Eddie91rx7

Hello , so I知 in the process of boosting my NA engine in my 91 convertible and I mostly have an idea of what I want to do. My power goal I would like to reach is 400 hp. I知 going to be running a Haltech and a slightly bigger turbo than stock but I was wondering what kind of Porting would I benefit from? I was thinking a Bridgeport but I致e heard streetport is better? Aside from the port I知 just worried about blowing my engine right away lol any suggestions?

Hayamate

These are my opinions and experiences. I'm no expert, I've just been building and racing this car in autocross for 3 seasons. If anyone sees anything wrong with what I say please correct me...

I think you'll need a turbo considerably larger than stock. A bridge port will get you higher HP numbers, but your lower powerband will likely suffer. I have heard that a bridge port will help to spool larger turbos. On a hybrid S5 60-1 turbo and street port, my 6-port S4 dynoed at 296/244 at 13PSI dropping to 11. That turbo was pretty small and constrictive, and the turbine was totally stock. When I switched to my BW S360 the spool RPM was about the same, but output vs boost was noticeably higher. I didn't get it back to the dyno before foreign debris took out my engine, but I would have guessed 350WHP at 12PSI.

One thing to be aware of is our lower threshold for detonation with higher static compression. There is a point where too much boost will cause pump gas to autoignite. I think that actual point depends on your turbo setup (turbo sizing and trim, manifold length), porting, environment, and quality of fuel. I'm certain it's possible for you to reach 400 (I'm assuming you mean WHP). I just don't think it would be safe on pump gas alone. At a minimum you'll want to run auxiliary injection to bring intake temps down. I run 500cc 30/70 meth water but only for safety. I tuned to my maximum torque, backed the timing down a notch, and turned on my water/meth for a cushion. Lots of people run aux. injection to make a decent amount of power over pump gas. I just don't have that much faith in it. I'm sure you could wire in a pressure switch to have the Haltech pull timing or boost if the system fails.

There's always E-85. But I've seen the results of some people running ethanol in their rotary engines, and it's not pretty. Allegedly the alcohol runs the housings dry despite the OMP or premix, causing premature wear. Even if E-85 was popular around here, I'll stick with pump gas and keep the timing conservative.

You may consider using stronger than stock apex seals. I'm using Rotary Aviation classic seals. They're not unbreakable, but they withstand more than the stock seals can. You might prefer to bend an apex seal during an unfortunate incident rather than the seal shattering and taking out half the engine. The trade-off is the rotor housings might not last as long as they would normally.

Use colder spark plugs. For ~300WHP 9 all around are okay, but you should go 10 or higher with more power.

I'm going for 400 myself this spring. Well, whatever 15PSI puts me at, but I'm predicting 400 or a little over.

EDIT: Welcome to the Club!

WondrousBread

This page is great when you're looking for a basic explanation. Since TII cars can reach 400hp on stock ports, I'd imagine you could definitely do the same with the larger ports on the 6 port engine. If you wanted to port it further you could, but I doubt it would be necessary.

As for the turbo sizing, I see a lot of people like the GT3582R. A bigger turbo will obviously get you more power with less boost, but will take longer to spool. A smaller turbo may become inefficient before you reach your goal. I suggest doing some searching for different dyno sheets around your target HP in the dyno section of this forum, seeing what people are achieving with different turbos before you make a decision there.

I have no first-hand experience in this particular area. However, there are people running 400hp engines on pump gas. Aaroncake's 6-port turbo bridgeport was making something like 500hp on 93? I don't recall how much boost he was running though. Anyways, this doesn't mean that auxiliary injection isn't a good idea, only that it may not be strictly necessary depending on how well it is tuned. The longevity of the engine is probably far more dependent on the tune and on proper maintenance. For the minimal cost and installation I would probably run an AI system myself.

Eddie91rx7

For starters I want to say thank you for such fast responses and good advice. As I seek more answers I知 going to try to provide you guys with more information. I知 going to be using Super Seals and a T04 Turbo along with the Haltech 500. After seeing the forum痴 recommendations I致e decided to Bridgeport my engine and run a 50/50 Water/Meth injection as well as High Temps are one of my biggest worries. Now I must ask a few questions , what injectors should I use? What intercooler would work best? I appreciate all the help greatly as this has been a dream project of mine that I hope to accomplish with hard work and all of y誕ll痴 help.

Dak

Your mind may already be made up but personally I would just do a street port. A bridge isn't necessary to reach your power goals. I don't know that the potential trade offs in drivability and engine longevity with a bridge would be worth it. Regardless of the port you still have the lower threshold for detonation to contend with. The water/meth injection should help with that. As too injector sizing I'd look to people setups who are making those numbers and the injectors they are running as a starting point.

Eddie91rx7

So after reading your response I completely agree with what you池e saying about the porting , as far as the injectors go , what are your opinions on 850 Primaries and 1600 Secondaries ? I also recently thought about using TII Rotors in my build but I would like know if there would be any benefit. Thank you everyone for all the help as I知 going to actually be building it next week I greatly appreciate it.

Dak

The lower compression rotors from the TII would be better since rotaries are sensitive to detonation. Should have a little bigger safety margin once you turn the boost up. I really have no idea on the injector sizing as I've not went down that road yet. In all my reading up on turbo stuff injector sizing is something I've not really looked at. I figured I'd cross that bridge when I got there.

Hayamate

I agree with Dak, TII rotors would be more advisable in higher horsepower applications. And a street port should easily get you to 400 on pump if you use lower compression rotors. From what I hear, bridge ports are a pain to live with in a street car. Gas mileage sucks, low end torque isn't great, you'll be smelling like fumes, and the exhaust will be louder. Again, that's just what I hear since I don't have a bridge port myself. But going from stock ports to a large street port I did notice these changes to an extent.

I think you'll be okay with the 850/1600 injectors and a good pump. Be sure to do your homework on what types of injectors fit. I had a heck of a time figuring that one out and gathering the correct grommets. Of course all that is moot if you're going to buy a kit specifically for the car.