Port and Polish vs. Tii swap
09-13-07, 01:16 PM
#1
Senior Member
Thread Starter
Join Date: Jun 2007
Location: Seattle Washington
Posts: 598
Likes: 0
Received 0 Likes
on
0 Posts
Port and Polish vs. Tii swap
My friend just got a 1986 vw gti 16v. He gave me a ride in it and it pulled harder then almost any other car I have been in. Dont worry, this isnt another "what can I do to beat this" thread. How big of a difference in pull will a port and polish give? I have ridden in a tii and I was in heaven. I know I will buy a tii down the road, but the only way I could right now is if I sell my GTU, and I dont think I will ever be able to. Will how hard a port and polished 13b pulls be comparable to that of a stock tii?
09-13-07, 05:05 PM
#5
New camshafts FTW!
Seriously, you'd need a lot of porting to the intake ports (bridge, peripheral, street, j-bridge, etc...) to start making power upwards of what a TII would give you stock. You'd also have to tear down your motor to port it and you might as well rebuild it while you're at it. If you search for those port jobs on the forum i'm sure you can find out how much power you'll be making and how much it will cost.
Seriously, you'd need a lot of porting to the intake ports (bridge, peripheral, street, j-bridge, etc...) to start making power upwards of what a TII would give you stock. You'd also have to tear down your motor to port it and you might as well rebuild it while you're at it. If you search for those port jobs on the forum i'm sure you can find out how much power you'll be making and how much it will cost.
09-13-07, 05:24 PM
#6
Really? I didn't know I need a bridge to make the same power as a TII stock.
A cone filter with cold air ducting, full exhaust, and tune would give you the same power as a TII stock.
OP: This isn't GT, you can't port and polish the cylinder head of an RX-7. (Well, there are some exceptions, but lets not get into that.)
A cone filter with cold air ducting, full exhaust, and tune would give you the same power as a TII stock.
OP: This isn't GT, you can't port and polish the cylinder head of an RX-7. (Well, there are some exceptions, but lets not get into that.)
09-13-07, 09:51 PM
#7
Lives on the Forum
-Ted
Trending Topics
09-13-07, 09:55 PM
#8
An NA with a reasonable condition engine and proper supporting mods (CAI w/ cone filter, full exhaust, aluminum flywheel, etc.) can at least keep up with a stock TII. With a fuel controller it would probably be faster. Of you could sell the car, put the money you would spend on that stuff into a TII and have a lot of room to grow.
09-13-07, 10:27 PM
#9
Senior Member
Thread Starter
Join Date: Jun 2007
Location: Seattle Washington
Posts: 598
Likes: 0
Received 0 Likes
on
0 Posts
I did ride in a turbo ii, (stock exhaust) and I was in heaven, it pulled harder then anything else ive ridden in (modded turbo mkiii supra). My intentions are to keep my GTU for the rest of my life (some of you might understand). I am planning on buying a tii with a blown engine and rebuilding it myself down the road, but I cant right now. I just wanted to know if I get it rebuilt, ported and polished by Atkins rotary, if the experience "pull" will be comparable to that of the tii.
09-13-07, 11:19 PM
#11
Lives on the Forum
If you thought the stock FC turbo was fast, an FC turbo with BPU will make you shat in your pants...
-Ted
09-13-07, 11:43 PM
#12
Yea, with a ported NA, you may get the same peak hp as a TII, but the shape of the curve will be much different. Relatively stock TII's make peak torque at around 3-4k RPM, at which point the torque begins to taper down a bit to the max power at 5.5 - 6k. A properly ported NA with a tuned intake will have a much peakier torque band, probably pretty high in the RPM range, so you really wont get that "shove" until you reach that torque band, and then it wont last nearly as long.
09-14-07, 12:42 PM
#16
Wow some harsh responses for such a simple inquiry.
