Engine mods for RX7

Hi everybody, Am new to this section of automotive forums and am not technically advance concerning engines,
I would like to ask you some quesions,
If you were to tune a japanese import(RX7 Turbocharged rotaries), which mods will you do first and why?

Is the pattern below correct? If not, why?
1/First i would like to change the induction to let more air in,
2/Then the headers, downpipes and exhaust (Medium diameter, for road use only, sometimes hard driving)
3/Then an uprated turbocharger & blowoff( even more air in)
4/Then uprated intercooler(cool down the air coming in, and more air)
5/Then fuel injectors( there will be a need for more fuel)
6/Then, the ECU, to fire more fuel in the cumbustion chamber(coz more air is present in there)
7/Then uprated fuel pump, push more fuel in.

Imo, I think these parts should provide a decent increase in Horsepower.Am I right?

Feel free to write your pattern and briefly explain why you choose to do it!! You may even write it in details(ground connections, spark plugs, turbo timer, boost controller,etc) because I presume mine is a brief one. One other thing, I don't know much about RX7 internals, so if you have a site describing it in details, please feel free to write down. Thanks in advance!

All are good mods for horsepower.

One thing I did notice is your number 5 should definetly come before number 3. If you are going to be putting more boost on the motor, your putting more air into the motor. More air requires more gas. If you upgrade your injectors after its almost futile. (End up leaning out your motor and blowing it up) 7 should also be tied into with number 5 at the same time. Bigger injectors are going to require more fuel.

Out of all of those listed , if you're serious about doing it, I would go with an ECU(number 6) first. When you mention it, I'm assuming your talking about a stand alone unit. Having a programmable ecu lets you manipulate an unprecidented amount of variables and is a quick way to free up some unprogrammed power. However, in order to tune an ECU, a wide band 02 sensor is a must! Don't let the motor become lean. (I believe the ideal ratio to be 12.1?) Also, 2-3 hours of dyno time is also extremely helpful.


Hope this helps...

^^good post.
1, 2, and 6 are good ones to start, and as random says, should be done first, even if they are done one-at-a-time.
All the others modify inter related systems and should be done at the same time, if possible,

I agree, although the blowoff isn't necessary. They sound cool, but a well designed wastegate will make better power. Blowoff valves allow the turbo to give off all of its energy as noise. I suggest only using them if you have a nasty re-acceleration surge that can't be otherwise tuned out.

A blow off valve is a crutch that sounds neat. A properly tuned wastegate makes no noise, but makes more power.

Thanks guys,
Speaking about turbos and blowoffs, If a turbo is a T04 or TD04(I think), what does this mean?
Is T51(T51R Kai and T51R SPL) a type of turbo or is it just a name given by HKS. Greddy has T78. Garett has T03 and T04?? Does these numbers have any meaning?

Yet another question,
During a quarter mile race, if your car is equiped with nitrous, do you press the button only once or several times or continue to press it as long as you wish? Does dry shot, wet shot or direct port N2O affect the number of times you press on the button?
If you don't understand, I can rephrase the part you don't understand!

Do you really have an rx7??

It sounds to me like you're just another kid who plays too much Need for Speed... prove me wrong??

Hey Hey Hey, I've never said I had an RX7 lol!!!! I intend to buy one in a few years. But for the time being I would like to clear up these things from my mind. Is ther any harm in it :p
Concerning need for speed, I played a lot, much more than a lot!!!! You cannot be wrong at this! Another thing, I knew about these aftermarkets, before NFS came out. You can ask me a question which is not in NFS if you want!

if you plan on using this car at the track you would probably want to upgrade the suspension and brakes (sway bars, shocks, springs, rotors, calipers, etc) to give you better control and such. Power is useless if you can't steer, or can't stop. If it's for streent use, those upgrades are good if you follow the already given advice.
On the subject of NFS, Need for Speed has to be the best street racing game i've played regardless of the fruit cake-like script and the emphasis on "tricking out your car" and lack of respect for sleepers. NFS2 is better in both those departments but could be better.

I can't really answer your T03 questions and what they mean exactly, but I do know that each manufacturer has their own numbering system and it may or may not equate to the trim of the turbo.

Maybe a member from the Forced Induction forum is cruising over here, or you can float that question in their forum for a faster response.

Thanks everybody once again, Roll cages also plays an important role if you are at the track, they help to reduce the torsional forces between the ends of a car
I'll post the question in the Forced induction section, But where do you guys do your readings, apart from howstuffwork?

Internet, ASE engineering textbooks, and asking questions just like you :)

First things first. I think it is very intelligent of you to be researching things like this now, this far in advance. One thing with heavy modifications is research is an absolute must. While every answer in this thread has had very good advice, my suggestion would be to ask similar questions in the rx7 forum as well. Every car (especially turbo cars) react differently to different modifications...every car has it's strong and weak points, and these need to be addressed specifically to 1) mod safely and 2) mod smart...ie best bang for your buck. You don't want to do things out of order and blow up your engine, and you don't want to spend $$ on something that is superfluous. So ask the rx7 owners as they will have much more specific knowledge and can point you in a much more direct path to follow.

