How much HP's expected from Street ports
 

How much Horse power can one expect from a Street port in a 6 port engine? I want to race a 2nd Gen in RS in SCCA and would be required to run a 6 port. How much can be expected with a Motec or similar fuel injection?

Anybody have any Dyno specs?

This is listed else where also. Really need some realistic HP quotes.

Thanks!

Expect some 200-210 flywheel horsepower, I streetported a sixer for my old FC.
http://64.9.213.132/rx7club.com/foru...d.php?t=349280

It had the stock mufflers, which ate quite some hp:( but it was nice and quiet

181 hp @ wheels on my ported 6 port with 89 rotors

how much would it be to street port it?

go to Mazdatrix.com or Racingbeat.com and check their prices. IIRC it's like $700. But if you order the templates and do it yourself it will be much much cheaper, and before you ask how to port, search. There are millions of threads about it.

Ron

street ported 6 port
 

I personally know of a E prod car in so california. That has a modifyed LARGE street port. and a modifyed S4 Intake that is making 280 + to the flywheel. It has been recently " de tuned" for drivability. But this has taken numerous hours of flow bench testing, burnt up stationary gears,and spent bearings. Probably 6 motors worth. So far, the ceramic seals have not failed though. So it is like the old adage How much HP you require depends on how deep your pockets are. I would think 200-220 would be reasonable on a budget.

I'd like to see the dyno sheet on that car before I believe it. PPorts are usually in the 280+ range. a NA SP will never make that much with 13b or 12A. Feel free to prove me wrong though.

Ron

Ponys maybe, but not horses! :rlaugh:
Bill Gates' personal budget could not make an E-prod motor make those #'s

Is that 200 hp range using stock injectors and no mods to the stock manifold & FI electronics?
I was told by JLC Racing in Kent that the most I could expect from a port job on my pure stock 85 SE was 15% because the stock FI and induction couldn't support much more flow that the porting would give. So, assuming about 135 hp for stock plus 15% would give me around 155 hp.

I am scheduled to run my street ported 13b 6 port next wednesday(3/16/05). this is the second run(first was with broken side seals) on the dyno for this engine. I feel the 200hp at the rear wheels is very possible and I would like 225hp. I have heard rumours that some of the e production guys have gotten as high as 250hp at the wheels. If all goes well I'll post the results. the first run with the blown side seals resulted in exactly 100hp and that was with 3 of the rotor faces with 0 compression or basicly half and engine.

Another "gonna do" who never did! Why post what you're gonna do without showing what you "did". I call bullshit bullshit bullshit. Actually I'd like to call bullshit on 98% of all the gonna do'ers!

I'll update everyone. I did not make the dyno test. The engine decided to act up the weekend before the test. I fixed the small problem with the ignition and I am scheduled to test again this coming friday,3/25/05. You don't have to worry about me not doing something. I will be at the dyno this friday. I may not rush home to my computer to fill you in, but I'll be there. I have run this car twice on a chassis dyno and each time there have been problems with the engine, so no need to post any results. Last time with two blown side seals it made 100HP at the wheels. The E-production guys running carbs are making 250HP to the rear wheels easily. unfortunately the EFI engine can only use the OEM intake manifold and throttle body. the carb engines can use any manifold and are allowed 44 or 48mm chokes(I can't remember which) this is very large and the shorter manifold they use is much better than the OEM intake. if the EFI engine could use a shorter custom manifold they could easily make the same HP number.

show me a EP car making 250 RWHP and I will show you a non-legal motor. We can only run up to 38MM chokes BTW

I don't know about a 13b, but I do know that a 12a is capable of 230-240hp on the engine dyno. According to my sources :) this range is about all that can be had, ceramic seals and a large street port. Most using Weber IDA's fully flow tested, ported/polished intake manifolds with the best exhaust made.

