I cant find any info/reviews good or bad on the Pettit Y Pipe. I see that its a modified 93-95 but how does it stack up against the Efini Y Pipe?

Hi-Flow RX7 Y-Pipe

Thanks for the help,

Gary

 

pettit has been working on these engines longer than most people. Their upgrades are top tier, only part they missed on was their ast because it would warp on the neck but they have probably fixed that.

 

I know they have a solid reputation but from what Ive heard they have missed on their Steering Column Gauge Pod, Short Shifter, and Plateless 99 Front Bumper.

The Efini piece has got glowing reviews. I find it odd I cant find anything of Pettit's version

 

The Pettit version may be relatively new—and it's just a hand cut/welded OEM. The efini solves the flow issue address with moving the BOV bung (the welded patch), and also has the bolt-on cross-over pipe, so it was probably an easier solution. The larger BOV port may be the only thing "better" about the Pettit, but I can't say I've ever had any trouble blowing off (that's what she said) with the regular one.

 

One of the best things about the Efini pipe is that it removes the coupler. The Pettit unit doesn't do that. The Efini pipe is supposed to flow far better the 93-95 pipe. Mazda claims a 10 hp increase with its use. The Efini is a far better unit in my opinion.

 

I think the only advantage with that Y-pipe as opposed to the '96+ Y-pipe is the coupler itself. Some intercooler setups, especially super-large SMIC setups, need to use the old style Y-pipe. With this Y-pipe you can do that but still have some of the advantages in flow that the '96 Y-pipe gives.

That's probably why they made it, since they do have a large SMIC.

I'm not sure of the merit of the larger nipple for the BOV, it's hard to say if that really gives a benefit.

Dale

 

Respectfully from an engineering point of view,

Having a larger BOV port may be of little to no benefit at all, at stock boost levels. In fact, according to a personal friend of mine, Brett at GFB (the lead BOV engineer in house at GFB, Australia's largest BOV maker and exporter) the sizing of the BOV and its port has an effect on how much boost is exhausted, and then as a follow-on, how quickly boost is able to be rebuilt after that gearchange.

Too large a BOV (say you bolted a 600hp/30PSI supersonic BOV onto a dead stock FD) along with the larger BOV port pipe, you could find that it takes longer to rebuild all the boost you just lost at a gear change event. Their factory testing with SR engines and stock intercoolers in test cars on dynos, shows that venting as little as is only needed, (by placing the BOV before the intercooler) can still result in a very slight positive pressure being held in the small SMIC, which then hastens boost build up during the next gear.

What he's trying to tell me is that bigger is not always better with respect to venting of boost on a dead stock car.

Now a question for everyone else (because I dont know the answer): If the Enfini Y pipe is claimed to make a bolt-on near 10hp difference, thats good, obviously. But will a stock ECU be able to handle this sort of increase? Or will increased airflow from the turbochargers overtake what the stock injectors are driven to match, and will it then run lean under boost and go bang? IE should the Enfini Y pipe be kept away from cars running the stock ECU?

Because I realize that the Enfini Y pipe was introduced around the time they updated the ECU to 16-bit, there's probably a connection that the newer 16-bit ECU was programmed to handle new additions such as the 10hp Y pipe, yes? The old 8-bit 93'-94' ECU would not be able to match fuel delivery and it may be a bad idea?

If that statement has some truth, then that would mean it would only be a good idea to run the Enfini pipe on a car that has a Power FC or the newer style 16-bit ECU?

 

And having had a look at that Pettit Y pipe, it is interesting, but I fail to see how welding the side port off and moving it to the other side is going to allow very much of a difference. I might be missing something important about it, but unless they have flowbench numbers for a stock pipe vs the Pettit pipe, I dont believe that is the best use of your 150.00.