Also not to dishearten you or anything, I have seen amazing rx7s, however they are rumored to be difficult to tune and end up breaking things when heavily modded. This isn't to say that other cars are better, I'm just saying they have that reputation.

As far as roll cages, yes they do have that effect, but that is not why some tracks require them...it is for safety. If your car is capable of running the 1/4 in under 11 seconds, many tracks require you to have a roll cage so you don't kill yourself if you crash at 130+mph speeds.

MHI Turbo Nomenclature

Mitsubishi Heavy Industries' (MHI) turbocharger nomenclature, such as TD04-13G-6cm2, requires some explanation. "TD04" and "TD05" refer to the turbocharger housing (either turbine housing or compressor housing or both), including the center housing (or CHRA or cartridge section). There are different styles of the basic housings and these have different suffixes appended to the basic designation, such as TD04L, TD04H, TD04HL, TD05, TD05H, and TD05HR.

TD04 housings have part numbers that start with 49177. TD04L housing part numbers start with 49377. Part numbers for TD04H and TD04HL housings start with 49189. The TD04HL compressor housing is easily distinguished from the others because of the integrated by-pass valve (see the pictures of the SL/MK TD04-18T hybrid below). The TD04LR-16Gk-6cm2 turbo (used on the turbocharged 2.4-L I-4 engine in the new PT Cruiser GT and SRT-4 Neon) is unique and not usable on our cars: the turbine housing is cast into the exhaust manifold, the impeller spins counter-clockwise, and the bypass valve is cast into the compressor housing.

All TD05, TD05H, and TD05HR housings start with 49178. The TD05HR turbine housing (found on the Mitsubishi Lancer Evolution IV through VIII) is a twin scroll design. All the other TD04 and TD05 turbine housings have a single volute in the turbine housing. Like the TD04LR, the "R" in the designation refers to the fact that the turbine wheel spins in the reverse direction (counter-clockwise) compared to the standard TD05H turbine.

The MHI part numbering system, and the possible combinations, can be somewhat overwhelming and confusing. For example, the MHI Sport Turbo Upgrade for our cars is usually referred to as the TD04L-13G-6cm2. This turbo clearly has the standard TD04 (49177) housings (at least by external appearances). However, both the stock TD04-09B-6 and the upgrade TD04L-13G-6 use the 49377 cartridge (but note the different complete part numbers) from the TD04L turbos. TD04 turbos used in other cars (even some other TD04-09B turbos) use the 49177 cartridge.

The "13G" in the model name refers to the compressor wheel. The "13" is the size and the "G" is the style. The 13G wheel has an exducer (or base) diameter or 2.000" and an inducer diameter (air intake opening) of 1.580". All MHI wheels I have seen have 12 blades. Blades are always evenly spaced, but the pitch and height of the blades can change between models. "B"- and "C"-style compressor wheels have all blade tips at the same height. "G"-, "Gk"-, and "T"-style wheels have blade tips at two heights, alternating high and low.

Mitsubishi does not seem to use seperate designations for different size turbine wheels, other than the TD04, TD04H, TE04, TD05H, etc., designation. The "6cm2" in the model name is similar to the A/R ratio used by other manufacturers. The "A" in an A/R ratio is the cross-sectional area of the smallest intake passage in the turbine housing before the passage spreads around the circumferential volute that leads to the turbine wheel. The "R" in the ratio is the distance from the center of the "A" to the center of the turbine wheel. The MHI "6cm2" designation is just the "A" in the A/R ratio, that is, it is just the cross-sectional area. Like A/R, the smaller the size of the "cm2" number, the faster the exhaust gases will discharge onto the turbine wheel, and so the faster the spool up will be (less "lag"). The size of the "cm2" number or the A/R ratio also determines the amount of exhaust gas backpressure and, thus, reversion into the combustion chamber. A larger "cm2" number (or larger A/R) means less backpressure at high exhaust flow. Extreme Turbo says that the TD05H-7cm2 housing is equivalent to a 0.50 A/R. The Rocky Mountain DSM turbo guide presents the following conversion between Mitsubishi's "cm2" number and the standard A/R.
6 cm2 = 0.41 A/R
7 cm2 = 0.49 A/R
8 cm2 = 0.57 A/R
9 cm2 = 0.65 A/R
10 cm2 = 0.73 A/R
11 cm2 = 0.81 A/R
12 cm2 = 0.89 A/R

Whoops, forgot to give credit where credit is due...that whole turbo nomenclature writeup was taken from here:

http://www.stealth316.com/2-turboguide.htm

Thanks bros, this really helped. Thanks a lot. From now on, i'll be at the RX7 forum. Thanks once again