If anyone is making 250 rwhp, let me in on your secrets.;)

Double post

OK - I run an EP 12a and I have heard recent dyno rear wheel numbers from a competitor who runs a national quality 13b and I can tell you that you are WAY off base. There is NO ONE running a legal EP rotary that is getting anything like 250 rear wheel horsepower. This sound a lot like one of those "I heard from my buddy's cousin that you can get 300 hp with one of those new cyclone intake" kind of stories. Believe me, you're not close.

***show me a EP car making 250 RWHP***

Show me also please.......... & being legal is required................

Have Fun ;)
David

As for legal that is always a question. I do know that more than one of the engines were run at the runoffs and went through the tech and inspection. I realise this does not guarantee it is legal but it was raced. I have heard the HP numbers from more than one competitor and they were all first hand accounts. They could have also been stretching the truth a bit also but they have all been very successful with their setups too. If my test is successful(engine survives) I'll post my results. And for sure my engine would be absolutely legal. In fact it is very tame compared to others. No ceramic seals or trick lightened(sp?) rotors.

this oughta be good... although would be encouraging if theres the slightest bit of truth to these claims.

I saw one of pablo's early reasonably budgeted EP motor's with 48 dcoe and the bigger chokes (2 years ago?) put 188 to the ground. Starting this year EP 13b's can only use 38mm chokes and they're down on power.

Take a look at the EP trap speeds from this years runnoffs. I know Trash is legal. He had trap speeds of 130. I don't know Neal and I'm not sure if he was running a 12a or 13b, but he was the fastest 1st gen with a trap speed of 133. Who is the guy with 250 rwhp?


http://www.scca.org/_Filelibrary/Fil...n-traps-ep.pdf

Bob Neal is a good friend of Dave Lemon from Mazdatrix and is a very good driver. I believe he is running a 13b. Did they reduce the choke size recently for the carb engines? I said before I don't keep up on all the rule changes. These numbers were stated after the SCCA had increased the choke size for the carb engines. If they have since reduced the choke then HP levels are likely lower. I was putting my engine together early 2004 so things have likely changed since then. The one FI engine builder was still claiming similair numbers but they could not get it to last the whole race and the driver was not as talented as some of the other regulars so it never showed during the race. I have seen the lap times at some of our local tracks start to come down recently so something is happening.

As stated above 38mm chokes/venturies are allowed for 12a/13b. Same rule since 2003. Well for sure no one is going to give up their go fast secrets. I know the 13b will out power the 12a, but with the 140lb weight penalty plus more engine weight, larger rotating mass, more frequent rebuilds my $$ are on the 12a in EP.

A correction to my last post.....Trash should have read Thrash as in Tom Thrash.....sorry Tom.

Most have said that the Carbs are only getting about 210hp at the rear wheels. Now the EFi guys should be getting about 225-235 at the rear wheels. I know of 2 EFI motors that have reached those figures and have not blowen-up. Yes they have probably spent about the same on those engines as most people would have spent on there entire race cars.

We all have to remember though, that what one engine dyno readings say don't mean the same on the other side ofthe US. I also no that some figures have been based on Engine Dyno's then calculating the horsepower loss thru the drive train. You have to compare the same set-up. (i.e. same weight flywheel, same clutch unit, same transmission gears and rear end ratios. Also needs to be tested in 4th gear. Some dyno operators run cars in third gear to get it to spin up faster.)

your right about the dyno numbers and also some dyno shops will use corrected HP numbers. the dyno will correct the HP numbers based on the ambient air temp and other things. That is why I do all pulls in the gear which is 1:1(4th on my current gearbox) and I don't use an correction factors. I also like to use the same dyno but this has been a problem. I have yet to use a shop that when I left I felt they knew more about the dyno than I did. Seems like alot of shops have bought the equipment but never learned how to operate it properly. The latest shop comes highly recommended and has a good track record, so we will see. I will give all details after I have finished the testing and tuning.

