Running full exhaust w/ just Spec B
08-18-08, 05:40 PM
#1
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Running full exhaust w/ just Spec B
Can I run full exhaust (downpipe, midpipe, catback) as long as I have a boost controller set to 10psi to control boost, or does it not work like that and I will run lean? Only mods are non-sequential, richman ported wastegates, and boost controller, STOCK ECU.
Last edited by VanDahl; 08-18-08 at 05:58 PM.
08-18-08, 09:08 PM
#4
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Why do you HAVE to put the full exhaust on there?
Also, I really hope you aren't buying the cheap Ebay full exhaust and putting that on...
It's really hard to say if it will work. Every car is a little different. Only way to know for sure is to try it. If it doesn't work, leave the downpipe/catback and put the main cat back on - that will take all of 1 hour tops to do. You're going to have to do some experimenting.
Even smarter move would be to just leave the main cat in place for insurance and keep the midpipe in the garage until you get a PowerFC for the car. Do it right, my friend.
Dale
Also, I really hope you aren't buying the cheap Ebay full exhaust and putting that on...
It's really hard to say if it will work. Every car is a little different. Only way to know for sure is to try it. If it doesn't work, leave the downpipe/catback and put the main cat back on - that will take all of 1 hour tops to do. You're going to have to do some experimenting.
Even smarter move would be to just leave the main cat in place for insurance and keep the midpipe in the garage until you get a PowerFC for the car. Do it right, my friend.
Dale
08-19-08, 12:14 AM
#6
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like look at the one i am trying to buy...i cant put on the downpipe without also having the midpipe, i mean wtf!!!
http://www.rx7store.net/product_p/dpfd3s.htm
it says "Please note this downpipe does not work with the stock catalytic convertor." So how am i not supposed to run full exhuast, i have to!
Last edited by VanDahl; 08-19-08 at 12:21 AM.
08-19-08, 04:34 AM
#7
Just because something is for sale does not mean it's a good idea to buy it.
If you're serious, you're going to be laughed at when you explain that's the reason you blew an engine and need to get it rebuilt.
Dave
PS: Starting a thread does not mean you deserve to collect a whole bunch of responses. If you need more responses, run a search and collect them yourself. The world is not out there to deliver everything to your door.
"Please note this downpipe does not work with the stock catalytic convertor." So how am i not supposed to run full exhuast, i have to!
Dave
PS: Starting a thread does not mean you deserve to collect a whole bunch of responses. If you need more responses, run a search and collect them yourself. The world is not out there to deliver everything to your door.
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08-19-08, 06:09 AM
#8
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Why do you HAVE to put the full exhaust on there?
Also, I really hope you aren't buying the cheap Ebay full exhaust and putting that on...
It's really hard to say if it will work. Every car is a little different. Only way to know for sure is to try it. If it doesn't work, leave the downpipe/catback and put the main cat back on - that will take all of 1 hour tops to do. You're going to have to do some experimenting.
Even smarter move would be to just leave the main cat in place for insurance and keep the midpipe in the garage until you get a PowerFC for the car. Do it right, my friend.
Dale
Also, I really hope you aren't buying the cheap Ebay full exhaust and putting that on...
It's really hard to say if it will work. Every car is a little different. Only way to know for sure is to try it. If it doesn't work, leave the downpipe/catback and put the main cat back on - that will take all of 1 hour tops to do. You're going to have to do some experimenting.
Even smarter move would be to just leave the main cat in place for insurance and keep the midpipe in the garage until you get a PowerFC for the car. Do it right, my friend.
Dale
08-19-08, 10:37 AM
#9
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Just because something is for sale does not mean it's a good idea to buy it.
If you're serious, you're going to be laughed at when you explain that's the reason you blew an engine and need to get it rebuilt.
Dave
PS: Starting a thread does not mean you deserve to collect a whole bunch of responses. If you need more responses, run a search and collect them yourself. The world is not out there to deliver everything to your door.
If you're serious, you're going to be laughed at when you explain that's the reason you blew an engine and need to get it rebuilt.
Dave
PS: Starting a thread does not mean you deserve to collect a whole bunch of responses. If you need more responses, run a search and collect them yourself. The world is not out there to deliver everything to your door.
