2 Questions - Exhaust System and Spark plugs

[Grandavi]

Added this summary up top for those that are curious, but would like to save the time of a massive read... lol
The question is BELOW the summary!
I have decided to run OEM Platinum NGK's (the OEM just means... TSRM specified) as I am not upgrading high enough to warrant fudging with Iridiums or lower temp cores.
Also, I am going with a 3" catback exhaust (will post pics when it arrives), test-pipe or magna cat to replace the stock catalytic converter (will decide at time of purchase and add pics when it arrives as well), and a 3" downpipe with integrated wastegate (again... will decide yada yada.. ).

The last part of the discussion (around page 10...) goes into dealing with the valve cover gaskes and spark plug galley cover.
There... that will save you time if your just curious...

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ORIGINAL QUESTION!

Hopefully this will come out as an intelligent post from somebody that is confused... lol. Or.. in otherwords.. some of this may come across as "stupid questions". Please be patient with me as I learn.

I have 2 questions, and after reading a whole lot over the past 2 months, I can't make a final decision on direction to go. The first area i am attacking on my 88 7MGTE is the hoses (all vacuum hoses are being replaced). Thats a simple no-brainer... My second area is the exhaust system and thats where I am stuck.

What I want to do with my car is get it to 300HP+. I dont see the need for 400 HP+ as it is my daily driver, but I do want the engine to run flawless as possible and last as long as possible with proper maintenance. (just to give you a bit of background)

I have read and researched a lot of exhaust systems, but have gotten to the point that i have too much info and not enough practical knowledge (ie. what works best) so I cant decide on which way to go. Utilizing the Stock CT26 turbo, I was wanting to go to 3" exhaust. So, I need to be corrected or verified on my assumptions...
1. I have been told that if I go 3" on a stock 7MGTE, I may end up losing low end torque as the turbo needs a little backpressure to spool up. Not sure if this is true.

2. I want to get a 3" catback exhaust, but dont know if I need the cat still when I live in Canada. I dont think its the law that I need it, but am more concerned that if I remove it, I will be screwing up the info the ECU gets somehow. I assume the 3" catback exhaust comes with the muffler, but am not certain. Does anyone here recommend a certain brand or set-up? I am aware that catback means.. "from the catalytic converter - back" but have mixed info on removing the cat infront of this. (mine is fine.. I could just leave it as long as its not going to cause a performance issue)

3. I think I need to upgrade my elbow/downpipe. I have seen a couple solutions to this (as the stock one apparently has a design flaw that builds up pressure) but can't decide on what would be the best "bang for the buck" solution. Hoping someone who is happy with theirs could share what they put on to help.

4. Do I need to get a downpipe if I keep the turbo stock?

5. Do I need to get a tuned header/exhaust manifold? Without upgrading/modifying my turbo, I am assuming that the stock manifold is fine.

I just want to do the whole exhaust system (from the block to the rear bumper) properly the first time and hope somebody can point me right so I dont end up doing this improperly.


The second question was regarding platinum spark plugs. I was talking to a mechanic last night regarding upgrading my plugs and stated I was going double plat. He told me on a turbo that that would be a mistake as they will melt slightly at high temp (run too hot) and cause other issues. (First I have heard of this...)
Therefore, he recommends I go with irridiums. They are a bit more expensive but if they are the best, then thats what I will go with. Any thoughts?

Thanks all for reading, hope I didnt ask this wrong.

 

[grimreaper]

1. I have been told that if I go 3" on a stock 7MGTE, I may end up losing low end torque as the turbo needs a little backpressure to spool up. Not sure if this is true

this is for figgie
Figgie its the bat signal!

good 3" turbo back will be fine, find a cat back that you like the exhaust note of and your set.

 

[figgie]

grimpreaper...

LMFAO!!!
For real. You made me spew water out on that one.. Good one!


Grandavi

welcome to the forums.

The reason grimpreaper posted that little batman skit is because of me (see my title).

But since you are new, the answer is back pressure does not exist

Exhaust pressure is what you are refering to.

The turbo works on pressure differential between the exhaust manifold and atmosphere (that is what the Downpipe and exhaust exhaust too). The greater the exhaust pressure ratio the faster the turbo will spool. What this means is that basically on a turbo car, you want as big as you can handle and the turbo can flow.

