FI tuning on AT, questions.

[Tim86 24]

Hi all, long time lurker here. I've owned my '86 for two years now and warranty is up soon, so 'it's time' so to speak . I've been compiling a list of modifications for my project and had a few basic questions.

First off, i currently have 4x 57C6 18x9.5 wrapped in Yokohama 105's for the street and set of MeisterR ZetaCRD+, so i'm pretty much covered for extra tyre, brakes to come.

I have an AT, so hopefully won't be needing transmission mods for 300 whp?

I'm looking at AVO turbo Stage 3 Billet from fensport with the following support mods:

3 bar map sensor, Electronic boost control via Ecutek, Avo Turboworld Race Breather System, Forge Dumpvalve, Mishimoto Thermostat, Heat Wrap, spark plugs, Ecutek Map and License.

1) Will i need an oil cooler & gauge?

2) Is 300whp achievable on the stock 2.5" exhaust system if i buy a front pipe w/high flow second cat? is 3" 'absolutely necessary'? 

3) If i went HKS v3 SC instead of turbo, bar the manifold (which i already have) what _necessary_ support mods am i looking at? Again, with a 300whp target.

4) If i track the car on the Turbo setup during british summertime am i likely to run into heat issues regardless of the support mods mentioned? I see loads of this from turbo users on usa forums but that's factoring in the Cali heat. I'd probably only track two or three times a year but don't want to be having to wait for temps to cool frequently.

Thanks

 

 

[GT86-Ian 351]

This thread might give you some useful  information.

 

[Tim86 24]

33 minutes ago, GT86-Ian said:

This thread might give you some useful  information.

 

Good read, thanks. Actually i was looking at the TD kit recently due to the price of entry, but i do like the more OEM style of the AVO Billet. Cosworth is most definitely out of my bracket.

Not much information on supporting mods, but looks like an oil cooler is a must for track. Could potentially get away without before i do track it..

This is my first venture into FI and i'm by no means a veteran, so if anyone else could chime in on my q's with my whp target in mind that'd be great.

[S18 RSG 429]

If Cosworth is out of your budget, so is a safe 300whp.

You can achieve 300whp with the items you've mentioned, but without upgrading internals, you're at huge risk of blowing the engine, in which case, you're talking about doubling your investment.

I'm interested in why you think 300whp is necessary. Mike's stage 2 tune on his demo car is running 340 at the fly, and it's on the limit of what's safe on the stock engine thanks to his tuning, but to me, it's maybe a little too much for the road.

I would suggest 300hp at the crank is all you'd ever need on the road. Sure, on the track you can go higher still, but for 2-3 track days a year, it's not really a track car. 

There's a good reason most FI owners stay at around 280hp. It's safe on the engine, requires no supporting mods beyond off the shelf kits, and puts the car into Cayman S/M3 territory anyway.

[Tim86 24]

4 minutes ago, S18 RSG said:

If Cosworth is out of your budget, so is a safe 300whp.

You can achieve 300whp with the items you've mentioned, but without upgrading internals, you're at huge risk of blowing the engine, in which case, you're talking about doubling your investment.

I'm interested in why you think 300whp is necessary. Mike's stage 2 tune on his demo car is running 340 at the fly, and it's on the limit of what's safe on the stock engine thanks to his tuning, but to me, it's maybe a little too much for the road.

I would suggest 300hp at the crank is all you'd ever need on the road. Sure, on the track you can go higher still, but for 2-3 track days a year, it's not really a track car. 

There's a good reason most FI owners stay at around 280hp. It's safe on the engine, requires no supporting mods beyond off the shelf kits, and puts the car into Cayman S/M3 territory anyway.

I respect that, i'm just interested in going slightly above the norm. Sure, i probably wont off the bat, but 90% sure ill be doing so within 12 months.

My budget isn't necessarily limited and granted i probably worded it wrong, but the price of entry for the cosworth kit is not justifiable for me.

At the moment it's AVO stage 3 vs TD vs HKS v3.

Would anyone care to enlighten me on questions 2) and 3) in particular?

[Steeps 294]

Wouldn't want to be putting more than 280bhp at the crank through the autobox, it's made of cheese. The Cosworth kit mapped to 2.3 is what they have tested is safe for the engine without it becoming a lottery on the rods, the gearbox will not handle any more power. Speak to Fensport about the autobox because they have a lot of experience trying to put power through it for one customer with the Avo turbo kit.