PS: next time you start a thread im going to make you feel very un special too!
nah but for real back to topic, do flange sizes differ on different downpipes, bec i cant seem to find a site that offers a downpipe that connects up to the stock cat, or more like it doesnt tell you whether it works with stock cat, so if some work with stock cat, and others work with midpipe only...eh nevrmnd i figure it out!
08-19-08, 11:19 AM
#10
Actually I think I have firsthand experience with the product you're talking about.
I bought a downpipe from RX7store several years ago and when I tried to install it the bolt pattern was slightly off. The two bolts at the main cat were too close to each other to fit over the studs. Rather than grinding the holes larger, I returned it and got a Pettit dp that did fit. Some people bought the same downpipe and it did fit - barely. However, not long after that we started seeing midpipe-downpipe combinations being sold together. Reading between the lines, I think a vendor bought a whole bunch of these downpipes and they arrived with the holes incorrect. So to fix the problem they quit selling the downpipes alone and bundle them with midpipes that do fit. (I would have sent those downpipes out to a machine shop to check the holes and slot them if necessary, but what do I know - I'm only a mechanical engineer !?!). But here we are 5 years later and I still see vendors and ebay sellers peddling these downpipe-midpipe combos, and still I hear about them not fitting properly when used separately.
Unfortunately, the typical first-time downpipe customer does not usually not have their car prepared to install a midpipe too. If I were a vendor selling FD parts, I probably wouldn't carry this combination and if I did there would be plenty of warning to help customer avoid blowing their engines.
Dave
I bought a downpipe from RX7store several years ago and when I tried to install it the bolt pattern was slightly off. The two bolts at the main cat were too close to each other to fit over the studs. Rather than grinding the holes larger, I returned it and got a Pettit dp that did fit. Some people bought the same downpipe and it did fit - barely. However, not long after that we started seeing midpipe-downpipe combinations being sold together. Reading between the lines, I think a vendor bought a whole bunch of these downpipes and they arrived with the holes incorrect. So to fix the problem they quit selling the downpipes alone and bundle them with midpipes that do fit. (I would have sent those downpipes out to a machine shop to check the holes and slot them if necessary, but what do I know - I'm only a mechanical engineer !?!). But here we are 5 years later and I still see vendors and ebay sellers peddling these downpipe-midpipe combos, and still I hear about them not fitting properly when used separately.
Unfortunately, the typical first-time downpipe customer does not usually not have their car prepared to install a midpipe too. If I were a vendor selling FD parts, I probably wouldn't carry this combination and if I did there would be plenty of warning to help customer avoid blowing their engines.
Dave
08-19-08, 11:27 AM
#11
I have the Downpipe/Midpipe ebay combo on my car, the down pipe was pretty hard to get on, but it all fits and lined up great with the midpipe, and then to the Tanabe Exhaust I bought. I kinda wish I went with a more trusted brand name downpipe...
08-19-08, 12:46 PM
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Actually I think I have firsthand experience with the product you're talking about.
I bought a downpipe from RX7store several years ago and when I tried to install it the bolt pattern was slightly off. The two bolts at the main cat were too close to each other to fit over the studs. Rather than grinding the holes larger, I returned it and got a Pettit dp that did fit. Some people bought the same downpipe and it did fit - barely. However, not long after that we started seeing midpipe-downpipe combinations being sold together. Reading between the lines, I think a vendor bought a whole bunch of these downpipes and they arrived with the holes incorrect. So to fix the problem they quit selling the downpipes alone and bundle them with midpipes that do fit. (I would have sent those downpipes out to a machine shop to check the holes and slot them if necessary, but what do I know - I'm only a mechanical engineer !?!). But here we are 5 years later and I still see vendors and ebay sellers peddling these downpipe-midpipe combos, and still I hear about them not fitting properly when used separately.
Unfortunately, the typical first-time downpipe customer does not usually not have their car prepared to install a midpipe too. If I were a vendor selling FD parts, I probably wouldn't carry this combination and if I did there would be plenty of warning to help customer avoid blowing their engines.