The short end is that while porting will increase your performance, a turbo, evena small one, is going to go a long way. A turbo will have few downsides to normal driving. Porting however does affect part throttle levels, emissions, etc... The more extreme porting styles that allow you to make more power have even more street driven compromises. A really nicely setup turbo system on stock ports can outdo the best peripheral ported nonturbo engines with none of the drawbacks.
You can get an n/a as fast as a stock TII and still maintain a relative amount of streetability. However it'll cost you some good money. You wouldn't need a bridgeport but you would need a nice exhaust system, streetporting, perhaps a lightweight flywheel, and a few other misc things. This costs money and the powerband still isn't anything like that of a turbo engine. You will lack torque by comparison and will need to rev it up higher to get moving quickly. A stock TII really has no reason to go over about 6500 rpm or so and it's plenty quick up to that point. They feel totally different. Keep in mind as has been stated already, if you installed a free flowing exhaust system on a TII, power really goes up and the n/a won't stand a chance.
If you are looking for the acceleration of a completely stock TII and are happy with this, then yes it is possible to do with an n/a. It won't feel the same though. With a TII, if you ever want more power, it's very easy to get. With an n/a if you want more power, it's another engine rebuild with more extreme porting with more compromises and more money spent. A turbo is really hard to beat dollar for hp wise when it comes to performance.
The short end is that while porting will increase your performance, a turbo, evena small one, is going to go a long way. A turbo will have few downsides to normal driving. Porting however does affect part throttle levels, emissions, etc... The more extreme porting styles that allow you to make more power have even more street driven compromises. A really nicely setup turbo system on stock ports can outdo the best peripheral ported nonturbo engines with none of the drawbacks.
You can get an n/a as fast as a stock TII and still maintain a relative amount of streetability. However it'll cost you some good money. You wouldn't need a bridgeport but you would need a nice exhaust system, streetporting, perhaps a lightweight flywheel, and a few other misc things. This costs money and the powerband still isn't anything like that of a turbo engine. You will lack torque by comparison and will need to rev it up higher to get moving quickly. A stock TII really has no reason to go over about 6500 rpm or so and it's plenty quick up to that point. They feel totally different. Keep in mind as has been stated already, if you installed a free flowing exhaust system on a TII, power really goes up and the n/a won't stand a chance.
If you are looking for the acceleration of a completely stock TII and are happy with this, then yes it is possible to do with an n/a. It won't feel the same though. With a TII, if you ever want more power, it's very easy to get. With an n/a if you want more power, it's another engine rebuild with more extreme porting with more compromises and more money spent. A turbo is really hard to beat dollar for hp wise when it comes to performance.
09-14-07, 03:07 PM
#18
Really? I didn't know I need a bridge to make the same power as a TII stock.
A cone filter with cold air ducting, full exhaust, and tune would give you the same power as a TII stock.
OP: This isn't GT, you can't port and polish the cylinder head of an RX-7. (Well, there are some exceptions, but lets not get into that.)
A cone filter with cold air ducting, full exhaust, and tune would give you the same power as a TII stock.
OP: This isn't GT, you can't port and polish the cylinder head of an RX-7. (Well, there are some exceptions, but lets not get into that.)
09-15-07, 12:29 AM
#19
Senior Member
Thread Starter
Join Date: Jun 2007
Location: Seattle Washington
Posts: 598
Likes: 0
Received 0 Likes
on
0 Posts
so bottom line, I should do all of the minor mods that are covered under the beefy n/a thread besides port and polish until I have the money for a tii swap.
Would you recommend buying a tii with a blown engine and salvaging all of the parts and getting it rebuilt by atkins or buy a jdm/rebuilt/used engine and installing that and slowly swapping all the other parts out (like the rear end, transition etc)
Would you recommend buying a tii with a blown engine and salvaging all of the parts and getting it rebuilt by atkins or buy a jdm/rebuilt/used engine and installing that and slowly swapping all the other parts out (like the rear end, transition etc)
Thread
Thread Starter
Forum
Replies
Last Post
Azevedo
Other Engine Conversions - non V-8
26
03-01-19 09:19 PM