On a ct26. Nothing more than a 3" from the turbo back as 4 inch will not gain you anything on a ct26.

On the spark plug end...

Toyota is stock Platinum. Good for the stock to a bit above stock pressure on our cars.

Irridiums. Not needed and just a waste of $. Plats and preferably copper.

 

[Grandavi]

good 3" turbo back will be fine, find a cat back that you like the exhaust note of and your set.

That's part of my problem, I dont have a "home network" of people who have upgraded their exhausts (being as old as I am, most people my age that I know are buying new cars and dont care...)

I just want a full exhaust system (3") to allow my car to run as well as it can (stock) without sounding like the guy next door (crappy little blue chevy with 3" exhaust that sounds like someone farting in a garbage can). Quieter is better for me and I have been leaning towards HKS's solution.

Hopefully this isnt another stupid question.. but the catback's do include the muffler do they not? The descriptions are "iffy" for those who have no idea what they are talking about.. lol. (note: I have rebuilt engines.. but never mod'd one)

Figgie... loved the old batman.. was wondering about that vid
You responded when I was responding.. so now I will respond to your response.. lol.

The spark plugs in the car are currently garbage cheapies... I have looked at NGK and will probably go with those. The wires are gone, so I will be upgrading those too.

Will it hurt to go 4" (or make it excessively loud). I dont see a huge difference cost-wise to go 4" and that would allow me to upgrade the Turbo later if I'm not happy. I dont mind going the extra $$ to do it right and I definitely dont want to pigeon hole myself by upgrading too low. The more I learn about the car, the more I can see the reasons behind a lot of upgrades and would like to not do anything twice. I have entertained upgrading the injectors and maybe modifying the CT26 (or going with a larger turbo), but that would happen after the exhaust upgrade, hoses replaced, hardpiping the intercooler and upgrading the radiator (not necessarily in that order). My biggest reason for not upgrading the turbo right now is that I dont see the cost/benefit to doing so. Sure I will have lots more RWHP, but Im not going to the track, and by upgrading the turbo, I gotta look at the intercooler. then I may as well look at swapping to a JTZE.. probably cheaper in the end if I understand it all...

 

[figgie]

Grandavi

old as you are?

you would be surprised the age of alot of folks in here

being in calgray, they salt the roads there. Not that big an issue since you probably do not drive the supra in the winter... but come spring. The car comes out. They usually do not clean the roads until mid to late spring.

You can do a 3" turbo back system

ALL cat backs have a muffler. Some cat backs have a resonator, some do not.

For a quiet exhaust, the Tanabe Hyper Medallion is as quiet as it gets but yet opens up nicely at WOT.

 

[grimreaper]

If quiet is the name of the game, tanabe hyper medallion. LOVE mine, its on the opposite end of the spectrum as "fart cans". cat backs include the length of pipe from, well, the cat back (including the muffler and any silencers). I would search youtube for differnt exhasut sounds you like, because some like open dp's and others love the stock exhaust note.

Damn figgie, you used your moderator powers to read what i was typing didnt you!

 

[Grandavi]

Ever watch the original Batman movie with Adam West? Laughed so much I almost peed myself. When I was a kid.. I thought everything they did was serious... lol. Now that I'm older.. I understand the "adult humor" side...

Just peeked at the Tanabe Hyper Medallion exhaust.. that looks perfect. So.. I can sign myself on the catback portion.. now I need to know about what to replace infront of it... Am I looking at header + divorced downpipe? And can I replace the cat with either one of those "racing cats" or just straight pipe? Can't find anywhere that says we need cats in Canada, so I believe Im fine getting rid of it.

 

[figgie]

The spark plugs in the car are currently garbage cheapies... I have looked at NGK and will probably go with those. The wires are gone, so I will be upgrading those too.

