Power

[GTwizard]

TUFFTR
I only recomended the VR4 heads as you kind of indicated money save was most importent. You can really onlly do mild port and polish on the VR4 heads or a port match as these heads do not have enough beef to do much more that that. If you wish to do a good set of heads, you will need to have the NA heads worked. Some of the best motors in the world have come from your neck of the woods. Take you time and try to find a head guy out there with a good rep and talk with him. My heads were done by Wells Racing and they are not Mitsu guys at all. They for the most part build big block race engines. But there head guy was one of the best at the time we had our heads done. So we used there service. Do not get used valves and springs. You might consider a used set of stage 3 heads that have allready been fully worked and can be had from a part out. That might be a good deal. But buyer be ware. If you are really going to go through the trouble of going after what might be the best motor you can build for your self, please take the time to do it right. What an other year. LoL. This is not something you can take take lightly or scrimp on. Do it, or do not. Kind of like buying 3 really good tires. I don't think you would do that, would you. Same , same.
I did not build my motor all at once. But I did try to do it in steps that would allow me to take advantage of each step and see more power each time along the way. There was no sence for me to get big cams if the heads could not breath. No sense in doing heads if we could not corrct for AFRs. So an AFC Neo was first. next came all the head work. That was the biggest cost and got it out of the way. About 2 grand complete. The heads allowed my stock cams to come alive. Damn those stock cams made a ton of low end torque. Next was exhaust, than headers. Ran like that for about 2 years saving for the next step. Car was realy fun to drive at that point. from there I had to decide what was next. Not what to add next. what was it that we were going after. Was this to be a drag car? or a road course car? Or just street monster? If I ask you what are your goals, you will say more power and maybe just how much. That is not an answer. You can not build a drag motor and run it on a road course or circle track. Not going to happen. It will not last. Can't build an endurance motor and take it rock climbing or it will not perform well under those conditions and will not last. You must know what you goals are, the application you wish to use your car most and your expectations. You sure as hell may not won't what I have. It may not be right for you. You can build a motor for Max GRUNT low end power or high RPM throttle responce. It will be hard to do both. Not going to happen. I have chosen the latter. I am an RPM NUT and I do not recommend this for everyone. Good example would be 2005 Grand Prix motor. 3.0 liter V10 that make 840 hp at 18,700 red line but only 300 ft lbs torque. No torque needed at those RPMs. Could not drag race with that motor. get my point. You must decide on the application and build for it. Last year I jumpoed the gun and had endurance cams made. I did not have the intake to support such cams and was a waist of time. Too much too soon. So now I have backed down to the HKS 272s and life is good. I have the intake and exhaust to support these cams and all is working OK. Do not get ahead of your self like I did. Slow down and take your time. Take each step one at a time and complete that step. If you cut corners, you are just spending money with little results.
x2percentmilk
As I was explaning to TUFFTR. I can not give a best bolt on for power. Let me explain. Your engine and driveline are a packaged deal. It was ment for John Q public. Saftey, performance and reliability, at an affordable price was the goal. Now you wish to alter that. A good bolt on like turbos or blowers will force the motor to run well above the intended uses of this drive line package and can work well. There is a cost to do it right however and is not cheap. Your other alternitive is to alter the package. This is what we are doing. This package altering is just as costly and can hurt or even fail if nopt done correctly. Just as a turbo car that run lean and melts pistons, we can huirt the NA package as well. You must have a goal as stated earlier. You must be able to tune you mods as a bad tune will make all you work for not. It is tuning that makes or brakes power. Your ECU was designed to compensate for most all normal driving conditions and normal are and tare on the motor. Once you begin altering the peaces it was ment to work with the ECU may not be able to compensate for you mods. This is what happens and why we need some way to alter what the ECU is seeing. That what these tuners do. It allows us to fool the ECU. The AFC stuff works well. Even the little NEO worked good for us. I just ended up going a different rout so I use something else at this time. And x2percentmilk, you are not understanding your tunner. We can cover that latter. I can help, but this is already too long. This is a lot of food for thought and there are some out there that might just disagree with all that I have just spit out, And that's OK. These forums are to help us stay on track with our thoughts and help us make usefull decission about what we might or might not do.

