a '98 4runner factory amp

I am sure i am going to need a vet with a lot of experience to answer this one.  I took the amp out of that 4 runner and wired it to reciece a an RCA input.  then i put the amp on my motorcycle with an i pod as the source.  i am using 2 channles of the amp to power 2 speakers that i have molded into the dash fairing of the bike.  here are the pics https://www.the12volt.com/installbay/forum_posts.asp~TID~122999~PN~1 .  I want to remove the rear seat of the bike and mold a box to house an 8in sub (memphis 15-mcp8s4).  my question is "is the amp stable if i were to bridge the last 2 channles together? If so how much power should it have?  I know it will be under what is recomended for the sub, but how far under?"  I dont give a damn about SQ, it is a motorcycle, i just want to be able to hear a bit more when i ride.  I also know if i do this i will have to build passive crossovers for the speakers and the sub.  at this point with no sub i am just using the eq in the ipod to take out all of the base from the full range speakers up front.  There are 2 reasons i am using that amp.  because i know someone is going to ask.  reason 1.  It is the only thing small enough to fit under the seat of my bike.  2.  it was $10.  from a customer with a 4 runner who added an aftermarked deck and i removed the factory amp for.  Trying to not spend much money on an audio install.  like i said it is a motorcycle. 

Thanks

Dan

If your cousin is such a good installer, and he will install anything for a 6 pack; why are you talking to me?

You can't bridge that amp. It's a BTL output amplifier, and tecnically, it's already bridged. You can't "bridge a bridge". You'll have to get a DVC 4-ohm woofer, and run the two remaining channels to the two individual voice coils on the woofer. They exist, but you might have to do a little bit of searching...

haemphyst wrote: You can't bridge that amp. It's a BTL output amplifier, and tecnically, it's already bridged. You can't "bridge a bridge". You'll have to get a DVC 4-ohm woofer, and run the two remaining channels to the two individual voice coils on the woofer. They exist, but you might have to do a little bit of searching...

Good information sir. thank you.  i was not aware that it was a BTL.  To be honest i had never even heard of that.  i had to look up what it even ment.  I spent about 5 years working in the biz, and am still learing stuff.  Just for my information, how did you know that it was BTL?  is there a way to test for that?  the speaker that i said i was looking at, is available in a 4 ohm dvc.  so that should work.  that does make me think of another thing that worries me. Correct me if i am wrong.  if i were to just take those 2 unused rear channles and and run them individually on each voice coil couldnt that create its own problems, since my amp is in sterio? couldnt the two outputs from the amp, potentially be sending differant signals to each individual voice coil and create problems?  i guess i could see if my ipod has a mono setting and that would fix the problem, but if it does not have such a setting, how would you fix/get arround that issue?

If your cousin is such a good installer, and he will install anything for a 6 pack; why are you talking to me?

Nearly ANY integrated, and EVERY OEM "hi-powered" amplifier in the car will be a BTL type circuit. It's how the manufacturers get "high power" without using a switch mode power supply internally to boost the battery voltage from the available 12V. Translation? It's cheap "power". As far as running "disimilar" signals to a DVC woofer, there is no issue. Run one channel to each VC, and you'll be all set. It's a "mixed" mono, rather than "summed" mono, but it will still work perfectly fine. For more information on DVC "problems" like this, read here: It pretty much covers it all! :)

Thank you for the help.  i expected to be waiting a long time for someone who could answer my questions, but you were on it quick.  My last question, and i know it would be more an educated guess, than an exact answer, but how much power do you think i would be putting to the sub if i do it  that way.  The reason i ask, is if the answer is to low, i may just scrap the idea.  no reason to put too low of power to it, under drive the sub, then me turn it up to high with not enough power and cause clipping.  then i have a blown sub and the whole thing was pointless.If your cousin is such a good installer, and he will install anything for a 6 pack; why are you talking to me?