I went for a test drive in a 93 touring I'm buying shortly. The car is in good shape and I'm getting it for a good price, but I decided I should check the boost pattern before buying it, just to be on the safe side. I plugged a crappy autometer gauge into the nipple in the middle of the top manifold (sound right?) and went for a spin. Here's what I saw...

At WOT in 3rd gear, the car makes an easy 10 pounds on the 1st turbo, then 8 psi on transition, then right back to 10 pounds until about 5500rpm. At that point boost drops to around 8 pounds until 7000rpm (which is where I shifted lol). The feeling in the car was of a slight drop in power at 5800 rpm. Does this sound right?

 

Most stock cars roll off to 8 psi at redline in 3rd. Does the car still have the stock pre-cat? I'm assuming it still has the stock main cat with those boost levels. What is the mileage of the car?

 

It has a Ntech high flow cat and M2 single tip catback... as far as I can tell it still has the precat. When does the boost normaly start to drop in a stock car though? Should it already be dropping by 5500 rpm?

The car has 111000kms so for you US folks, that's around 62000 miles.

 

Im running stock and thats about what I get.

 

Cool. I read on Robs site that I should be seeing 10psi until redline so I got a little paranoid .

 

If it still has the stock pre-cat, it's probably getting clogged or there is a boost leak. With a hi-flow and a cat-back, the car should be easily holding 10 to over 7k rpm.

 

yup, thats pretty much correct boost.

 

cool, an other fellow rx7 canadian with an FD

il va faloir que tu viennes faire ton tour au quebec avec ton monstre

is it one of those for sale on trader.ca? if so, which one?

congrats man, that will make what 2 or 3 rx7?

 

Nope it wasnt for sale on autotrader... I got it off a local friend.

I'm still concerned about that boost issue though. I did a search and it seems like half of you feel that it's normal and the other half say it's not. Like I said, boost on the secondary turbo seems to drop to 8pounds around 5500rpm.

Puma, this is my 4th RX-7 now .

 

droppping to 8 psi after about 6k rpm is ablolutely normal aas the stock exhaust cant flow efficiently at high rpm and like someone mentioned the pre cat might be gettign clogged thats why u get it at 5500. nothign to worry about.

 

I have dp, intake and catback and i'm seeing 8psi after 5500 rpm till redline. I know there is no boost leak cause i checked all the hoses and replaced couplers and stuff. I get 11-12 psi till 4500 then 8 then back to 11 and then at 5500 drops to 8 till redline. What's my problem there.