[GordonRamsey]

Cams. Before you look at cams, you need to do springs. You are already reaching Valve float. A much more agresive cam grind will cause those heavy stock valves to open at a much grater speed than before and they will want keep going LOL. and on the closing side of the ramp, the rate is so fast, the valve will be slow to react and you could even drop a rocker. Spring will help keep your valve time presice. With out good spring rates your valve trane timing will get really sloppy and at an RPM range much less than what you are running now.. Extream duration cams need high compression. lower comp motor need high lift. That was an issue I had last year. I was trying to run endurance racing cams, but did not have the compression todo so. My valve trane will handle any and all cam grinds and at RPMs I could most likely never reach. But I did this so I could test mutiple crazy ass grinds. You should do well with the cams that I run. HKS 272s intake and exhaust. But, with out springs to back it up, your waisting your time. I also run extreem light weight valves to insure no valve trane slop at all. Springs and Valves are not that expensive. It is a good port and polish that runs into time and money. You should also remember that the shape of the valves has a lot to do with the amount of air that can get around them. It will be your heads that make real power. After we had our heads done, even our stock cams felt huge. Low end responce was nuts and would rev till the fuel shut down.. Did not go with better cams untill we had a set up that could take advantage of more lift and more duration. You might even consider VR4heads as they flow a little better. For the power you are looking for, it time to cosider your next step as completing a package. Heads, cams, valves and spring need to be done all at once. To try and do this in a peace meal fastion or one step at a time could just lessen the power you already have. Or at least be a disapointment.

How much mroe CFM do the TT heads flow than NA's?

[GordonRamsey]

Theres alot of false info that floats around the internet, especially with something like N/A tuning where not alot of people have solid numbers to go off of. This is a huge bit of good information that most of us can agree puts to rest the "what single upgrade helped your N/A the greatest?" question. I can bet alot of us here would rather do things right then waste our time and money on something that wont matter or will destroy our cars.



To pose a new question to everyone, ive been looking into fuel control. From what I can tell a VR4 pump with the stock NA injectors should hold ground, at most maybe some of us might need stock vr4 injectors, but what about fuel control?

As my car is my daily driver i've been looking into the SAFCII as it has 2 tunes for low and high throttle. My gas mileage right now is no where near what id like it to be, so I figure thats where the low throttle tune comes in, as I can lean the mixture out as much as possible up until say, 3500 rpsm which i barely reach at 5th gear cruising on the highway. Then I assume the high throttle value we want to tune for 14.7 afr, or do we want to go as lean as possible without knock and timing changes? What happens in the "middle" throttle? Was my gas mileage assumption correct? Also, is exhaust gas temp needed if a good wideband is being used?

I feel like alot of people know these answers from tuning experience, so given that I have none, id figured id ask

You're never supposed to tune for 14.7. For one it is unreachable. thats what a stock ecu strives for. but if you can watch the A/F ratio it bounces above and below but NEVER TOUCHES 14.7.

[SOHC]

I'm planning a big na build for my sohc and the stock tb is only 54mm. I can get the DOHC 60mm as an upgrade and I see people running larger throttlebodies on there na's. I was wondering if I'd see any gains with a 70mm vs. a 60mm DOHC throttlebody.

http://cgi.ebay.com/ebaymotors/90-99...Q5fAccessories

[colt45 gto]

it sure is pretty, its CX racing, dont see why you cant run a larger TB, your motor can only suck in what the cam and valves alow it too.

rule of thumb on the old way of tuning N/A's inc V8's was to drop 4 pot holly carbs on for greater performance, so it can suck air at a better rate. remember what it sucks in it has to blow out!

[TUFFTR]

Of course it's a better upgrade to SOHC's. Less restriction in the intake. I always found this Bigger TB thing funny, Being in Australia I went out and measured my SOHC TB, DOHC 3L TB, and DOHC 3.5L TB, and they were all the same! Pretty sure they were all a 54mm internal diameter, will have to double check that though....


