non-VTEC

nice job tony....keep up the good work...

Tony the Tiger

Shock from wheel hop, or a lot of slack in other parts of the driveline will stress gears differently... Power/torque is not as significant as shock actually. Just picture a Civic with a stock B16A can still snap axles and still shred a gear with bad launching/shifting techniques, while enough people have jammed out 500+ WHP and running 10's on the same transmission...lol

I learned from this, and I have always set up my own personal cars to have very controllable power and keep a few key items which dampens shock. e.g. My Supra at 1444 WHP still uses the OEM dual mass flywheel and rubber driveshaft coupler at the diff. My 1000WHP Camry still uses a sprung clutch disc. Better to break some clutch disc springs and replace a clutch disc, than to change/upgrade axles or blow the transmission. Less shock is also better chance for traction too.


Thanks Lui

Flr Power

Tony, I am wondering why do you prefer tuning with a flat torque?
I am assuming you do it to help control wheel spin?

D-Rob

It's efficient. If you hold torque flat to a high engine speed, you make a bunch of power without the part-killing torque.

wantboost

iTrader: (2)

it's also much more enjoyable to drive

Schister66

Impressive build...Tony, your work never ceases to amaze me

wantboost

iTrader: (2)

I need to pick Tonys brain about my dual plenum 46mm itb setup for my gt2871r, 10.5:1 ls/vtec build one day.

cpccfab

love the sound of J-series motors. great build by the way.

wantboost

iTrader: (2)

I've never seen tony build a car that wasn't well thought out, well detailed, and well executed

tony, can I come to Canada and build cars with you? pretty please?

Flr Power

He sure does. Also, the number of build cars he has done in just a few years is unbelievable. He really get things done. All his personal cars are crazy fast, especially the Supra...

Tony the Tiger

A flat torque curve is efficient for just about everything. From stress on the driveline, to better traction (and holding traction), predictable for tuning, and a much better driving experience as well.

If the parts are selected right, the engine is becoming more of an all motor engine. I've always like using the S2000 as a prime example, and as witnessed over the years, it has become one of the best engines to be boosted. Due to its great efficiency, it has overcome the dangers of high compression and high RPM power with smaller turbo choices, and very responsive. Although an engine like this, will become very picky on certain parts like exhaust manifold type or style, or minor changes in turbine A/R and there is always a reason why it behaves like that.

I can't just "tune" for a flat torque curve on my laptop, but I'll know how to tune an engine that makes a flat torque curve and take advantage of it. The engine has to be built and parts have to be selected to obtain this flat curve. For example, you can't just tune a J-series V6 to breathe a flat torque up to 8000RPM. It's a whole system altogether with the biggest variable being the turbo itself working in conjunction with a high efficiency motor.

Our common example in the Honda scene, would be trying to run Skunk2 Pro 1 cams with a GT28 turbo and a log manifold on a low compression B18 VTEC in hopes of making power up to 9000RPM. Wouldn't that be great with full spool at 3800RPM and carrying it up to 9000RPM? We know that doesn't work well due to the turbo-related parts hindering the N/A-combination of the engine. The overlap from the S2 Pro 1's needs to scavenge, but the turbo system won't allow it at certain RPM's. This setup doesn't need more cam, but needs more exhaust flow.

Additional exhaust flow can be achieved many ways, from tubular manifold, larger turbine wheel or housing, bigger downpipe and exhaust, staggered cam choices, etc.. the trick is to know what to choose, and choose it by a condition in which the turbo may start choking or out of efficiency, at specific RPM's and specific running conditions/scenarios. We shouldn't choose a method that defeats the purpose of other supporting parts (bigger turbo will help, but defeats the purpose of a GT28 early spool), or defeating the purpose of the car.

Flat torque curve puts less strain on all the supporting components of the engine/turbo system as well. Turbos can make just as much power with smaller sizing. The engine is more efficient and uses less of everything. Less air needed to make the same horsepower means it requires less intercooling and uses lesser fuel flow; as a result, it creates lesser exhaust gases so you can make more power on the same turbine flow. In an overall package, by going smaller in everything else (smaller turbo, smaller intercooler, etc..) automatically grants you better spool and response in the same HP package with the same engine displacement. It's always a win-win situation.

Newer supercars are also striving for the same goal. With the R35 GTR, only having flatter torque curves as the year progresses. Newer performance oriented turbo cars are the same, as seen by differences between the old Evo 8/9 4G63T and the newer 4B11 Evo X motor, again, breathing a wide and flatter torque curve on the newer model and about the same power on a smaller turbo.

Flr Power

Tony, you know your stuff.

You also know you can get a flat torque curve by proper boost management. That is what is so good with a turbo. You don't have to tune with a flat boost line. When I look at your Supra flat torque output, it is obvious to assume the engine did not see a flat boost line. Awesome tuning and parts selection is the key to enjoy this sort of hobby.

Tony the Tiger

The Supra has a very flat boost curve, as seen here on one of my plots posted on my website dyno video section.. I think only 1.5 to 2 PSI of fluctuation which is normal for a car running at this boost:


On the Supra, I've built the engine trying to mimick an S2000 F20C. The intake and exhaust port flow has a ratio just like an F20C. I had some custom chamber work done and shaped it like an F20C and for a fast burn head (following some principles back in the old ENDYN days). Basically, I was morphing my Toyota motor into a Honda but more cylinders to boot...LOL Then moving along to the turbo system, I have an intake manifold that has a efficiency band of around 7000-9000RPM, and my exhaust manifold is double the length of your typical Supra exhaust manifold. It also has a 5" DP and exhaust. Everything counts when building a complete system altogether.

