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-   -   EP Road Racing and the 89+ Intake (https://www.rx7club.com/race-car-tech-103/ep-road-racing-89-intake-313098/)

SPiN Racing 06-02-04 10:28 PM

EP Road Racing and the 89+ Intake
 
I am putting together my EP 2nd Gen, and have a interesting question regarding intakes...

I have many of the 86-88 Vintage intakes, and have done some healthy porting to them, as well as a LOT of mods to them... within reason...And get good results from them.

I realise in Stock trim.. the 89+ Intake is the preferred intake for IT and SS racing.. along with the stock based classes for AutoXing...

SOOOO.... If you are allowed to port the snot out of the intake.. like you are in EP.. including removal of the 6-port sleeves, and the VDI.....

Which intake will make more power in a unlimited arena like EP..

Now granted you have to keep the Throttle body stock.. BUT.. you can clean up the intake itself a LOT.. and port match etc.. as well as cut it apart to clean up all the runners etc.. and re-weld it back together.. (It is done a LOT in the EP GSLSE manifolds.. the re-welding that is)

Any ideas which one will build more power? Should I work the VDI into the equation with the EFI I am running??

I WISH I could just throw a down draft 2 Barrel IDA TWM Throttle body on it and be done LOL

Thanks for the input.. all

(I did ask on the Prod forums.. but no response yet)

PS: I do have both manifolds.. so I may end up having to try em both out on the dyno and see what I get.. /groan :D

tims 06-05-04 12:43 AM

I am using the '91 intake for my motor. top fuel injected engines use the later manifold. I have no experience with the later manifolds.

cpa7man 06-07-04 06:37 PM

Hey, I don't mean to threadjack here but can you give me the link to the production forums?:)

I'm trying to decide if its worth it to build a 1st gen e-prod car. Since I have 2 rollers that's the path of least resistance.:)

EProdRx7 06-08-04 06:52 AM

Here's the link to the prod site http://www.coloradoscca.org/prodcar/index.php
BTW my car is for sale :)

SPiN Racing 06-08-04 08:02 PM

He he Beat me to it :D

Do you have any links etc on the car for sale??

TNH 06-08-04 08:12 PM

How about for a drag car that see's little street use. I'm thinking of welding mine up

Bern 06-09-04 05:18 PM

Guys:
There are many technical problems with using the stock manifolds in E-Prod; the biggest being the runner length and the very thin castings. This limits the amount of porting that can be done to the OEM pieces. The manifolds are very uneven and restrictive in certain areas and they can not be matched to the larger diameters because of the thin castings. Also, the VDI and/or removal of also presents somewhat of a problem with reversion and control of the pulse and where in the rev range it works. In OEM applications the VDI is programmed at a reasonable level and tuned very nicely for street use, but in a race engine that's regulary seeing 8500-10000rpm, it's a different story.

IMHO, these difficulties have still not been overcome enough to make the OEM manifold work better or even close to, the umlimited carb manifolds allowed in E-Prod.

-Bern

Bern 06-09-04 05:19 PM


Originally posted by TNH
How about for a drag car that see's little street use. I'm thinking of welding mine up
If your in a open class and are not running to any rules, I'd say go with aftermarket throttle-bodies and injection. No need to keep the stock manifold.

-Bern

SPiN Racing 06-09-04 05:43 PM

I am with you on the facts about the amounts of power available from a downdraft with a unlimited carb manifold..
I myself would just slap one on.. but at this point I really dont like tuning carbs.. I much prefer the FI applications.
On the GSLSE engines I installed and tuned a setup on a persons EP race car.. a former National Champ prepping his car for the runoffs.. and he was making much more power with the stand alone system than he had in the past. He broke 3rd gear at the end of testing.. and had to cut it short.. but he was very impressed with the performance he got from it.

Another key point in the FI.. is the fact that this engine is the base engine.. NOT the shoot to kill motor. I am making this one the reliable no-fail motor. The shoot to kill will hurt the wallet a bit more.. as it will have the more expensive pieces approaching the limits of the class. (IE Lightened a LOT rotors etc.)

IF I am soo far down on power that it isnt compettitive.. I will then look into the other options such as a carb :puke:

Bern 06-09-04 06:28 PM


Originally posted by SPiN Racing
I am with you on the facts about the amounts of power available from a downdraft with a unlimited carb manifold..
I myself would just slap one on.. but at this point I really dont like tuning carbs.. I much prefer the FI applications.
On the GSLSE engines I installed and tuned a setup on a persons EP race car.. a former National Champ prepping his car for the runoffs.. and he was making much more power with the stand alone system than he had in the past. He broke 3rd gear at the end of testing.. and had to cut it short.. but he was very impressed with the performance he got from it.

