To Port or not to port!!

[John RX7]

hey
 
Ive decided to go single turbo,just having a read up on things on how to acheive my 450bhp goal,would i need to port my engine?,would it help in anyway?would i need to do a rebuild if i wanted porting,what porting should i go for? any good/bad experinces,any help is aprecciated
 
John

[BlitzBoy]

Yes you would need to port to a streetport level.
Yes the engine has to come apart for porting so yes you have to rebuild it.
Looking at approx 3K to rebuild with porting, plus the single turbo kit and ECu\\fuelling and cooling mods so another 3K on top.
So 6K in total

[PGiljevic]

hey
 
Ive decided to go single turbo,just having a read up on things on how to acheive my 450bhp goal,would i need to port my engine?,would it help in anyway?would i need to do a rebuild if i wanted porting,what porting should i go for? any good/bad experinces,any help is aprecciated
 
John

100% not needed ! for that power level or considerably higher.
 
Here is proof why >
 
Further to this post (stock V\'s street port)
 
Two RX7\'s both weight checked prior to running, both dyno\'s *varying methods* alone with vastly varying estimates of engine power! one matches reality (read other cars) the other is optimistic to say the least!
 
Stripped track car (13B-REW street port) Garrett single turbo 1.3bar
1> 1180kg (432rwhp DD! owners dyno shop estimates 509bhp!!!!!!!)
100kmh-200kmh = 8.3 seconds
 
Road car (13B-REW stock) Garrett single turbo 1.3bar
2> 1380kg (275rwkw "real power measure!" owner estimates honest 430bhp in this test)
100kmh-200kmh = 8.2 seconds
 
(same number of gearshifts, same OEM gearbox, same shift points.........) *both at sea level and std temp and pressure day* You do the maths power curve on one is far superior, but also some dyno figures are not worth the paper they are printed on
 
I do all kinds of porting from street port to peripheral and across more than I care to remember over years can honestly tell you that porting is 100% not necessary on any kind of road going 13B-REW *regardless of turbo size 400bhp to 800bhp* (and some track cars!) infact its actually a big backwards step in terms of speed (not just a token power print out of the peak "blip")

[dthebuk]

does the stock ported one not spool up the tub later in the rev range? pretty important for a road car.

Also what were the rest of the two cars in question set ups like?did different people map them? Who drove them?

also has one lasted longer than the other?



this isn\'t an attack btw, genuinely interested

[JBerg]

Hi Pete,
 
Good to see you on these boards
 
RR SP or go home lol.

[PGiljevic]

does the stock ported one not spool up the tub later in the rev range? pretty important for a road car.
 
Also what were the rest of the two cars in question set ups like?did different people map them? Who drove them?
 
also has one lasted longer than the other?
 
 
 
this isn\'t an attack btw, genuinely interested

The FD\'s are mine (RICESP) *general details of my car and some specs etc*  http://www.aquamist.co.uk/vbulletin/showthread.php?t=1590 and the other is here > http://www.rx7club.com/showthread.php?t=631485&page=5 (both meet std\'s for tuning, build, evidence of performance *video proof and VBOX3i*).
 
Generally speaking its a little known fact that stock standard porting is by far and away the most responsive and able to spool up a BIG turbocharger, especially v\'s "street ported" engines. And even bridge ported engines as well........
 
For durability I have a hand full of customers who still after 8 years (I know time is meaningless) or around 50,000km still run the same stock standard engine (across S5 to 13B-REW) at genuine 500bhp power level (around 440rwhp dynodynamics). Life span is great, power band is unmatched and most importantly the tollerance to running in street trim is high. Hope this is of some help to people who are interested?
 
I love my street ports, I do more of these than anything else, but there is very big negatives to running them as an overal concept in a road or track car. I personally in my own ride swapped from 3 different iterations of intake and exhaust porting to find the best balance on a T04Z matched to Mazda gearbox and the best I have foud is the stock standard porting. Though I do love the peak figures you can get from street ports (all other variables being held constant) its hard to beat a stock port (S5 to 13B-REW) motor in reality. Can provide as many samples across all kinds of fields but I dont want to bore you or come across as a know it all :WaveBye
 
Between 4k to 8k rpm stock port is a great set up *pick whatever power level you want to have* street car, circuit car, or 140+mph 9 second drag car.

