I've been contemplating on the engine / turbo setup for roads like "Tail of the dragon" and "Angel Crest Hwy", basically tight medium speed winding roads with lots of 2nd, 3rd gear turns.

I am currently running stock port engine with stock twins at 14-15psi and it feels very good; I wonder if anyone has thoughts and or experience on making it even better with another engine/turbo configuration.

I have Ohlin DFV, STOPTECH BBK and nice sticky tires ... so running gear is good.

Looking for something a fast spooling, a little more low end tq and not necessary more HP.

Or am I looking at this all wrong and I should focus on weight reduction to increase enjoyment?

I have a 93 touring and have taken out the BOSE snake, installed RZ Recaros, 2 piece rotors, 17inch light weight RS wheels, titanium midpipe and catback ......

Next weight reduction step is probably with a Antigravity ATX-30D to replace my current AGM battery.

Thoughts?

 

Stock is best. If you want more power then you can raise the boost some or get a different final drive to change the driving experience. Stock twins are going to be your best set up for this. An efr would likely do very well also but the cost vs what you're going for wouldn't make much sense. Stick with optimizing the twins. Go bnr if anything

 

For those roads you don't need/want big power. Twins and response are the way to go.

I have 99 twins and they can dig me out of a corner on the Dragon like crazy. I leave the car in 3rd all the way through the dragon, typically pulling out of a corner at 2200-2500 RPM and it digs in and goes.

If anything maybe look at the 99 twins, they have a lot better response. I also got the 4:44 RX-8 ring and pinion, that improves response big time as well.

Dale

 

Thanks for the responses, much appreciated.
I do have a set of old school BNR stage 3 sitting at home.

I’ll throw that in and see how it goes.
i just didn’t want to do thru swapping twins if there are better options.

thx!

 

S2 RX-8 4.77:1 differential gear swap will help whatever engine/turbo you decide on.
FD has some long gears and you can get caught up between them on slow corners.

I had EFR 7670 on my FC and it is very comparable to the stock twins in my FD without the sequential quirks.

The EFR 7670 has potential for lots more torque than twins if you do decide to turn the boost up.

If you decide you want the simplicity of a single turbo I would go EFR 7670.

 

How does the increased tq from shorter gear or EFR fair on medium to low traction surfaces?

The set up makes sense on race track or nice pavements.

There is some times sand, gravel and other liquid/debris on the ground that makes it less than ideal.

 

If you are worried about gravel and road debris, stay stock and drive carefully. There are other types of stock cars with 500hp and way more torque than the FD that go canyon carving, just drive within your limits.

 

stock ports and stock twins are fine. Focus on keeping them well maintained and healthy.

 

Well, in my experience your front tires are going to hit the sand and gravel before the rear tires when driving your vehicle using the forward gears so sand and gravel are most likely going to make you understeer off the outside of the turn before it has a chance to get under the rear tire.

Im being serious and speaking from my experiences.

I put my car in plenty of ditches.
"Ditches love cars, so I gave that ditch a car." Is a saying with my group.

Now I mainly race sanctioned events.
Our autox venue is an old WWII diragible airport in the sand dunes and we been racing on it unimproved. Lots of gravel and sand there.

 

The EFR 7670 was easy to modulate traction with for its HP. Much easier than my old T04B 60-1 turbo that made 40hp less and 100ftlbs less tq.

I think this was because of a couple reasons.

1) 7670 was very responsive and has the recirculating BOV back into the compressor anti-surge housing. You let off the gas a little and you dont lose all your boost and also, boost comes back right away.

So, your not doing the old flat foot steer through the wheelpspin driving like with a laggy turbo.

2) I had the boost cranked up with race gas so it was 420ftlbs tq and 420hp Dynojet. The fact that tq was equal to hp means torque took a **** at 5,000rpm. So, when the tires start to spin and engine rpms shoot up- torque dies off and its easier to modulate wheelspin.

But your point about increasing hp or tq not really helping in the curves is a valid point.
I had an auto RX-8 on Ohlins and the 18x11 295/30-18 DotRs from my FD and it would **** on the FD on a road where you cant use the gas and brakes. It just has higher cornering mph and you dont really care if it ends up in a ditch either (but, its an RX8, so it never did).

have you considered getting an RX-8 for the canyons?

