Rotaryman88's Staged NA upgrades...
06-22-2002, 11:51 AM
#1
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Well, I get a lot of questions from new Rx7 owners w/ the '86 to '91 NAs. Instead of repeating myself all the time, I'm making a post of what I think the best setup is for NA guys w/ stock motors and can't afford the rebuild thing right now.
STAGE ONE: EXHAUST
Exhaust, in my opinion should be done first. Many people will get the intake first becuase its cheaper, but my belief is the motor needs to rid itself of the exhaust gases it already produces before worrying about getting more air in. It's also a good idea, in my opinion, to start from the mufflers forward.
1. Start w/ a hi-flo catback system. It's good for about 5hp and can get you the more agressive exhaust note you'd want. As for company's..obviously Racing Beat is the best for you NA guys who wanna stay quieter but still get the performance. Racing Beat is a little pricey though. As a cheaper alternative, I'd recommend ww.rx7.com's own RP 50mm catback. It's cheap and offers about the same gains as racing beat's system on a stock motor.
2. Next, get the hi-flo cat. If you want to pass your visual inspection, you'll need at least one cat. Both Mindtrain and Bonez are good choices. If inspection is not your worry, then stop by your local exhaust shop and have them make a "TEST" pipe to fit between the stock precats and the catback...its your cheapest bet.
3. Finally, set the car up with some nice headers. You may want to check with your local emissions laws to be sure if the headers will pass, but you should be ok in most places. The headers will give you about another 10 to 12 HP on a stock port, which isn't bad at all. Again, Racing Beat is a good way to go, but cheaper yet is Pacesetter..whom I'm not really fond of, but hey, its cheap.
Stage one will gain you about 15 to 20 HP on a stock motor and provided you don't get a large diameter catback and keep the hi-flo cat, you shouldn't worry about the 6th port actuators, I ran straight pipe w/ the stock catback and I didn't have a problem.
STAGE TWO: INTAKE
Now that you have the car flowing good with the exhaust, you should try to get more air into the mixture.
1. Obviously, everybody's first choice is to get the cone filter. Its good for about 2 to 3 HP and cleans the engine bay up a bit. You '86 to '88 guys will need to purchase the adapter for the AFM, but the '89+ guys can just get the filter and strap it on.
2. Next, build a cold air box around the filter. Using thinner aluminum or the metal of your choice, build a shield between the hot radiator hose and the filter. It's also a good idea to block out the heat from the motor itself(so a full box minus the top is the best bet). This will get about another 1 to 2 HP. For every 11 degrees colder the intake air temp is, you gain 1HP.
3. If you get really creative, your next bet is to relocate the filter out of the engine bay and down in front of the radiator. This will take some crafty piping and a little more $$, but I've seen a gain of 7RWHP on an '86 Rx7 with this kind of setup.
4. Next you can perform the TB mod. It's more popular for the '89+ guys and T2 guys, but it still works on all 2nd gens. I'm not going into to detail about this, but check the FAQs page or ask around, many people know about it. It's good for throttle response, and maybe another 1 to 2HP.
More stages when I get back from break, lol....
STAGE ONE: EXHAUST
Exhaust, in my opinion should be done first. Many people will get the intake first becuase its cheaper, but my belief is the motor needs to rid itself of the exhaust gases it already produces before worrying about getting more air in. It's also a good idea, in my opinion, to start from the mufflers forward.
1. Start w/ a hi-flo catback system. It's good for about 5hp and can get you the more agressive exhaust note you'd want. As for company's..obviously Racing Beat is the best for you NA guys who wanna stay quieter but still get the performance. Racing Beat is a little pricey though. As a cheaper alternative, I'd recommend ww.rx7.com's own RP 50mm catback. It's cheap and offers about the same gains as racing beat's system on a stock motor.
2. Next, get the hi-flo cat. If you want to pass your visual inspection, you'll need at least one cat. Both Mindtrain and Bonez are good choices. If inspection is not your worry, then stop by your local exhaust shop and have them make a "TEST" pipe to fit between the stock precats and the catback...its your cheapest bet.