WIZ - Understood mate. Like you said, I too am doing bits at a time. I got qouted $1000 for custom made extractors. I said - eh, bit too much I think. Found a set of 6G72 SOHC 24v extractors back to the cat for $200 to my door! I said thank you very much! I already have the manifold plates to get welded on, just will need a bit of modifying to work, But hell, I doubt there will be $800 in modifiying for some pipes so here hopes I got me a cheap set of extractors! The engine pipe will be going on the Diamante of mine to open that up a bit (God the stock merge pipe on a V6 is a fucking joke!)

I run a full replacement ECU so I tune and alter all the time, Really making the most of what I have. It's only ever had 1 dyno tune and I've been working on that since. When I land a P/T job I'll be buying a few more hours dyno time to get torque sensing set up properly.
Goal - Weapon of a street car - with a proper drag race once in a blue moon (Did it this year and was a BLAST!!) it ran almost a flat 15 on a damp track, on heavy 19" rims all around, with a bogged launch. Was VERY happy with that. in current trim I can see it doing a mid 14 no worries at all.
Would like all the power up top, 3/4-7/8000RPM would be ideal. Slowly working on it.
I would like to get a set of 2nd hand cam's but it seems they are ALWAYS popping up so it's no REALLY big rush to get a set SOON kind of thing.
Guess I just need a P/T job and to start saving again!

[GTwizard]

How much mroe CFM do the TT heads flow than NA's?

you can find the flow info at 316stealth.com

[GordonRamsey]

I always forget to look there.

Can anyone iterate on my 14.7 "stoich" comment?

[GordonRamsey]

Hmmm.. it confuses me that with the head work you see a huge amount more gained in cfm in exhaust than you do intake. Are these stock cams ground for low end? And can anyone tell me why the TT head table has "XXX-XXX" (a dash in between the numbers)

I believe GT wizard said you can take more out from the NA? Wouldn't that just mean that you can take the same amount out as the tt but the tt is just already started as a larger diameter? (porting)

I also find it interesting that almost all the power separating awd's and fwd's is in the turbos. They should have known the fwd's would be turboed one day.

[GTwizard]

Hmmm.. it confuses me that with the head work you see a huge amount more gained in cfm in exhaust than you do intake. Are these stock cams ground for low end? And can anyone tell me why the TT head table has "XXX-XXX" (a dash in between the numbers)

I believe GT wizard said you can take more out from the NA? Wouldn't that just mean that you can take the same amount out as the tt but the tt is just already started as a larger diameter? (porting)

I also find it interesting that almost all the power separating awd's and fwd's is in the turbos. They should have known the fwd's would be turboed one day.

Don't have a clue about the dash. And why does it matter how a company uses part numbers. But these are different casting. Just as Chevy has about 900 different casting for the small block. We are lucky to have Only 2. There are multiple forums on head porting design and much of this is try it and see. Thare are threads about closing up the base of intake ports as this can increase velocity of an incoming charge at high RPM.
There are also threads about smooth bore runners and ruff bore runners. Each can show an improvement depending on what you would like to believe.
Not sure what you mean when you say "They should have known". That is like saying they should have know you were going to buy one. That makes no sense at all. Not at all. I do not belioeve that most NA's have gone turbo. Not many at all. NA flow patterns differ from turbo. Need to go back to school for that if you wish to under stand the requirment of each. Otherwise you would have 1 head that fits all. Keep in mind that all cars are designed for John Q public. No one gives a rats ass what you or I want or what will do with the car after we get it. Just because you want brembo brakes does not mean all cars should come with brembos. Get the idea. There is a tons of money and sometimes years of time and consideration that goes into the design of a car that will be mass produced. These motors are ment for standard road and highway use for the average consumer. If you wish for something that is not average you would go buy a Lambo or some other freakish car that will blow your skirt up with out touching a wrench. Should "they" also know that I don't wish for grunt but only RPM, or that you wish for grunt and no RPM. There is no motor that fits all catagories of street and racing needs. This most likely does not answer some of your questions, but may help ajust your trane of thought.