If you are running more boost up top to make the torque flat, you might as well run the boost the whole way across. I only see this as a benefit to help traction, but doesn't quite increase the efficiency and limits of the motor.

When S2000's are turbocharged, they make a flat torque curve with a flat boost curve. Of course, assuming the S2000 has a proper turbo setup. If you cram a log manifold on an F20C and a high flow cat, it isn't going to make anything near a flat torque curve up to 9K

m4xwellmurd3r

I love reading your posts tony, they always have awesome information.

Im trying to do the same with my b18 ls engine. I dont care about power but I want a flat torque curve. It makes the car tamer compared to cars that have a huge torque spike. It looks impressive when the boost kicks in and starts shredding the tires like a mad man, but its not that efficient.

Im just trying to figure out the combination of parts that will give me the best curve. Intake choices suck for ls heads. Its either a stock one or a skunk 2 pro.

Im still debating whether to use a gtx2860r or the gtx2867r. I think the 60 might be better suited for a max power of 380-400hp.

I wish I had the tech knowledge you have for crafting these awesome cars you build.

Schister66

Weaksauce...12" or bust

But on a serious note, I would love to see pictures of your Supra. This may not be the time or place, but that thing sounds intense. The fact that it makes 1100whp more than my STi is simply mind-boggling.

Tony the Tiger

Without VTEC, you are actually going against the odds... Neither of the turbos you've suggested will support 380-400 HP with a flat torque curve on a stock'ish LS in my opinion.

With VTEC motors like a B16 or an ITR, they begin to make flat torque curves with just regular bolt-ons. The factory header, cat, intake/exhaust are the bottle necks that hold them back, but the engine/head/cam combination delivers a flat torque band. By choosing a nice tubular manifold (which acts like a good header), a well matched turbo and big DP/exhaust, it automatically delivers a flat torque curve if the turbo is sized well enough to cover both cam profiles and with balanced intake & exhaust flow across the RPM range. A perfectly matched turbo setup will mirror the N/A powerband, but of course, only after the turbo has spooled up.

On the LS motor, the head/cams is holding it back. With no VTEC, it is a toss up between having midrange or top-end, but not both. It can be done, but much more difficult.

By the time you plan this out, it is far easier to do an LS/VTEC with full ITR valve train, and keep the compression in the high 9's or low 10's. From there, having a flat torque curve is just choosing the right turbo setup

When the engine can make a flat torque curve by itself, you just have to worry about the turbo setup. If torque falls on an engine that usually makes a flat torque after being boosted, there is always a reason why it is falling off. Now with the GTX turbos and many turbine wheel & housing options available, the key is to find out whether it is the compressor or the turbine out of efficiency, a poorly made exhaust manifold, big pressure drop at the intercooler, etc... I can't be typing up a novel, but hope I've covered enough that there are many ways to identify these symptoms (most experienced tuners will know), and there are ways to achieve more flow on both sides (intake & exhaust) without needing to upsize the turbo itself.

Tony the Tiger

I'll sneak in some pics, considering it is already the 3rd page on this thread...LOL All the info on the J-series has already been covered in the first page or so




Engine: (I took off the 12" velocity stack at the turbo on this pic)

ballistic1350

iTrader: (7)

Wow great looking car. Do you prefer wrapping the down pipe to coating it, or is it both?

Tony the Tiger

The DEI titanium wrap wrap works better than the coating, but I have had several occasions that I have used both.

wantboost

iTrader: (2)

yea the DEI stuff is great, only issue I've come across is with their titanium sheet material with the adhesive back

it seems like the adhesive has a much lower temperature threshold than the titanium material. it either cooks itself to whatever surface you apply it to, making removal a total bitch or the material separates from it's adhesive backing.

Flexer

Tony,

If you look at the youtube video you posted you can barely make out the boost gauge and see that it doesn't have a flat boost. You are creeping all the way up to redline. While you didn't do that on your supra, did you do that on purpose on the TL build?

Tony the Tiger

On the video, the boost gauge was in Bar, and the creep was about 2-3 PSI... For this power level, I don't mind it at all and just tuned for it.

The added boost is really no different than trying to do RPM-based boost for traction and help save the driveline, but running more boost up top to get the torque up also lowers the true safe limits on the motor; it is in fact still running more boost. Just stating that out in case we get confused about true flat torque curve and tuning limits discussion earlier in the thread.

Once this engine sees more road time and testing, I can go further to the next level and up the boost more. Judging on some of the numbers I've gathered (from the FA20 example), I should have some more room to play with even on pump gas with this 3.5L

semitas

any updates on this?

Tony the Tiger

The engine ended up cracking a sleeve eventually early this year, so we quickly transferred the crank and rods over to a 3.0L block to make it into a 3.3L motor (smaller bore and thicker sleeve) to minimize downtime. The power was kept at about 620 WHP and compression ratio was 11.5:1 CR.

It's primarily his summer daily / street car, and it also won a few awards at local car shows. He managed to take his buddy with a bolt-on R35 GTR, so yeah, good times
I don't think we'll be pushing more power unless he decides to do a sleeved block, and also beef up his transmission. I haven't got into looking for any transmission upgrades yet, so no idea what's available for it.

Flr Power

Tony, I noticed you went down 1 full CR on the new engine. Is it because it was too difficult to fight detonation with the pump 91-94 octane gas?

To crack a sleeve normally requires repeated exposures to detonation.
Or could it just be that the owner refueled with lower octane gas or he did not used the W/M system to safely guard against fuel variation?