Rexpelagi

Ok, so I just read through the 9 pages of the BP vs HBP thread. All I found about n/a motors was a blurb here and there (I apologize if I missed another thread on this, I couldn't find what I was looking for).

Basically, can anyone compare Stock vs Streetport vs HBP vs BP as far as performance/driveability is concerned?

What would be the prefered porting for best power? Lets assume that there are two seperate situations, one is a daily driven car, and one is mainly for track use (where driveability plays no factor).

I'm hoping the experts who weighed in on the other thread can shed some light on this too. Dyno sheets would be great, I saw the 188whp one from a street ported motor that was up a few weeks ago, anyone else have some to share?

Sideways7

iTrader: (7)

For a street driven car, a street port is your best bet, no question. It will yeild noticable power gains over a stock port, but it still has good driveability and low-speed manners. You can also still use the stock ECU with good success. With a good port job, and some other stuff like a CAI and good exhaust, you can get 160 to the wheels without too much problems, assuming it is on a fresh rebuild using new housings and s5 rotors. If you go with a standalone, you can start getting up into the 170-180 hp range, or even more with a good tune. My personal goal is 200 to the wheels, but I have to save for a rebuild first.
For the race car, if you have the money, a peripheral port would be your best bet. You would need a standalone, special intake, and ITB's to get the full potential out of it. With a lot of work and knowledge (and money), they can actually get up to 300 to the wheels. One that makes that much power would have very bad low speed drivability, a high uneven idle, and be deafeningly loud (like ears ringing even with ear plugs.)

Aaron Cake

iTrader: (1)

Stock port and street port: Basically drive the same. About 20% or more power gain on a steet port. Very little if any change in mileage, idle quality, etc. Probably still able to pass emissions. Good midrange power, good power boost up top.

Any bridge: Some loss of low end torque while making much more power up top. 200HP and more is easily possible. Requires standalone to function properly. Good luck passing emissions, some mileage loss, 1000-1500 RPM idle, requires free flowing exhaust (loud).

Rexpelagi

Thanks for the info so far, I guess what I more looking for in addition to the basic info is to see where each makes their power. I know bridgeports are high end oriented motors, but what exactly does the torque/power curve look like? Ideally Id like to see some dyno sheets if possible, that would really help me see what I would be getting myself into with each option.

Also, for me at least I have no emissions testing, so that isn't a concern, but Im sure it is for others so that is good information too.

Aaron Cake

iTrader: (1)

Look at a stock dyno graph, then shift the powerband past 5K. Then you have a good example of what a bridgeport looks like. Seriously, there aren't many bridgeport dynos posted that I've seen.

Rexpelagi

Ya that is what I am getting at, I mean I know someone has to have done this, I just haven't been able to find any dynos of anything except streetport and stock on an NA motor. This may be a sign... I guess maybe that people figure without the ability to rev the motor to 10,000rpm and really use the power from the bridgeport (my understanding is the stock tranny can not handle shifts that high, along with the flywheel and e-shaft possibly having issues). And at that point the cost/benefit ratio is just way out of proportion to be reasonable.

Sideways7

iTrader: (7)

Well, to my understanding the stock drivetrain is rated to 10.5k rpms, but you need a scatter shield past 8.5k. The reason you don't see many NA bridge dynos is because there really aren't that many out there, at least that I've heard about. The most common use for them is pure track cars, since they just aren't very well suited for the street.

idsigloo

Kahren streetported a N/A motor and is making 200whp. Has good idle and will only require fuel management. I would stick with Streetport.

Sideways7

iTrader: (7)

Didn't he use a 4-port block, though? If its the one I'm thinking of, it only got to mid 190's, too.

Rexpelagi

Is the 4 port block a good route to go? If I was looking at rotary resurection for my rebuild I believe they do that, would it be a good thing to do? The reason this whole thread was started is because I have an S5 with a blown motor, it needs a rebuild and I wanted to port at the same time (figured I may as well).

Also, as far as the driveline, I believe there was another thread where someone was saying how after only a dozen or so shifts above 8500 he killed a few synchros in the tranny. Basically he said the driveline could handle it, but the tranny couldn't take the shifts.

Sideways7

iTrader: (7)

I wouldn't use the 4-port block. The 6port has more port area and should have a greater power potential for a non-turbo. The only reason that car had a 4-port was because the owner wanted to turbo it later, then decided to stay NA.
If he blew the synchros after only a few 8500 rpm shifts, then either the synchros were about to go, or more likely he wasn't rev-matching. When you shift properly, you don't even need synchros. I personaly have countless 7500 rpm shifts, and the tranny is still running strong.

ericgrau

iTrader: (1)

How do you rev-match anyway? I'm still confused on this and I want to keep my tranny in good shape.

Sideways7

iTrader: (7)

You get the motor going at the right speed for when it is in gear. For example, if you are doing a full throttle run, when you shift to second your revs will be 5k rpm (just an example.) So you want to have the revs around 5k when you shift into 2nd. You dont have to get it exactly, just don't slam it into 2nd while its still at redline and pop the clutch out.

Rexpelagi

I see what your saying, so as long as you are careful (definitly would take some work, shift times are going to be a little longer) you can safely rev the engine up high and have the driveline take it. What about the engine itself? What can a stock 13B take?

I ask this because you would need to go high to get the benefit from an bridge porting correct?

Sideways7

iTrader: (7)

If you build a bridge port motor, it is no longer going to be stock. You will need to have it balanced to high rpm's, and do oil modifications and such.

Rexpelagi

At which point it undoubtedly becomes a much better option to either streetport it or spend the money it would cost to do a bridgeport right and do a TII swap/buy a TII, which I guess was the moral of the story to begin with.

Still would be interesting to see some bridgeported N/A dyno sheets though, if any exist.

anewconvert

iTrader: (1)

Once I get my car, get some fuel management and cash to tune Ill post up a SP/Aux BP Until then you are on your own. i havent found anything either.


BC

Rexpelagi

Good luck, I'll be looking forward to seeing how that setup works out. It would be nice to see some form of extreme porting on an n/a 13b, just for the heck of it.

For people who do go the streetported route on an n/a, do you normally keep the exhaust side stock or do you recommend some sort of porting there as well?

Sideways7

iTrader: (7)

I think it is beneficial to enlarge the exhaust port a little, but nothing too extreme. Thats a goog question for whoever does your porting. On mine, the exhaust was ported some, but I have no idea how much. I don't have a stock housing to compare it to.