 port/polishing a 5sfe, characteristics and bennifits? |
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 Apr 12, 2004 - 11:10 PM
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 Enthusiast  Joined Sep 4, '03 From Twin Cities MN Currently Offline Reputation: 2 (100%)  |
Im debating whether or not to have this done. I truly dont know exactly how this works, or what is done to what, but i'd like to know because it has been thrown at me to add a few hp. If anybody knows, does the characteristics of the engine change all that much? I'd assume a slightly quicker rev with a small loss in low end grunt for top end power- is this true? Also, where should I take my car to get this done? Im already getting my head gasket fixed at my toyota dealer- would they be able to do it when thats being done, or do I need to take it to a specialty shop? Anybody know how much one of these runs? Sorry for my complete ignorance on this subject but I'd love to gain the knowledge.
-------------------- Car #3: 98 Accord LX- purchased 5/06, totaled 8/06
Car #2: 95 Celica GT- purchased 8/03, current daily driver Car #1: 01 Focus ZX3- purchased 5/01, sold 8/03 |
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Apr 12, 2004 - 11:21 PM
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Enthusiast Joined Jun 13, '03 From brooksville,fl Currently Offline Reputation: 0 (0%) |
how bout for the 7a
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Apr 12, 2004 - 11:34 PM
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Enthusiast Joined Aug 21, '03 From Endicott NY Currently Offline Reputation: 0 (0%) |
What it will do is increase the amount of airflow. It won't do much on a stock engine. It's good for highly modded engines. It will take more work that just doing when changing the headgasket, the whole head has to be taken out, it takes some work. I'm sure you could find a shop to do it for about $1000-$1200
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Apr 12, 2004 - 11:37 PM
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 Enthusiast Joined Aug 29, '02 From Dallas, Tx Currently Offline Reputation: 0 (0%) |
Charactersitics for the 5s and 7a will be pretty much the same.....
Yup, you pretty much nailed it. You'll make more top end power, you may loose a little low end torque depending on how well its done. Porting is changing the shape, texture, or both, of the intake and/or exhaust ports in the head(s) to improve flow and make more power or torque. Porting is one of those things thats still somewhat of a black art. Its quite difficult to computer model the flow through an intake port and even more difficult to do so with an exhaust port. This means that modifications to them are basically done by instinct and are not always sound engineering. Anybody can port a head, but very few people do it right. It is very easy to hurt performance or driveability if its done wrong. Its important to keep the port area about the same unless you're raising the redline. Making the port bigger would help the engine breath better, but it wouldn't do so until well past the rev-limiter....and that wouldn't help much. The best method of porting for a moderate street engine is whats called 'pocket porting'. This method changes the way the air flows around the valve and valve seat and helps it enter the cylinder ('turn the corner') more efficiently. This is the area where you will find the biggest power gains without shifting the powerband out of range. I suggest you have it done by a shop that builds race engines (ala road racing or drag racing, but roadracers will build a more driveable head). Do not take it to an 'import tuner' type shop and have them do it. A good engine shop will likely have a guy who's only job is to port heads and he knows all the tricks of the trade. Prices vary quite widely but in general you get what you pay for. You can probably see some good gains for $300-$600 (just in porting, this doesn't count the valve job and parts to put the head back together). I highly suggest you get a 5-angle 'serti' valve job as this will help airflow a lot. You shouldn't need a lot of other parts, but if its a high mileage engine it might be a good idea to do a full head rebuild. If you're really serious and are going to spend some money on porting you should also have the valve stems cut down some. Again, this will improve flow. Make sure you quiz the shop on what kind of work they normally do, who they've built stuff for in the past, and what you can expect out of them. I wouldn't suggest having it done if toyota is taking the head off...they will likely not be very happy about working on anything that is modified, but you can always ask. If you're not going to remove/replace the head yourself, plan for extra cost there as well (unless you can get toyota to let you do it while everything is apart) |
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Apr 12, 2004 - 11:44 PM
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Enthusiast Joined Sep 4, '03 From Twin Cities MN Currently Offline Reputation: 2 (100%) |
thank you- i really apreciate advice from someone who knows what they are talking about. im going to have to decline on the idea- dosent sound worth it to me... too little for too much.
-------------------- Car #3: 98 Accord LX- purchased 5/06, totaled 8/06
Car #2: 95 Celica GT- purchased 8/03, current daily driver Car #1: 01 Focus ZX3- purchased 5/01, sold 8/03 |
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Apr 13, 2004 - 1:31 AM
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 Enthusiast Joined Dec 27, '03 From Nor Cal Currently Offline Reputation: 0 (0%) |
Tis the reason why I stray from topics that ask questions as these. You all know it's a performance modification... but have really no clue what it's about... or what it costs (price/time/tuning). As far as the general part of the question... the only real way to do it correctly... FLOWBENCH. It's not bigger better... it's velocity. -------------------- "It's ok to be naked girl... I'm an artist!"
1995 AT200 Celica ST: stocked out daily driver... 1984 AE86 Corolla GT-SR5: silvertop 20V 4AGE project car jacked up with goodies... 1991 SW2x MR2 n/a: bare bones hardtop model soon to be... |
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