[Tim86 24]

29 minutes ago, Steeps said:

Wouldn't want to be putting more than 280bhp at the crank through the autobox, it's made of cheese. The Cosworth kit mapped to 2.3 is what they have tested is safe for the engine without it becoming a lottery on the rods, the gearbox will not handle any more power. Speak to Fensport about the autobox because they have a lot of experience trying to put power through it for one customer with the Avo turbo kit.

Thanks, well i saw a few threads on ft86 and assumed otherwise, hope somebody can clear this up, as it would infinitely suck if that's the case. I'd definitely be after more than 280 at the crank in the long run.

I can dig threads up if needed, basically saying the AT is good to withstand around 350whp. Also, according to the thread below, there's a solution to cooling the AT trans, but a lil expensive:

http://www.ft86club.com/forums/showthread.php?t=51851

Would love to see a tuning shop chime in on this thread and spread wisdom.

[Steeps 294]

Might be worth having a read of this:

For road use you're probably fine putting the power through it, but going near track it's going to cook the box.

 

[Tim86 24]

1 hour ago, Steeps said:

Might be worth having a read of this:

For road use you're probably fine putting the power through it, but going near track it's going to cook the box.

 

Thanks, that's a great read!

Can somebody please confirm how relevant the following statement is from the above thread:

"Point to note 240 hub in a s.c is no where as hard on your motor and transmission as a turbo. Its the torque that will cook your trans. A s.c brings linear power (more you squeeze more you get). A turbo hits hard mid range with everything."

If the above is true then looks like i'll be going HKS v3, and then the next step will be to decide what an 'acceptable' target would be for track use. Looks like i'll also have to restrict myself to shorter bursts on track days to be safe.

What makes things worse is that they are mentioning in that thread that a 4.67FD brings more heat/very bad for AT with FI. The MFactory 4.67FD is actually an essential on my build list !!!

Someone care to chime in on the above? A realistic maximum output for non-modded AT on HKS v3 (if less risky than turbo) with a 4.67FD for casual track use.

Thanks

 

 

[Lauren 2259]

Well, it's the torque that that the auto box can't handle, though the rule of thumb is around 260bhp flywheel for the auto box, though you may get away with 280bhp. So in this respect an SC is a bit kinder on it than a turbo. You could though have a tune with a turbo that basically de-tunes it compared to what you would do on a manual I guess. But really you're well on the limit of the auto box at that power. The gearbox over heating is an issue. You will be going through the gears quicker with a shorter final drive, so I can sort of see what they are saying in respect of more heat. 

Keith (Special K) had huge problems with his auto when he was trying to go over 300bhp, he eventually gave up and is going for a Cossie SC, after spending huge amounts trying to sort out the problems with the gearbox. It's a shame because the manual has no issue it seems with high power outputs. 

[Kodename47 446]

57 minutes ago, Lauren said:

It's a shame because the manual has no issue it seems with high power outputs. 

That's relative as reports are that around 300-350lb.ft (350-400whp is mentioned alot) the manual box starts being an issue too. Admittedly that's double the torque of the standard car but the manual isn't a strong box either.

As the OP is a AT driver it is worth mentioning that 300whp is more bhp than the manual, you're shooting for more like 350-360bhp at the flywheel. You're well into needing a built engine territory and even a fully de-restricted HKS SC will struggle to hit that. You could go for a Sprintex 335 or maybe one of the larger Rotrex blowers with a HBP fitted. The easy option would be turbo but factor in beefing up the motor once you're past 250whp on whatever you do.

[S18 RSG 429]

To answer your questions 2 and 3:

2) I'm almost certain that level of power is attainable with a 2.5" exhaust. Plenty of tests revolving around this subject on the internet, not just in GT86's. Most test seem to conclude that a 3" exhaust only really makes a big difference when you get into 500bhp+ territory. Sure, you'll probably see a few extra hp even around 300, but if you already have 2.5" system, there's little point in upgrading.

3) Supporting mods for a safe 300whp and a HKS charger would almost certainly include uprated internals (pistons and rods as a minimum). An uprated clutch, brakes, minimum 255 wide rear tyres (most recommend 265's for this power) and an oil cooler would be the starting point. Factor in £4.8k for HKS kit and fitting (Fensport prices), £3.5-4k for the uprated internals plus labour, £500-1k for clutch and labour and even if you ignore the parts not related to the engine, you're in for close to £10k already.

