was pulling the viscous couple and installing a locker shaft and VCE, like Leon said. If you already have the VCE and a welded diff or spool (like others are saying) drop the T-Case and go to town. If you do not have these parts do not dyno in fwd. The viscous coupler cannot and is not designed to handle the power, before transferring it. There for its going to act like a very violent clutch slip. This is the coupler attempting to transfer the power to the rear (which you removed.)

I hope this is a good explanation.

The tranny I have is a TRE race build with a welded center diff. So if I have a welded center diff do I still need the VCE? The people that I talked to knew that I had a built tranny but when they started saying how I will be throwing my tune off by dynoing in FWD I started to shake my head and realize they must be desperate to get people on their dyno.

 

[GRNDSM]

The tranny I have is a TRE race build with a welded center diff. So if I have a welded center diff do I still need the VCE?

No, you do not. You need some way of locking your center diff. This can be done by a welded center diff OR a VCE, but not both. As a matter of fact, it will be virtually impossible to install a VCE on a welded center diff (unless they were welded together ).

 

[94Jettameowpsst]

Old thread but, when you weld your center diff as mentioned to dyno the car, is it meant for just that, or can you actually reliably drive it that way in fwd mode?

 

[dnhieu]

so if someone would have either a vic or a welded center diff someone would beable to drop the X-fer case and drive shaft and just drive up to the dyno? this wouldnt hurt the rear end at all would it?

 

[Lunch_Box]

Old thread but, when you weld your center diff as mentioned to dyno the car, is it meant for just that, or can you actually reliably drive it that way in fwd mode?

Why would you want to?

 

[Lunch_Box]

so if someone would have either a vic or a welded center diff someone would beable to drop the X-fer case and drive shaft and just drive up to the dyno? this wouldnt hurt the rear end at all would it?

You usually drop the transfer case at the dyno. Why would it hurt the rear end there is no power getting back there.

 

[dnhieu]

so what do you do with the driveshaft??? just let it hang there???

 

[Fayt]

That'd be fun.

Drop it to do some burnouts, reconnect to drop the fat ass end of your 2g launching it.

Only thing I can see it even affecting (not necessarily negative) is your transmission. The rear end would just be going along for the ride. Just disconnect, plug it up, and you should be good to go.

Love to hear a wiseman's thoughts on this!

 

[Lunch_Box]

Or if you want take out the front axles, plug the holes with some freeze plugs and you and a DSM drift car.

 

[na_turbotalon]

Or if you want take out the front axles, plug the holes with some freeze plugs and you and a DSM drift car.

I'd like to hear a wiseman comment on this. How much abuse can the rearend take?

 

[jtmcinder]

Since a 35/65 center diff sends enough to the rear to snap axles with just a t25, I can't see a welded-center "drift" car lasting too long without a lot of work on the rear end of the driveline.

With regard to driving a welded-center car around in FWD mode, I've heard of people doing this when they got sick of the skipping when cornering. He only hooked up the rear when he went to the track.

- Jtoby

 

[94Jettameowpsst]

Why would you want to?

For instance if you have a pooped out transfercase and cant find another one for your car

 

[funguy]

sorry to bring is thread back up.
i need clarification on this thread.
i'm planning to probably dyno tune my car, as it will just make it hell of alot easier than tuning it on the road as i have access to a 2wd mustang dyno.

1.if you have a welded center diff, then you just drop the driveshaft?
2. you can take just yank the driveshaft out, and use a VCE?
3. just drop transfer case totally with out any other mods?

are my questions correct?

 

[GRNDSM]

1.if you have a welded center diff, then you just drop the driveshaft?
2. you can take just yank the driveshaft out, and use a VCE?
3. just drop transfer case totally with out any other mods?

1. Yes.
2. Yes.
3. NO!!! Dropping the transfer case is the same as removing the driveshaft (or switching JDM transfer case to "FWD"). You also need to lock your center diff, ether by VCE, by welding or with a spool (just like you mentioned in #1 and #2)

 

[99gst_racer]

Leon,

When running a welded center, what do you use to plug the end of the t-case after you pull the driveshaft?

 

[GRNDSM]

I always used a JDM, switchable (there is also a JDM non-switchable version) transfer case.

 

[UnderPrssureDSM]

I always used a JDM, switchable (there is also a JDM non-switchable version) transfer case.

Where can I get one of those?