3. Finally, set the car up with some nice headers. You may want to check with your local emissions laws to be sure if the headers will pass, but you should be ok in most places. The headers will give you about another 10 to 12 HP on a stock port, which isn't bad at all. Again, Racing Beat is a good way to go, but cheaper yet is Pacesetter..whom I'm not really fond of, but hey, its cheap.
Stage one will gain you about 15 to 20 HP on a stock motor and provided you don't get a large diameter catback and keep the hi-flo cat, you shouldn't worry about the 6th port actuators, I ran straight pipe w/ the stock catback and I didn't have a problem.
STAGE TWO: INTAKE
Now that you have the car flowing good with the exhaust, you should try to get more air into the mixture.
1. Obviously, everybody's first choice is to get the cone filter. Its good for about 2 to 3 HP and cleans the engine bay up a bit. You '86 to '88 guys will need to purchase the adapter for the AFM, but the '89+ guys can just get the filter and strap it on.
2. Next, build a cold air box around the filter. Using thinner aluminum or the metal of your choice, build a shield between the hot radiator hose and the filter. It's also a good idea to block out the heat from the motor itself(so a full box minus the top is the best bet). This will get about another 1 to 2 HP. For every 11 degrees colder the intake air temp is, you gain 1HP.
3. If you get really creative, your next bet is to relocate the filter out of the engine bay and down in front of the radiator. This will take some crafty piping and a little more $$, but I've seen a gain of 7RWHP on an '86 Rx7 with this kind of setup.
4. Next you can perform the TB mod. It's more popular for the '89+ guys and T2 guys, but it still works on all 2nd gens. I'm not going into to detail about this, but check the FAQs page or ask around, many people know about it. It's good for throttle response, and maybe another 1 to 2HP.
More stages when I get back from break, lol....
06-22-2002, 12:16 PM
#2
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Join Date: Aug 2001
Location: Pimp'n ain't E-Z! But driving ur FD makes it easier!
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I'm back...
STAGE THREE: IGNITION
Now, I'm sure many of you are skeptical of ignition with mildly modified cars, and no...ignition will not gain you 10HP on a stock motor unless your running 150shot of NOS, lol...however, ignition WILL ensure a clean burn of the air/fuel mixture. Since you've get the air getting in better w/ your modified intake, and the exhaust getting out w/ the modified exhaust, then you should be sure the housings are clean for the next combustion cycle.
1. Of course, use NGK spark plugs. This is a given, some people have tried DENSO, myself included, and I couldn't tell a difference. Iridium plugs won't help you NA guys out at this power level. Just use the standard OEM plugs.
2. Next, upgrade the wires to a 8mm or larger. I love Jacob's wires, but Magnecor and NGK's are fine too. The larger wires will ensure no outside interference.
3. Upgrading the coil is the next step. Don't go wasint $400 on a jacob's pak, just get a nice piggyback system like the Crane HI-6 system. It will give a good powerful spark and there won't be anything left in the housings, lol. This is good for about 2 more HP.
STAGE FOUR: FUEL
Now is a good time to be sure the fuel system is running top notch. Your power level shouldn't be extreme enough to need HUGE injectors at this point, so don't waste your money or time. Simple upgrades is all you need.
1. Have your injectors CLEANED. I can't stress this enough. When you modify the car, you need that clean even spray! It's best to send your stock injectors off to RC and have them fix 'em up for you. Also, purchasing some T2 injectors for your secondaries isn't a bad idea either. They will come in handy if you ever decide to run NOS or similar.
2. Run an extra ground to the fuel pump. Every now and then I'll come across an rx7 owner who complains of low fuel pressure or fuel cut in turns. Most of the time, this is just a loose ground.
With these 4 stages completed, you are running close to 170 to 180 HP at the flywheel, which equates to about 136 to 144 HP at the wheels(for '86 to 88 NAs) and 185 to 195 HP at the fly or 148 to 156 HP at the wheels(for '89 to '91) depending on the condition of your driveline. This is about as much that can be gained with a stock port w/out NOS. Don't be discouraged though. There are other go-fast goodies that don't have to deal in HP...and I'll get to them soon....