[PGiljevic]

Hi Pete,
 
Good to see you on these boards
 
RR SP or go home lol.

Thanks :wave
 
Here is more direct link showing power bands of my own testing http://www.aquamist.co.uk/vbulletin/showthread.php?t=1590&page=8
Full road set up with quiet exhaust and full catalyst, you can run this car and breath the air out the tail pipe :InLove T04Z 1.00A/R set up as in pic\'s.
 
I put alot of focus into genuine honest power and bredth of it that is available. many cars (competition gutted RX7\'s with full bridge ports and reputed 400rwkw *dynodynamics* engines) can only just match the terminal speed at the end of a main straight where you can reach ~235kmh, make of that what you will............... (VBOX proof of both).
 
I am doing some small upgrades to the turbocharger this week and will share up a graph of power and performance over a typical 400m test run on 1.5bar or around 22psi again in full proper street trim. Not everyone cup of tea but interesting to some I suppose :mmmm

[HaywardRotary]

You can get a good combination by porting the secondary inlets only and the exhaust ports too.
what porting does is enable the same amount of airflow with lower boost,but effectively the CFM is the same with lower temps due to the lower boost pressure.
Duration is kep to good porting in these circumstances.
Basically it comes down to 2 things to acheive a similar result,more boost on stock ports or less boost on a ported engine with both running the same volume of air to make same power.
Regards
Carl

[PGiljevic]

Hello Carl :Ladys-man

Yes the arguments are many and varied :3gears-lh

I have found over the years (as you have and many others in this game) that indeed the power (at peak) goes up, how much and what you loose along the way is the important bit.

:2Confused You (all of us) need to look at good power curves 3rd gear acceleration is a good started and see how the power is mapped in a transient environment like real acceleration to get the full picture (it gets inflated in lower gears or on/off throttle situations, and has less effect in top gear *slower rpm change rate*).

This is the secret to all of this talk about porting.

For a flat boost curve I am yet to see any ports that make better spread of power than stock std (S5 to 13B-REW) port timing, sure the others will deliver higher power due to the simple fact of ~500rpm higher peak speed of the engine, but they loose out everywhere else, and they do not spool as good at stock, they are more effected by post turbine pressure, and or running turbo\'s with higher expansion ratio\'s as well........ the list of negatives is long and diverse.

Weighed against that is that you only need to *worst case* run ~3 psi more boost (at around 20psi level) to match the peak power of the ported engine, BUT you have a literal mountain more at any rev\'s below the peak and this is the secret to why std ported engines are so quick when tuned properly and set up well.

I will post up a classic std port power curve to illustrate my point (puts 20B\'s to shame!)

After 60,000km the water seal started to weep & The owner wanted the same power on lower boost, hence i street ported it. Is it necessary? (me answering as an engine builder and tuner) *100% not necessary at all*

320rwkw @ 17.5psi (RR street porting)

V\'s

320rwkw @ ~21psi (for a stock engine)  

http://www.ausrotary.com/viewtopic.php?f=19&t=69871  (did actually run 325rwkw) 3 consecutive club dyno days, see detail in this above thread.
http://www.ausrotary.com/viewtopic.php?f=5&t=42769&start=180 user name pp13b *he lives in UK now hi Tom !

Video of car with stock motor >  http://www.riceracing.com.au/Videos/440_bHp_Series_2_water-injection.wmv

[shaunwil]

Probably the best advice to give is what I ended up doing. I\'ve run a single for a couple of years and now the engine has died I\'m having it ported at the same time as the refresh (cracked an apex seal and had a slight water leak). Not looking for anything too silly, just want it to pick it feet up on boost earlier (used for track days) coming out of corners.

The cost of porting the engine isn\'t too crazy then because it is done whilst the engine needs to be in bits.

Shaun

[Mir]

After reading this post and researching along side..I tend to agree with Rice Racing however, there are very convincing arguments on both sides.
Regards

[DR SCHNITZEL]

so ive wasted my money and time? i wanted a faster car on the track and have gone for a medium port. will i not be as good out of the corners? I was under the impression my peak power will be lower down the revs and my peak power will be 50hp more than on stock ports. i have a small hotside to hopefully get on full boost quickly. hmmmmm. i did like stock ports on my to4r .81

[PGiljevic]

100% not needed ! for that power level or considerably higher.
 