I also completely forgot you have the auto box, instead of manual, in which case, you're going to really struggle going anywhere above the norm. Learn from Keith's mistakes, as he spent a hell of a lot of time and money finding out what you can now know for free. In the end, I think your best bet would be to pick the kit you want (I would recommend TD's turbo for obvious reasons), install a 4.67FD to more closely match the manual box, then if you want some extra speed, add lightness rather than power.

As a final side note, don't necessarily pay attention to those who say a supercharger is "kinder to the engine" than a turbo. That's all to do with the map. I would actually argue that a turbo application can be tuned to be even kinder than a supercharger, as you have full control over boost pressure by adjusting the wastegate. A supercharger makes boost as the engine builds revs, and you adjust boost by fitting smaller pulleys/belts, so the boost is much less flexible than with a turbo. Just something to think about.

[ThatGuyThere 54]

I've read a lot around this recently, and the accepted rule is 280bhp is safe with stock internals, any more than that and you need to open the engine up, or cross your fingers.

So the best route would be to aim for that, as your stage one, and then save up for rods etc. - most superchargers and turbos are capable of much more, so a re-tune would then give you what you wanted easily.

You might find some people saying more than 280bhp is fine - but I'd trust Cosworth, and their testing/experience, over random posts online.

Can't comment on the auto box though ::shudder::

[KevinA 695]

280 is crank BHP if your looking for 300 WHP there is no way on Auto and stock internals. 

[Lauren 2259]

I've driven the Sprintex, HKS and two or three AVO turbos one of them which was an auto. Of the two AVO turbos one was a 280bhp the other one was a 'stage 3' with over 300bhp (though without a rolling road it's anyone's guess) , which was guesstimated at 330bhp, though I suspect it was less. I found the delivery of the 280bhp stage one car far preferable over the stage 3. It just became all about the power which just dominated the experience. If you're a straight line junkie it's great I guess. 

Of the SC options the Sprintex seems to offer a load of low down torque but run out of enthusiasm at the top end. The HKS was far, far better for me at least as it really flies at the top end. This is where the fun is. 

So I wouldn't be too worried about getting over 300bhp, 280bhp is plenty IME. 

[Kodename47 446]

4 hours ago, S18 RSG said:

A supercharger makes boost as the engine builds revs, and you adjust boost by fitting smaller pulleys/belts, so the boost is much less flexible than with a turbo. Just something to think about.

You've heard about variable valve timing right?

[Ade 517]

If you want 300WHP on the Abbey Motorsport hub dyno, the cosworth/harrop makes around 270 hup hp with a decent exhaust. If I were you i'd get either of those and be happy. 270 vs 300whps is 11% and will save you a built engine, clutch, injectors, pump  and other things.

If you are feeling lucky you can fit a smaller pulley and take a risk on the rods. 

 

[S18 RSG 429]

1 hour ago, knightryder said:

You've heard about variable valve timing right?

That's not something you gain with a supercharger though, as it's available on both applications, so not really sure why I would mention it?

[Tim86 24]

Thanks for all the informative comments on this, needless to say i'm now in a more educated position than i was.

So here's where i'm at.. Thanks to Keith's efforts we know i'm limited to how much power i can achieve without chewing through my gearbox (although still unsure on ball-park figures). This leaves me to thinking that i could take advantage of this situation, potentially going another route with my approach, which would be bang-for-buck.

After sitting down with a calculator, and from what i can see, even with a few added support mods to this package there's simply no other option that can compete with the Stage 1 TD kit. Combine this with the fact that i have a brand new HKS EL manifold to sell if i go turbo over SC, this option almost becomes a no-brainer on paper.

This leaves me with the following questions moving forward.

1) The TD kit is most likely going to be 270-280 at the crank. How safe is this bearing in mind the 4.67FD?

2) With 30 minute intervals on the track in mind, let's entertain the theory that the SC route would be easier on the gearbox, how would this translate to numbers? Maximum safe potential at the crank? I guess that's like asking how long a piece of string is, but i can't help but ponder. For instance, if it turns out i really couldn't run more than 240 on Turbo, but could run 280 on the SC, well, i'd probably spend the extra for the HKS v3.