c'mon tims it's friday, I'm waiting for these astounding numbers :D

I knew you guys would be waiting to pounce. the dyno day was a success. the engine runs great and it is running slightly rich for some personal comfort. One thing the dyno proved is that the throttle body and intake are a sizable restriction. the engine was still in a vaccum at 8000 rpm. Best max HP I could get was 190HP to the rear wheels at about 7500rpm. final setup is 180HP at about the same rpm. Not what I was hoping for but the engine runs clean and smooth. Starts and idles well also. I had never promised any wild numbers for my engine. I was reporting stories and tall tales I had heard(these now sound like out right lies). It looks like the EP regulars know their stuff. My engine would be absolutely legal for EP and with some legal work to the throttle body you could get a little more air and HP. But I don't think you could get another 50-80HP without some serious modifications to the intake and TB that would likely not be legal. I will post the complete dyno sheet tommorrow(I forgot it in the truck). Man what a long day/night.

they don't call us the forum "smart" asses for nothing :D not bad numbers at all though. We are hoping to get around that same number, if so we'll be in good shape. Just for fun when we get on the dyno we'll post the slip too. What dyno was it on do you know? we'll be on a AWD mustang dyno, which supposedly likes to read less optimistic than others. Either way 180-190 is good on an NA congrats man.

Ron

Agreed.;) Good job Tim. I'll post up my details as well. I'm buying an EP motor from Tom Thrash with his port. I'm tearing down my other motor to see why I blew a rear rotor apex seal (again). I'm still a month out, but I'll post up when available.

Paul

The Dyno was a Supeflow, not sure which model. It had a few options that previous dynos I have used did not have that made tuning much easier. The guys at Westech Performance (http://www.westechperformance.com/) did a great job. Tom was by far and away the best dyno operator/tuner I have used. He did all the work. All I did was "drive" the car on the dyno and follow his orders. Specs for my engine are OEM intake and throttle body from a '91 RX7, turboII injectors, variable intake "drum" removed, AWR header(longer than would be optimal), straight through exhaust, home made "cold air" intake and K&N type cone filter, and all controlled by a Haltech E6K.

Image of HP curve. sorry for poor quality scan.

Tims, What did you replace VDI Drum with.

Nice powerband!

I just removed the drum all together and plated off the large hole. I did some experimentation early on and could not tell a difference(not on the dyno), so I just removed it. I seems to run great and the powerband is nice and flat.

Actually, it hurts horsepower. The Air as it comes down the tubes hits the large chamber and creates a masive amount of turbulance. The air does not no which why to go. You should fine and inmrpovement in horsepower and torque if you put it back in and Wire the VDI open.

Your horsepower figures are still two low for and Basic EP motor with EFI. You should be about 200hp at the rear wheels, without having the intake manifold modified

which passages are considered the "open" position.

The Plastic valves holes should line up with the cross holes in the intake manifold. What that does is shortens runners in the intake manifold which gives you more horsepower in the upper rpm but less torque.

If you had left the valve in their then closed it so the holes in the intake manifold where closed it would make the runners longer which would give you more torque in the lower rpm and less hp.

You should find that you were down about 15 to 20 hp on your dyno test.

As I recall (been a while since I looked at it) there are two seperate passages and depending on how the drum is turned one or the other passages are open to the main "plenum". so which section should be open to the main? I don't know how the stock setup works. I have never seen any of this stuff operate on a regular road car, so I don't understand which section should be open/closed. I have raced this car for a while but I have never even driven or worked on a stock RX7 of any kind.

Actually Tim, both passages are open at the same time, when the valve is turned the correct way. The passages are straight across from each other. You trun the valve so it connects the passages on one side of the tube to the other. I would be interested in what you find on the horsepower when you re dyno it with this changed. I have been looking into changing my ITS car into and RS car which I can install a Haltech System. I am real interested in what you can get out of it.

I have to look at that drum again. I remember looking at it and trying to visually see which direction would be best. I ran the engine without the current tuning and saw no change in either orientation. I ask around a bit and I had heard of people just removing it, so this is how I started. I'll look at it this weekend and see if I can figure it out.

I finally got to the shop to look at the intake drum. I set it to have the holes in the drum running paralle to the ground connecting to two runners side to side. I'll see if it makes any changes this weekend.