Here is proof why >
 
Further to this post (stock V\'s street port)
 
Two RX7\'s both weight checked prior to running, both dyno\'s *varying methods* alone with vastly varying estimates of engine power! one matches reality (read other cars) the other is optimistic to say the least!
 
Stripped track car (13B-REW street port) Garrett single turbo 1.3bar
1> 1180kg (432rwhp DD! owners dyno shop estimates 509bhp!!!!!!!)
100kmh-200kmh = 8.3 seconds
 
Road car (13B-REW stock) Garrett single turbo 1.3bar
2> 1380kg (275rwkw "real power measure!" owner estimates honest 430bhp in this test)
100kmh-200kmh = 8.2 seconds
 
(same number of gearshifts, same OEM gearbox, same shift points.........) *both at sea level and std temp and pressure day* You do the maths power curve on one is far superior, but also some dyno figures are not worth the paper they are printed on
 
I do all kinds of porting from street port to peripheral and across more than I care to remember over years can honestly tell you that porting is 100% not necessary on any kind of road going 13B-REW *regardless of turbo size 400bhp to 800bhp* (and some track cars!) infact its actually a big backwards step in terms of speed (not just a token power print out of the peak "blip")

 
RICESP 100kmh - 200kmh even faster now on stock ports
 
7.53 seconds. :Thumbsup!  http://www.youtube.com/watch?v=OqvaMTJZn8k&feature=player_embedded
 
So is porting necessary? I think not :spank

[PGiljevic]

so ive wasted my money and time? i wanted a faster car on the track and have gone for a medium port. will i not be as good out of the corners? I was under the impression my peak power will be lower down the revs and my peak power will be 50hp more than on stock ports. i have a small hotside to hopefully get on full boost quickly. hmmmmm. i did like stock ports on my to4r .81

I\'ll *time permiting* post up why its a negative thing to port a road car.
When you analyse my own power curve to make the most of the power band (remember stock ports) you need to rev the car to 8400rpm to 8500rpm, and in lower gears like 1st and 2nd as high as 8800rpm! You can\'t check this by looking at a dyno sheet and making a guess, if you run it through a computer program that analysis your power an tq curve properly you will see that this is how high you need to rev to get minimum times and maximum average acceleration on the std mazda gearbox!
 
I have had "arguments" with people who race Mazda\'s professionally over this :2Confused regardless to say they dont make cars as powerful or perform over a measured time increment anything near RICESP, but they have mega opinions on what is best back up by nothing more than hot wind, no proper power curves to engine rpm, no proper measurement, no analysis, nothing.
 
When you check all this properly you see even more why it is totally pointless to port a standard 13B-REW. The only time you could ever use it is if you have a close ratio gearbox and something fitted with dog rings rather than syncronizers to greatly reduce shift time loss, and preferably a 6 speed to make up for the loss of range of bringing the ratio\'s closer together.
 
It is best to keep the engine drivable, to let it have a wider range of power, much more mid range power and use the turbo to increase this mid range........ porting and lower boost is not the way to do this at all. As I have proved above. :driving
 
:Hammer

[PGiljevic]

After reading this post and researching along side..I tend to agree with Rice Racing however, there are very convincing arguments on both sides.
Regards

People can "argue" and post all they want (not saying you are) but at the end of the day all that matters is facts and legitimate results (that can be easily compared).
 
Weigh the car
Measure the power
Show us how fast it accelerates from 100kmh to 200kmh
 
^ You will see which car has the best power band and power to reach that basic speed in a respectable time. Anyone can do it, and discounting people who dont have proper insturments or want to cheat themselves you will see what is best in the real world V\'s dyno sheet/claim world. Best thing is you can compare it to so many other cars as well and see how you stack up, with no excuses for poor traction, bad shifting (like in drug racing), and it eliminates *optimistic dyno sheets* especially when you are looking at similar vehicles. The bull.... stops when the clock starts.