3) Uprating my thermals and cooling elsewhere: If we believe that less heat under the hood might help the AT during track use, would this have any significant effect in negating heat levels inside the gearbox? I'm sceptical if it would make much difference TBH, we could be talking a 1% difference as this is not addressing the root of the issue. Probably better off with a dedicated solution for cooling the trans only...but I'm no expert on heat dissipation.

 

 

 

[S18 RSG 429]

Ok, so the reason people are saying supercharger is easier on the gearbox isn't for anything that relates to you being able to run more power. The engines are weakest at low RPM. Supercharging is a good method to avoid big lumps of low down torque, as the boost builds with RPM (faster the engine spins, faster the supercharger pulley spins), so by design, it avoids early spikes in torque.

Turbochargers, by design, deliver all their boost at the point of the boost threshold (where the compressor wheel is spinning fast enough to make boost in basic terms), this means you go from making 150lb/ft of torque, to suddenly making 100lb/ft extra as soon as boost kicks in. However, this is a very basic outlook on the system, and also more accurately describes old school turbos as opposed to the modern systems, like TD's.

One look at the dyno chart of the TD kit shows you that this kit isn't like that. Mike tunes his kits in such a way that the boost builds gradually, and is therefore very smooth, possibly as close to a supercharger as you could hope to achieve from a large turbo. 

Your power ceiling will be the same on either a supercharged application or a turbo, the difference comes in torque and power delivery. A well tuned turbo application will be every bit as safe as a supercharger. The statements you've heard likely refer to the fact that, inherently, a supercharger is safer due to its design. It requires less human input (tuning) to limit low down torque than a turbo. That means 270-280 from the TD kit should be fine, as I'm sure Mike will test the hell out of the gearbox limits when he's tuning it to make sure it's safe.

I honestly couldn't give you a solution to cooling the gearbox. I don't know if there's a method or package out there to cool the gearbox fluid or whatever, but maybe drop Keith a PM on here, he might have came across something during his experiments.

[Kodename47 446]

1 hour ago, S18 RSG said:

That's not something you gain with a supercharger though, as it's available on both applications, so not really sure why I would mention it?

Because it means you can control cylinder pressures. By increasing valve overlap you can blow boost out the exhaust ports, reducing the effective boost. A wastegate isn't your only option to reduce pressure, so it's not just a turbo that can "tune boost".

[Tim86 24]

On 3/17/2017 at 3:54 PM, S18 RSG said:

The engines are weakest at low RPM. Supercharging is a good method to avoid big lumps of low down torque, as the boost builds with RPM (faster the engine spins, faster the supercharger pulley spins), so by design, it avoids early spikes in torque.

Your power ceiling will be the same on either a supercharged application or a turbo

S18, thanks so much for such an informative post. There were simply huge flaws in my thinking, even though i understood the basic difference in fundamentals between SC and Turbo, i wasn't applying that correctly to my method of thought, really shows that this is my first time venturing outside of NA

So in an ideal world i'm looking for as linear response as i can, avoiding spikes. With this particular kit it's the peak at 4k that will be my trans biggest enemy.

Granted, a supercharger will be better in this respect, but if the tune is good then is that really an issue? Bearing in mind the price difference is considerable still between both options. 

To re-iterate, i want to be able to track the car for 30mins at a time. Guess i will have to buy oil cooling for this closer to the time :/

TL;DR

Q's

So my power ceiling will be the same on both? Interesting to hear opinions on what that will be for my desired application?

I would appreciate if anybody else could chime in with thoughts on HKS v3 SC vs TD Stage 1, if i'm planning to squeeze the most from my application then what is safely achievable?

[Kodename47 446]

If you're planning on tracking for 30 mins a go, you'll need an oil cooler. FI or not. That is quite long for a session.

Over here it's the HKS V2 you'll find for sale, I believe the V3 was just for the US market.

[Deacon 1357]

Your big weak point is the auto box - I'm not sure if you need an auto box but if not if your long term plans are bigger power it may be more financially sensible to swap to a manual?

[Tim86 24]

5 minutes ago, knightryder said:

If you're planning on tracking for 30 mins a go, you'll need an oil cooler. FI or not. That is quite long for a session.

Over here it's the HKS V2 you'll find for sale, I believe the V3 was just for the US market.

1) I'll probably ship over a jackson racing oil cooler or similar.

2) I could easily freight forward an HKS v3 if i'm going to benefit from that.