STAGE THREE: IGNITION
Now, I'm sure many of you are skeptical of ignition with mildly modified cars, and no...ignition will not gain you 10HP on a stock motor unless your running 150shot of NOS, lol...however, ignition WILL ensure a clean burn of the air/fuel mixture. Since you've get the air getting in better w/ your modified intake, and the exhaust getting out w/ the modified exhaust, then you should be sure the housings are clean for the next combustion cycle.
1. Of course, use NGK spark plugs. This is a given, some people have tried DENSO, myself included, and I couldn't tell a difference. Iridium plugs won't help you NA guys out at this power level. Just use the standard OEM plugs.
2. Next, upgrade the wires to a 8mm or larger. I love Jacob's wires, but Magnecor and NGK's are fine too. The larger wires will ensure no outside interference.
3. Upgrading the coil is the next step. Don't go wasint $400 on a jacob's pak, just get a nice piggyback system like the Crane HI-6 system. It will give a good powerful spark and there won't be anything left in the housings, lol. This is good for about 2 more HP.
STAGE FOUR: FUEL
Now is a good time to be sure the fuel system is running top notch. Your power level shouldn't be extreme enough to need HUGE injectors at this point, so don't waste your money or time. Simple upgrades is all you need.
1. Have your injectors CLEANED. I can't stress this enough. When you modify the car, you need that clean even spray! It's best to send your stock injectors off to RC and have them fix 'em up for you. Also, purchasing some T2 injectors for your secondaries isn't a bad idea either. They will come in handy if you ever decide to run NOS or similar.
2. Run an extra ground to the fuel pump. Every now and then I'll come across an rx7 owner who complains of low fuel pressure or fuel cut in turns. Most of the time, this is just a loose ground.
With these 4 stages completed, you are running close to 170 to 180 HP at the flywheel, which equates to about 136 to 144 HP at the wheels(for '86 to 88 NAs) and 185 to 195 HP at the fly or 148 to 156 HP at the wheels(for '89 to '91) depending on the condition of your driveline. This is about as much that can be gained with a stock port w/out NOS. Don't be discouraged though. There are other go-fast goodies that don't have to deal in HP...and I'll get to them soon....
06-22-2002, 12:44 PM
#3
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Thread Starter
Join Date: Aug 2001
Location: Pimp'n ain't E-Z! But driving ur FD makes it easier!
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I've got some more time before work, so I'll continue on....
STAGE FIVE: DRIVELINE
This is probably the most overlooked and underthought of part of performance for most new guys. This will make sure all the power your making makes to the ground...
1. First off, get a good clutch! The clutch is what takes the stress of the power being pushed to tranny which is a lot of stress! I'd recommend a nice street/strip setup for the NA guys running mild setups. I prefer Centerforce and clutchmasters, but ACT and Bonez are good companies too.
2. Next, while you've got everything down and off the motor while installing that new clutch, throw in a lightweight aluminum flywheel. There are some steel ones out there, but the gain isn't worth $$ in my opinion. I recommend getting a nice 12lbs flywheel from Racing Beat or the 11lbs flywheel from Shane Racing. These flywheels will dramatically reduce your 60ft times and your "5th to 3rd gear downshift street race" acceleration. You will notice a drop in 0 to 60 as well.
3. If you really want to build an all motor application, but have a good motor and don't want to start tearing it down. See if you can't find an LSD from the GTUs Rx7. They have the 4.3 rear end in them as opposed to the NA/T2 4.1 and vert 3.9...The 4.3 rear end will do much the same as the lightweight flywheel as for your 60ft times and 0 to 60, however, you do sacrifice overall top speed in each gear with this mod.
Stage five will NOT gain you ANY HP. Its all there to ensure your HP gets to the ground safely and quickly. You can drop an easy .5 off your 1/4 time with stage five...if you've completely all the stages so far(1 to 5) then your STOCK port NA is looking at high 14s/low 15s in the 1/4 mile(really depends on the driver..but I'm basing this off of experience) and it leaves you wide open for motor work that will put you into the low 14s later on....