Will it hurt to go 4" (or make it excessively loud). I dont see a huge difference cost-wise to go 4" and that would allow me to upgrade the Turbo later if I'm not happy. I dont mind going the extra $$ to do it right and I definitely dont want to pigeon hole myself by upgrading too low. The more I learn about the car, the more I can see the reasons behind a lot of upgrades and would like to not do anything twice. I have entertained upgrading the injectors and maybe modifying the CT26 (or going with a larger turbo), but that would happen after the exhaust upgrade, hoses replaced, hardpiping the intercooler and upgrading the radiator (not necessarily in that order). My biggest reason for not upgrading the turbo right now is that I dont see the cost/benefit to doing so. Sure I will have lots more RWHP, but Im not going to the track, and by upgrading the turbo, I gotta look at the intercooler. then I may as well look at swapping to a JTZE.. probably cheaper in the end if I understand it all...

Well cheapie is fine

Autolites Coppers, NGK coopers, Champion Coppers are inexpensive That why copper is good!

On the exhaust side.

4 inch. You will not like at all. regardless of how many muffler you put on a 4 inch exhaust it will be LOUD. 3 inch is good for up to about 500 hp

 

[grimreaper]

imho, leave the header, get a bic (or defcon) recirculated dp with flex and cermic coated (not painted!) and a test pipe (strait pipe) for the cat. should help remove a cool grand from you pocket

 

[figgie]

If quiet is the name of the game, tanabe hyper medallion. LOVE mine, its on the opposite end of the spectrum as "fart cans". cat backs include the length of pipe from, well, the cat back (including the muffler and any silencers). I would search youtube for differnt exhasut sounds you like, because some like open dp's and others love the stock exhaust note.



Damn figgie, you used your moderator powers to read what i was typing didnt you!

lol

NAH! I was one of the first one to be running a Tanabe hyper Medallion. Loved that exhaust. So quiet. And being stainless was a big plus too.

Just peeked at the Tanabe Hyper Medallion exhaust.. that looks perfect. So.. I can sign myself on the catback portion.. now I need to know about what to replace infront of it... Am I looking at header + divorced downpipe? And can I replace the cat with either one of those "racing cats" or just straight pipe? Can't find anywhere that says we need cats in Canada, so I believe Im fine getting rid of it.

Turbo cars do not have headers Those are the Naturally aspirated cars.

We have exhaust manifolds. On a ct26 or slightly upgrade turbo. There are bolt ons to put onto the stock 7m exhaust manifold. From the turbo back. That is dependant on the turbo.

For a ct26. there are lots of options. Turbo elbow + dp. integrated turbo elbow AND dp. becauseican (Randy) sells some nice ones.

As for that Catalytic convertor. You can remove it and replace it with a test pipe or a high flow cat. The power loss is minimal anyway As to remove it or not. I am not familiar with Candian law and GrimJack is out of town this week.

 

[jdub]

Autolites Coppers, NGK coopers, Champion Coppers are inexpensive That why copper is good!

Use caution using the Autolites, especially with aftermarket wires...they are 1/8" shorter than the JIC standard used on the 7M. You can get an idle misfire or fouling due to arcing. The NGK coppers are my choice

 

[figgie]

Use caution using the Autolites, especially with aftermarket wires...they are 1/8" shorter than the JIC standard used on the 7M. You can get an idle misfire or fouling due to arcing. The NGK coppers are my choice

On that note. Scratch the autolites!

 

[starscream5000]

I'll put in my two cents on some points as well:
1.)Coming from personal experience, a 3" exhaust seemed to add power all across the board on my car. I did not notice a drop in power ANYWHERE.

2.)The MKIII is not OBDII, so no worries about the cat being removed. Just make sure you don't get yourself in trouble doing so. My suggestion, keep the cat in your garage, and put a testpipe on, or even a testpipe with an integrated electronic cutout pointing towards the ground for all out power when racing. I recommend the RSR GTII for all out power from a 3" catback. You probably won't get more power out of any other 3" out there. I personally use this one, but it's loud as hell. Be advised though, this exhaust has been discontinued, so it may be hard to locate one. 935 motorsports should sell a replica exhaust of this for cheaper. Choose your catback based on your personal tastes. They are all going to rob power when bolted up to the cat/testpipe if you've already got a 3" turboback up to the catback.

3.)Here's where you're going to see the most gain out of a new exhaust. I personally used a Cooleeze 3" downpipe with integrated elbow. The supra was a completely different car once I put this on it. Again, the DP I have is no longer being sold. But I would recommend the Recirculated Divorced Down Pipe that 935 Motorsports sells, that would be one of the most cost effective solutions that would net you nearly maximum gain.

