i just installed a mp on my car the other day, and the boost is creeping....i haven't ported the wastegate. i have a PFC. i was wondering if a restrictor plate would work or if porting the wastegate would be better. i have dp, mp, cb, 99 spec turbos, y pipe, cai, and a streetport. also, if you know any wastegate porting walkthroughs, please send me the link....or even pictures...just so i don't **** it up....i already searched the forum for the walk through, and found nothing, so limit the flames

 

Restrictor or porting will work. One reduces flow and the other makes the wastegate sized for the flow.

From the FAQ:
Wastegate Porting:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-port-wastegate-426526/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/wastegate-porting-observations-726267/

 

porting the wastegate wont always work, as i have bnr stage 3 turbos with ported wastegate and they still creep. adding a restrictor plate is stupid, its the same if you had your stock cat in there, so why not just throw it back on there and save your motor... or if you want to keep the mp, get tuned for the creep.

 

You can't tune for creep because it doesn't stop. Yes you can rich out the fuel map all the way up to 100% duty cycle but you could still exceed fuel supply.

I do agree though with keeping the cat. That's never a bad idea for a street car.

 

depends on how bad the creep is, steve tuned me for creep, but i guess when i say thatit means he tuned me for 12psi.. mine wouldnt creep that fast, from 10 psi, would go to about 12 psi at the top of 4th gear. my injector duty was in the 90s with the stock injectors. god thing i got 1300ccs now, but im waiting for a retune and have it at 10 psi with the stock cat in untill i can get it tuned.

 

Restrictor plates + free-flow MP = counterproductive..

I'd suggest porting your wastegate and having your car tuned for your mods.

 

one thing I'm going to be doing. The wastegate isn't just limited by the diameter of the hole, but the distance the flapper can travel. I'm pulling my twins back out to hog out the cast iron behind the flapper arm, you can gain more travel that way. Also planning on smoothing out the flow path towards the wastegate inside the turbo runner.

 

port the wastgate. check rotary ressurection i think that site has a good walkthru in the ''how to go non seq'' part

 

That's not exactly true. While a restrictor plate will take some power away, it's far less restrictive than a 6-7" long honeycomb catalytic converter, or even a metallic substrate cat. Generally, people never notice the difference.

 

I used the other waste gate flapper ported to the max, and had max movement grinding it down and i still get creep with my street port. Im going to just port it till i can bearly see the hole under the flapper its rediculus

 

good info , thanks

 

I'm having a similar issue after installing a downpipe with the stock cat in place. My car is boost cutting when hitting 13psi at WOT pulls (most noticeable in 3rd, 4th and 5th).

Whilst it's starting to look like porting the wastegate is going to be unavoidable, will a EBC like a profec or similar assist with the problem?

From what I have read, porting the wastegate will not always resolve this issue.

Just to make sure, the best way to describe the problem is when doing a WOT pull in 4th, the car will hit a wall and make a loud BRRRTTTTTTT noise.

It is a 96 series 7, mods are a downpipe, HKS super dragger catback. Intake, cat, turbos, intercooler etc is all stock. No boost controllers or electronic devices like an AFC or similar.

 

I don't think you need to port the wastegate, I think you need to install a boost controller and get your boost set properly.

Boost creep is almost never seen on a car with a stock cat.

David

 

thanks for the quick reply.

I'm not sure if it would really affect the situation, i live in New Zealand which typically has a colder climate than where a lot of the members of this board are located. Would the colder/denser air perhaps cause the car to be more sensitive to overboosting?

at any rate, I'll look into a EBC since i'll need one later on should I go to a single turbo setup anyway.

 

Yes cooler temps tend to cause overboosting if the car's on the limit of the stock boost control.

But this is simple: if the car is overboosting and hitting fuel cut, and you've got nothing in place to dial it back down, you are overdue for a boost controller. Hitting fuel cut is considered to be very risky. First, a bad tank of gas will blow your engine before you get to the fuel cut. Second, who says fuel cut will always work in time?

Dave