removing cat converter...

[gkarmadi]

Hi,
I am currently running a hi-flow cat converter on my t2 along with greddy e-01 electronic boost controller (boosting 13psi on my td07 turbo). My question is if i would remove my catalytic converter and run a straight pipe, is there any danger to my turbo/motor (boosting higher than 13psi) or will my boost controller keep it @ 13psi??

[Max777]

boost controller will only allow higher boost, it will not prevent the car from overboosting. It will still open the waste gate at 13psi, but if the waste gate is too small (like on a stock ht-18 turbo) it will still over boost.

What kind of setup are you running? All I see is TD07... how about engine management?

[gkarmadi]

A bit info about my set up:
A T2 street ported motor
550cc/1600cc (primary/secondary injectors)
Denso (supra TT) fuel pump
Fc1000 ignition box for leading coils
Stock leading (7) and trailling (9) spark plugs w/ hotwire plug wires
"Trust" front mount w/ HKS ssqv blow off valve
3" turbo back exhaust (w/ hiflow cat)
Haltech E6K (w/ 3bar map sensor)
TD07-18a turbo, HKS manifold w/ HKS 38mm gate (6psi spring)
Greddy e0-1 boost controller

Running premix and emission system removed (except that cat)

[gkarmadi]

Car has been tune but only for 2hrs and run rich (need more tuning). @ 13psi wot I got low 10afr on my wideband.
I don't what's the whp (have not dyno yet) @ 13psi, but it did made 280rwhp @ 9psi

[Max777]

In that case, I would say that the wastegate is the only limiting factor to overboosting when you remove the cat. So, if it's adequate, and the spring in it is proper, then it should not be a problem as long as you configure the boost controller correctly.

Aaron Cake recently had a problem with the "Natural boost" setting on his car, where the controller was not engaging because he dialed it in for 13psi, and the natural pressure that the turbo made was around 12.4-12.6psi. Make sure you have this set correctly as well. :D

PS: how much time and money did you sink in that setup? That's nice!

[RETed]

Car has been tune but only for 2hrs and run rich (need more tuning).

I don't know why you're trying to get more boost when you're not even tuned for what you got now...?


-Ted

[gkarmadi]

I wasn't thinking of running high boost (yet). Atleast that's not my intention by removing my cat.

My question isn't clear (I guess). This is what I want to know:
" Is my motor/ turbo safe by reducing back pressure (ie; running straight pipe)
Will I have boost creep/spike/overboost?? I am running hks 38mm gate w/ atmospheric venting.
Is my greddy e0-1 keep me @ 13psi?? (Or will I see higher/lower psi on my boost gauge by simply removing cat)??
What happen to my afr (idle and wot)??
What's the drawback (negetive effect) from running straight pipe (when emission isn't a concern)??

Thank you

[Max777]

Well, I'm no expert, but as I already said, the reason for overboosting on a stock application when you change the exhaust is the lack of flow through the wastegate... the turbo is freed of a restriction, therefore it makes it's natural boost a lot easier. At this point, the factory wastegate actuator sees that the pressue has gone above 5~6 psi that it is designed for, and opens the wastegate bypass. However, since it's not big enough, this does not drop the turbine pressue enough, and you end up with boost hitting 8+ psi, at which point the factory fuel cut shuts down the engine...

With your setup, as I already said, it is not a concern. Why dont you take the cat out, and just see for yourself? You have a big wastegate, so flow should not be a problem, you have an aftermarket ecu so you dont have fuel cut anymore.

All that removing the car will do, is make the turbo spool FASTER, and yes, if you ran no wastegate, the pressure would be higher, but since you do, it will bleed off extra exhaust flow to the turbine once it hits the preset level, and stop if from going over.

Brian at BNR turbos ports the stock turbo wategate to roughly 38mm, which can handle 400hp, so I am making a guess that your setup should be fine.

[gkarmadi]

In that case, I would say that the wastegate is the only limiting factor to overboosting when you remove the cat. So, if it's adequate, and the spring in it is proper, then it should not be a problem as long as you configure the boost controller correctly.

Aaron Cake recently had a problem with the "Natural boost" setting on his car, where the controller was not engaging because he dialed it in for 13psi, and the natural pressure that the turbo made was around 12.4-12.6psi. Make sure you have this set correctly as well. :D

PS: how much time and money did you sink in that setup? That's nice!


I've running my set up for 3yrs (about 7000 miles). Not much time to drive it.
It also took about 3 yrs for the car make over (for the engine build, power modification and suspension make over) and about $10-15G in dough. I was sooooooo broke :(
This is also why I would rather ask first "what would happen to the car if I do this or do that" than just try it and see what happen. I don't have anymore spare money to spend on another motor build nor for a new turbo.

[Max777]

if you're that broke, why didn't you just go for the BNR stage 4? It's a hell of a turbo for the price, and it would have saved you some money over your current setup.

[gkarmadi]

The exhaust port of my motor is a bit big for a bnr.