I hope this is helping some of you who are new to rx7s and NAs in general...I'll continue more on NA buildup later...I'm getting off work and going home to start tearing down the SE-X block...
STAGE FIVE: DRIVELINE
This is probably the most overlooked and underthought of part of performance for most new guys. This will make sure all the power your making makes to the ground...
1. First off, get a good clutch! The clutch is what takes the stress of the power being pushed to tranny which is a lot of stress! I'd recommend a nice street/strip setup for the NA guys running mild setups. I prefer Centerforce and clutchmasters, but ACT and Bonez are good companies too.
2. Next, while you've got everything down and off the motor while installing that new clutch, throw in a lightweight aluminum flywheel. There are some steel ones out there, but the gain isn't worth $$ in my opinion. I recommend getting a nice 12lbs flywheel from Racing Beat or the 11lbs flywheel from Shane Racing. These flywheels will dramatically reduce your 60ft times and your "5th to 3rd gear downshift street race" acceleration. You will notice a drop in 0 to 60 as well.
3. If you really want to build an all motor application, but have a good motor and don't want to start tearing it down. See if you can't find an LSD from the GTUs Rx7. They have the 4.3 rear end in them as opposed to the NA/T2 4.1 and vert 3.9...The 4.3 rear end will do much the same as the lightweight flywheel as for your 60ft times and 0 to 60, however, you do sacrifice overall top speed in each gear with this mod.
Stage five will NOT gain you ANY HP. Its all there to ensure your HP gets to the ground safely and quickly. You can drop an easy .5 off your 1/4 time with stage five...if you've completely all the stages so far(1 to 5) then your STOCK port NA is looking at high 14s/low 15s in the 1/4 mile(really depends on the driver..but I'm basing this off of experience) and it leaves you wide open for motor work that will put you into the low 14s later on....
I hope this is helping some of you who are new to rx7s and NAs in general...I'll continue more on NA buildup later...I'm getting off work and going home to start tearing down the SE-X block...
06-22-2002, 01:27 PM
#4
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Join Date: Nov 2001
Location: LA, USA
Posts: 1,622
Nice write up. You should have a page of this some where inthe forum.
I would also add, on ignition a degree or 2 of advance with high octane fuel.
On the clutch subject, would not recommend centerforce, been tru 3 of them, n/a and turbo and i was not impressed on the long run, they perform when new but once they are broken in, 2k miles later, they are no good and the disc just heats up to quickly, all my clutches had premature failure disc and pressure plate.
C
I would also add, on ignition a degree or 2 of advance with high octane fuel.
On the clutch subject, would not recommend centerforce, been tru 3 of them, n/a and turbo and i was not impressed on the long run, they perform when new but once they are broken in, 2k miles later, they are no good and the disc just heats up to quickly, all my clutches had premature failure disc and pressure plate.
C
02-12-2004, 12:06 AM
#7
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Thread Starter
Join Date: Aug 2001
Location: Pimp'n ain't E-Z! But driving ur FD makes it easier!
Posts: 2,705
I'm glad to see this post is still being read,lol...
On a side note ...when I worked closely with some guys for a rotary shop here in VA, this guy who had a shop behind the one we were using built ITS cars. He had an ITS FC that had 202whp to the ground. All that was done was completely fresh motor, STOCK PORTS, full ehxaust, headers, and a K&N cone filter. That guy could tune so well and from what I hear has built several high output NA engines. I don't recall if it was a standard 6port NA 13B or some kind of hybrid, but it was very impressive..there is def hope for you NA guys.
On a side note ...when I worked closely with some guys for a rotary shop here in VA, this guy who had a shop behind the one we were using built ITS cars. He had an ITS FC that had 202whp to the ground. All that was done was completely fresh motor, STOCK PORTS, full ehxaust, headers, and a K&N cone filter. That guy could tune so well and from what I hear has built several high output NA engines. I don't recall if it was a standard 6port NA 13B or some kind of hybrid, but it was very impressive..there is def hope for you NA guys.