Dave
I bought a downpipe from RX7store several years ago and when I tried to install it the bolt pattern was slightly off. The two bolts at the main cat were too close to each other to fit over the studs. Rather than grinding the holes larger, I returned it and got a Pettit dp that did fit. Some people bought the same downpipe and it did fit - barely. However, not long after that we started seeing midpipe-downpipe combinations being sold together. Reading between the lines, I think a vendor bought a whole bunch of these downpipes and they arrived with the holes incorrect. So to fix the problem they quit selling the downpipes alone and bundle them with midpipes that do fit. (I would have sent those downpipes out to a machine shop to check the holes and slot them if necessary, but what do I know - I'm only a mechanical engineer !?!). But here we are 5 years later and I still see vendors and ebay sellers peddling these downpipe-midpipe combos, and still I hear about them not fitting properly when used separately.
Unfortunately, the typical first-time downpipe customer does not usually not have their car prepared to install a midpipe too. If I were a vendor selling FD parts, I probably wouldn't carry this combination and if I did there would be plenty of warning to help customer avoid blowing their engines.
Dave
08-19-08, 01:23 PM
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Friend of mine never got to fix the ebay downpipe to its stock main cat, he had to install the complete line.
Then he thought the catback was really too loud for its taste, and re-install his stock muffler.
Now is running ebay DP+MP+Stock muffler and he's very happy, no creeping issue.
He considers buying the RE dolphin catback and expects to have to port his watsegate.
I personnaly have an unknown brand DP, with a very nice bend, that goes to the RX7store HiFlow Cat, and I have the ebay catback on. I'm happy with this set-up except for spike at transition that I'll address installing a MBC. I left aside in my garage the ebay DP & MP.
But honestly, we were both very impressed by the quality fo the products, and yes, the only but important drawback is fitment with other brands or stock items.
Then he thought the catback was really too loud for its taste, and re-install his stock muffler.
Now is running ebay DP+MP+Stock muffler and he's very happy, no creeping issue.
He considers buying the RE dolphin catback and expects to have to port his watsegate.
I personnaly have an unknown brand DP, with a very nice bend, that goes to the RX7store HiFlow Cat, and I have the ebay catback on. I'm happy with this set-up except for spike at transition that I'll address installing a MBC. I left aside in my garage the ebay DP & MP.
But honestly, we were both very impressed by the quality fo the products, and yes, the only but important drawback is fitment with other brands or stock items.
08-19-08, 05:41 PM
#16
i would rather play it safe and not do it. theres plenty of downpipes to be had that will work with the cat, i have a re amemiya one, very similair to the hks. i wont add a midpipe till i give in and buy a pfc personally. i want to pick up the one in the fs section kind of 
and buying ebay parts is just lame there decently priced stuff out there dont need to cheap out that bad.
and buying ebay parts is just lame there decently priced stuff out there dont need to cheap out that bad.
08-20-08, 12:11 AM
#17
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Once you get a sufficient boost controller and your wastegate is ported to meet the demands, you have control. But you still need to set your boost to a level that doesn't exceed or push your fuel supply. Stock ECUs = 10psi. Remapped ECUs w/ stock fuel system = 12psi, and so on.Dave
08-20-08, 10:51 AM
#19
No. Get tuned PFC (or the like) specifically for your car if you want a full exhaust. Get a fuel pump and tuned ECU if you want 12 psi. I've seen stock fuel pumps **** motors out if they're not running top notch. It really pushes them @ 12 psi and your fuel pressure drops. You can tune for it but it's better to just fix the problem.
08-20-08, 11:37 AM
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but if you can keep boost at the 10psi you would be able to do this correct until you were able to get a tune? like for me it would be on the drive to the tuner etc.. i just dont want to over stress my setup.
08-20-08, 11:48 AM
#21
Your better off running a high-flow cat (wont have boost spike, maybe creep of 1-2psi) or even a resonated mid-pipe. A straight-through mid-pipe is LOUD, raspy, will boost spike (assuming no or small wastegate porting and unrestricted exhaust), should require a pfc/tune and smells terrible.
Just some food for thought.
Just some food for thought.
08-20-08, 01:02 PM
#22
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well my wastegate is ported to the limit, and it would only be till i can drive to the tuner which would be 100 miles on the highway.. so i doubt id be in boost much at all.. i just dont wanna pop my motor..
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