4.)As above, I highly recommend this mod

5.)This is not needed for your goals, nor would I advise it to you as you would have to modify the Downpipe, coolant lines, oil lines to make this work. The stock turbo manifold has proven to flow over 500HP.

 

[supradjza80]

I have yet to figure out why everyone thinks copper plugs are the best. Yes copper is a better conductor then both platinum and iridium. It is not nearly as strong however, leading to a large electrode and more spark plug changes (I prefer to change plugs as little as possible, less risk of stripping the threads in the heads etc.)

Spark plug manufacturers use iridium as performance plugs and have the data to show the improved performance over the other types of plugs (go look at denso's website if you don't believe me...). The reason you gain performance is due to the huge (HUGE) decrease in area at the end of the center electrode on an iridium compared to a copper plug.

I run the Denso IQ-20's and couldn't be happier. I would rather spend $8/ plug once instead of $3/plug 3 times over the same mileage or per oil change or however long it takes the coppers to foul out.

That's my $.02, but if you like to change plugs unnecessarily please by all means keep doing it.

 

[Grandavi]

FINALLY! lol (and I am chuckling out loud at myself).

I have the answers ... believe it or not.. I have asked this question to probably 15 people and come up with about 30 half-answers... leading to my overall confusion...

So... this is my plan.. from what I have read here.

3" catback system, downpipe with divorced wastegate (believe thats correct terminology), custom turbo elbow. and replace the cat with a testpipe. All sounds perfectly straight forward now. (all the pieces...)

I will post exactly what I will be getting now in a response once I grab all the names just so I dont accidentally screw myself up again.

as for the sparkplugs... NGK's... and I am replacing the wires with Magnacats 8mm... (cost less than stock and seem to be higher grade). Actually.. now that I read Supradjza80's response.. I may just foot the bill and go iridium... I think they have a higher maintenance schedule, but i dont mind if it means feeding my baby properly... (not sure if it's Denso's I want though... I think I saw a webpage that had some different "new" iridum out... if there is any difference... but they may cost even more!)

Now I can actually budget for this.. lol. Next will be the rad.. already pretty certain I am going with Koyo Racing 4.8 1JZ JDM liter Radiator upgrade.. costs about 450 I believe. Unless someone has a smarter answer

Thanks so much you guys! its a huge relief to feel the lightbulb start to go on...

 

[supradjza80]

http://www.globaldenso.com/PLUG/power/features.html

 

[jdub]

It's not the spark that makes the difference, it's copper's ability to conduct heat away from the tip. After an extended high speed/boost run (especially on a high HP motor), iridiums can "glow plug" due to the heat...minor detonation (ping) at boost makes it worse. If you experience this, pre-ignition can result and that will torch a piston in a heartbeat.

On a stockish motor, iridiums are fine. I highly suggest you check the gaps...be very careful touching the fine tip though

 

[Grandavi]

On a stockish motor, iridiums are fine. I highly suggest you check the gaps...be very careful touching the fine tip though

The gapping issue was the main reason I steered away from them... I think the car has coppers right now. The only reason I considered double platinum or iridiums was the Toyota Dealer mechanic said that I had to run platinum as a min requirement for the engine.

 

[supradjza80]

From what I understand, going to a colder heat range (just as you would with a copper plug) at high boost fixes this problem.

 

[supradjza80]

The gapping issue was the main reason I steered away from them... I think the car has coppers right now. The only reason I considered double platinum or iridiums was the Toyota Dealer mechanic said that I had to run platinum as a min requirement for the engine.

I gapped my iridiums and it was extremely easy, you just bend the ground electrode and then slide your feeler gauge in between the center and ground electrode until it has the correct "gap" you are looking for. You just cannot leave the feeler gauge between the electrodes when you gap the plug because the electrode can dig into the feeler gauge and when you pull the feeler gauge out you will brake the electrode. It is really easy to gap the plugs.

Oh and the toyota mechanic is full of it, he probably says that you need iridium's or platinum's just so the plugs last 60k miles like the TSRM says the plugs should.