Another key point in the FI.. is the fact that this engine is the base engine.. NOT the shoot to kill motor. I am making this one the reliable no-fail motor. The shoot to kill will hurt the wallet a bit more.. as it will have the more expensive pieces approaching the limits of the class. (IE Lightened a LOT rotors etc.)

IF I am soo far down on power that it isnt compettitive.. I will then look into the other options such as a carb :puke:

With this information, then I would have to say that a re-worked stock manifold, and your FI, would be a nice set-up. My statement was geared toward what you call the "shoot to kill" full-on national championship motors. I too like working with FI and recognize it's adavantages, but in a full-tilt EP motor, the OEM manifold, to date, seems to be the major obstacle to power.

And oh yea... a top killer motor will definitely hurt the wallet!!! ;)

-Bern

Bern 06-09-04 06:30 PM


Originally posted by SPiN Racing
IF I am soo far down on power that it isnt compettitive.. I will then look into the other options such as a carb :puke:
Are you looking at a National program... Run-Offs?

-Bern

tims 06-09-04 07:17 PM

Bern you have it nailed. the runner length is way to long especially when compared to what you can run with a carb, and the VDI still has me wondering which direction is best. I haven't had a chance to dyno my current setup, but it has good power everywhere but right around 5000-5500 rpm. this maybe the area the stock system switches, but I am not sure. a couple friends with FI 13b's have reported the same anomally at 5000 rpm's. I may scrap the oem manifold until I want to sell the car.

Bern 06-09-04 08:31 PM


Originally posted by tims
Bern you have it nailed. the runner length is way to long especially when compared to what you can run with a carb, and the VDI still has me wondering which direction is best. I haven't had a chance to dyno my current setup, but it has good power everywhere but right around 5000-5500 rpm. this maybe the area the stock system switches, but I am not sure. a couple friends with FI 13b's have reported the same anomally at 5000 rpm's. I may scrap the oem manifold until I want to sell the car.
Tims,
The 5000-5500 rpm range is close to the stock swith-over, so this might be it. But, one shouldn't even worry that much about power at this low RPM in a E-Prod motor. Things really don't start kicking 'til after 6000 rpm.. from there it's up to whatever you dare or paid for ;)

-Bern

SPiN Racing 06-09-04 11:40 PM

bah double post.

SPiN Racing 06-09-04 11:40 PM


Originally posted by Bern
Are you looking at a National program... Run-Offs?

-Bern

At this point with this car I am just getting together and on the track with a stable motor. I want to get it together before the season is over and get some races on it while building the fun motor.
I am not sure I am at the caliber to go to the runoff level. Everyone would like to think so.. but I have watched Mike VanSteenberg run.. and... well.. he is an amazing racer.. he is very fast. To make a understatement.
I dont think I am at that point. I am sure I am not... But how fast I can ramp up is another question.
I also work at a large corporation that has expressed interest in sponsorship... BUT... I need to get the program running and stable before the bank will show up... IF I can get it together to get it reliably on the track doing well.. I may be able to get enough "help" to go for a program. I am not forseeing it this year.. but we will see for next year's season.
Course like it is for most of us.. the Finances limit the speed at which you can throw the car together.. to get it on the track.
Program... have it all mapped out for the hardware side of things.. Now to just get the car on the track and start clocking the time, to pitch the program.... to be able to afford to be more serious about the national effort.

EProdRx7 06-10-04 06:42 AM


And oh yea... a top killer motor will definitely hurt the wallet!!!
I'm feeling it man...:mad:

In the discussion of FI over the carb I have to put my money on the FI. Ultimate max power potential is better on the Carb but the power band with the FI is much more useable. Torque is what wins races...

Tims, unless you can activate the valve electronically with some sort of a RPM activated switch just wire it open and forget about it.

Sebbiebaby 06-10-04 03:52 PM


Originally posted by EProdRx7
I'm feeling it man...:mad:

In the discussion of FI over the carb I have to put my money on the FI. Ultimate max power potential is better on the Carb but the power band with the FI is much more useable. Torque is what wins races...

Tims, unless you can activate the valve electronically with some sort of a RPM activated switch just wire it open and forget about it.

