back pressure question !! PLEASE HELP!!!!!!

[boostedek9]

i have a 96 b18b in my 96 ek. i had a turbo d16y7 in it before i swapped it out. my exhaust is 2.5" all the way back to a ractive muffler. i have NO cat or test pipe or any thing. is this bad cars runs fine but hesitates a little when i take off and also when iam in like 3rd gear at like 2000 rpms and go to punch it it hesitates as well. but once i get passed like 3500 rpms i pulls like a mo fo.


1) would this problem be due to not enough back pressure?

2) what can i do to fix it?
please help. thanks in advance to any one who helps me

 

[Dr Tweak]

2.5" is fine for your setup. The whole backpressure being needed idea is a myth, what is lost with piping that is too big is exhaust velocity. Even so you should be fine with that size. It sounds to me like you may have an ignition problem, have you changed the plugs, wires, cap and rotor recently? Any CEL or codes stored in the ECU?

-Doc

 

[phunky.buddha]

Yaaaay someone else that at least has a basic grasp of fluid mechanics...

 

[Dr Tweak]

Yaaaay someone else that at least has a basic grasp of fluid mechanics...

I checked out your website, looks like you've got a nice shop. If you ever have Toyota swaps come in and need the wiring done quick and cheap, let me know. All the details are on my website: Phoenix Tuning - Home

-Doc

 

[AHHVTEC]

dont go over 2.5 you need back pressure unless your turboed

 

[civicious]

i have a 96 b18b in my 96 ek. i had a turbo d16y7 in it before i swapped it out. my exhaust is 2.5" all the way back to a ractive muffler. i have NO cat or test pipe or any thing. is this bad cars runs fine but hesitates a little when i take off and also when iam in like 3rd gear at like 2000 rpms and go to punch it it hesitates as well. but once i get passed like 3500 rpms i pulls like a mo fo.

With the problem you're describing, the first thing I would check would be your secondary ignition...rotor/cap/plugs/plug wires.

 

[boostedek9]

ok thank you. i have a brand new cap. i have not changed plugs wires or rotor. i do have a cel and it is a code 91. would that be a problem. i know its a fuel tank pressure sensor low input.

 

[Dr Tweak]

No, that shouldn't cause the problem. I'd go after the rotor and plugs first, if that doesn't solve the problem then the wires (rotor and plugs are cheaper and most commonly the problem).

-Doc

 

[boostedek9]

is there a way to get rid of this cel code 91 with out having to replace the tank and do all that stuff. thanks i relly appreciate the help.

 

[Dr Tweak]

I saw a thread on it a little while ago. Search around and I'm sure you'll find it.

-Doc

 

[civicious]

Low fuel tank pressure sensor input? You might try replacing your gas cap...

 

[boostedek9]

thanks guys for all the help. ill let you know what happens. with my problem.

one more thing. does anyone have base setting for a safc 2 on a b18b with t3 turbo and dsm 450s and a tial external wastegate set at .7 BAR (10 psi). if any one does will you be willing ot hsare them thank you

 

[civicious]

thanks guys for all the help. ill let you know what happens. with my problem.

one more thing. does anyone have base setting for a safc 2 on a b18b with t3 turbo and dsm 450s and a tial external wastegate set at .7 BAR (10 psi). if any one does will you be willing ot hsare them thank you

an SAFC is not sufficient to tune a B18B with 10psi...you need at LEAST an FMU (I can't believe I just said that) or something along the lines of Hondata or Crome.

 

[boostedek9]

so are you saying i need a FMU and safc. i just need it to run ok for two weeks or so. till i can get it dyno tuned and converted over to obd1

 

[civicious]

so are you saying i need a FMU and safc. i just need it to run ok for two weeks or so. till i can get it dyno tuned and converted over to obd1

actually, no...i'm saying you need to not boost until you can get it dyno tuned.


SAFC's and FMU's are hacks, and while they may work temporarily, in the long run you'll end up breaking something. I'm sure someone will post here saying 'oh buy my friend's brother's uncle's sister's cousin is boosting 30psi on an ITR daily driven with only an FMU and an SAFC'...but that kinda speaks for itsself, if you know what I mean.

Do it the right way, or don't do it at all. It'll pay off in the long run to wait until you can do it correctly.

 

[boostedek9]

ok thanks. heres what iam gonna do. iam gonaa convert to obd1 using only a obd1 p75 ecu and a obd2a to obd1 harness. after that how do i go about getting the ecu tuned to match the injectors and also to run 10 psi. in other words after converting to obd1 what do i need to do to get it tuned to 10 psi and be safe and reliable

 

[civicious]

ok thanks. heres what iam gonna do. iam gonaa convert to obd1 using only a obd1 p75 ecu and a obd2a to obd1 harness. after that how do i go about getting the ecu tuned to match the injectors and also to run 10 psi. in other words after converting to obd1 what do i need to do to get it tuned to 10 psi and be safe and reliable

Get an engine management system such as Hondata or Crome and take it to someone with a shop and a dyno and have them tune it.

What part of the US are you in?

 

[phunky.buddha]

I checked out your website, looks like you've got a nice shop. If you ever have Toyota swaps come in and need the wiring done quick and cheap, let me know. All the details are on my website: Phoenix Tuning - Home

-Doc

Thanks! It's not my shop though- I'm just really close in with the owner there, so I link to him as much as I can. They do wonderful work. They also hand wire almost everything.

 

[boostedek9]

iam located in washington state 1 hour north of Seattle. where are you located