I know what you mean on motors... good for me that's not my money being spent :)

E-ProdRx7, I really respect your opinion, as you are one of the guys really developing the FI and OEM manifold, but this is not really a discussion of FI vs. Carb... it's
really about the virtues and the potential of the modified OEM manifold vs. the unlimited carb manifold set up within the current E-PROD arena and rules. I'm in total agreement that FI can make a more usable power-band, but without us all sharing dyno sheets with HP & TQ#'s here, about this very specific set up, it's difficult to show just how big of a powerband/TQ advantage the FI with a OEM manifold vs. the carb and unlimited manifold has in E-Prod. Btw, the carb is not really loosing that much to the FI in useable power-band.

When one sees the benchflow #'s for both manifold set-ups, it understandable as to the reasons discussed here. The more air one can stuff into the motor, the more power. The TB has great potential on the FI set up, but the manifold is still letting it down.

Believe you me though, that in my camp, FI is still being studied hard. There are many technical difficulties with FI on the 2nd gen E-Prod motor, but this doesn't mean that it is impossible to overcome... it's only time and MONEY, right? ;)

Btw, great discussion guys!

-Bern

Rx7carl 06-10-04 07:34 PM

Scott, if you want to pursue this avenue I do have a flowbench here. I could run some tests for ya.

Bern 06-10-04 08:06 PM


Originally posted by Rx7carl
Scott, if you want to pursue this avenue I do have a flowbench here. I could run some tests for ya.
Hey Carl, what kind of flow bench do you use?

-Bern

SPiN Racing 06-11-04 11:47 PM


Originally posted by Rx7carl
Scott, if you want to pursue this avenue I do have a flowbench here. I could run some tests for ya.
OH MAN i FORGOT!!
OK I will DEFINATELY give you a jingle.. I will get both manifolds all ported up and then we can bolt em down and see who breathes better :D

Then we will all know :)

I will let ya know soon as I get them done..

Right now.. I am going back out to start getting my Exhaust ports done ;) The Devcon is drying in the 6-port areas... cause I dont like the contours in there where the sleeves used to be :puke:

The New re-shaped contours should be Muuuuch nicer :rock:

If there is interest I will post some pics after the engine goes together.. or..... not.. if it makes real power ROFL

Bern 06-12-04 01:51 AM


Originally posted by SPiN Racing
OH MAN i FORGOT!!
OK I will DEFINATELY give you a jingle.. I will get both manifolds all ported up and then we can bolt em down and see who breathes better :D

Then we will all know :)

I will let ya know soon as I get them done..

Make sure your using a quality IDA manifold not a Racing Beat LONG runner type piece. The medium to shortie work best. There is a big diference between the manifolds out there. Let alone the matching work between the manifolds and motor ports.

Also, critical beyond the mani, is to have a good modified Weber or Berg carb. Lots of secrets here boys. ;)



Originally posted by SPiN Racing
Right now.. I am going back out to start getting my Exhaust ports done ;) The Devcon is drying in the 6-port areas... cause I dont like the contours in there where the sleeves used to be :puke:

The New re-shaped contours should be Muuuuch nicer :rock:[/B]
Be careful, if I remember correctly, you are not allowed to ADD material here.


Originally posted by SPiN Racing
If there is interest I will post some pics after the engine goes together.. or..... not.. if it makes real power ROFL [/B]
I'd love to see them!

-Bern

Rx7carl 06-12-04 10:17 AM


Originally posted by Bern
Hey Carl, what kind of flow bench do you use?

-Bern

The one I built. :D Its an orifice style with 8 different orifices for flowing different size objects.

Rx7carl 06-12-04 10:19 AM


Originally posted by SPiN Racing
OH MAN i FORGOT!!
OK I will DEFINATELY give you a jingle.. I will get both manifolds all ported up and then we can bolt em down and see who breathes better :D

Then we will all know :)

I will let ya know soon as I get them done..

Right now.. I am going back out to start getting my Exhaust ports done ;) The Devcon is drying in the 6-port areas... cause I dont like the contours in there where the sleeves used to be :puke:

The New re-shaped contours should be Muuuuch nicer :rock:

If there is interest I will post some pics after the engine goes together.. or..... not.. if it makes real power ROFL

Sure, just hit me up when your done. BTW Bern might be right about adding material in the 6 port area. Would it be legal to replace the sleeves with a pineapple style sleeve?

SPiN Racing 06-12-04 03:02 PM

Dunno about the sleeves.. but just got the word from a couple of the EP top runners.. No using Devcon in the 6-ports.

We are stuck with the nasty wall at the end of the runners. :puke:

BUT.. if the top runners can make nice power with it that way.. I will work to do the same :D

Rx7carl 06-13-04 09:46 AM

Hey, can you send me a LIM to borrow? I need one as a guide/template to make an adapter so I can bolt your intake to the flowbench when your ready to test.


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