 

EFR 7670 is the ultimate replacement/upgrade for twins. It comes on fast and linear so you don't get the huge torque surge a modified twin turbo car can exhibit when the second turbo comes on which can put you into a wall. If you want more top end go with a 8374.

 

Well he says hes just looking for a little more low end torque. The cost of going with an efr in pursuit of "a little more low end torque" isn't the assignment lol. Turbo, manifold, downpipe, intercooler, charge piping, fueling, ecu, tune.... imagine spending all that and all you needed to do was change your gearing 😕😕. Sounds like hes happy with the twins but just wants a little more on the bottom end.

 

good luck trying to find the s2 rx8 4.77:1. they are long gone and whoever has one they sell them for an arm and a leg. for what the OP is describing the 4.44 sounds superb as suggested by Dale.

 

Still available new. RS08-27-110A. its not cheap, but none of the ring and pinion sets are
actually Mazda USA has a ton of the whole assembly, RS08-27-100H, might be a better option, you'd need to swap it into the FD carrier (iron housing), but you'd get new bearings, gears, and the fancy back cover

 

I think the 4.77:1 would be overkill for a street car. You'd be cruising on the highway at some ridiculous RPM. That would only make sense for a dedicated track car.

The 4.44's are in the sweet spot - they improve response but the car is still very street able. I get 22-23 mpg highway driving to Deal's Gap every year.

This also isn't the most crazy life-changing upgrade - you do it, the car seems more "eager" and can pull out at lower RPM's easier, that's about it. It's not like adding 50hp or something.

RX-8 diffs should be a dime a dozen, but parts for RX-8's are kind of weird now. Some of the parts people want a fortune for them and they aren't moving. RX-8's are dying off VERY quickly and I think a lot of them have been going to the scrap heap as-is, not even getting parted out.

Dale

 

i have a 4.7 in my car and its as dale describes. ~4k at ~75mph is kind of annoying on the highway. i stay within a 30mi or so radius of its parking spot whenever i drive it so its never for very long but cruising is limited by rpm and i think that concept is wild. im sure i COULD cruise at a higher speed but sitting at 5k+ while doing it, im not interested

 

a lot of websites claim that are in stock until its time to order. mazda was supposed to reproduce them. i dont know if they did.

i ended up buying a complete pumpkin from an R3 Rx8 to get the ring and pinion. not only they are expensive, they are hard to find

 

i was running 4.44 until very recently and for a street application IMHO it is superb. highway was comfortable enough and acceleration was great. i have now switched to a 4.77 now but my setup now is a little more track focused. i have built 2 identical pumpkins with the only difference the ring and pinion. if the 4.77 is annoying i will switch back to the 4.44 that i absolutely loved

 

I did find someone selling a 4.77 from a S2 RX8 for $480, looks like it might be a poor fit from being too short.

S1 RX8 diff can still be found readily available for $150-$200.

I somewhat want to go EFR 7670, but only if I can run it with a Petitt ECU. I am waiting for DJ to confirm, but I think he lost motivation.

 

You can't... you'll need a standalone. Primarily for the reason of having to run substantially larger injectors and to compensate for the incredible increase in air mass to the engine.

 

imo a 6-spd would make more sense than a 4.777, but obviously a bigger investment

surprised this latest NissanZ/CD009 conversion hasn’t come up on the forum yet, been out for 4 or 5 months now


which they also offer the trans and diff mounts for the ppf delete as well

https://www.fischracingtech.com/prod...adapter-system

requires using a Z based flywheel/clutch though is the only thing I consider a downside on it, offset by the dedicated cast bellhousing I suppose.
.

 

FD will be the only car for fun right now until I can upgrade to a newer better car.

New transmission and/or turbo is good ... but it seems like it's low ROI

Weight reduction might be the way to go.

 

faster =/= more fun, two different things

um Mazda would do the all of the above, if you can drop a little weight, add a little power (either hp, or gearing, at the wheels), and improve the suspension, you can make a big net difference

 

This thread was about engine/turbo for tight winding road. I went into gearing as its related to power delivery.

If we are going into chassis set-up...

the biggest improvement in performance for tight widing roads/tracks (to the car) and also one of the most cost effective is wheels and tires.

I run 18x11 +45 wheels front and back with 285-305 wide DOT race tires.

Word of caution, higher cornering speeds mean wrecking at increased speeds as well.

Just having fun and performance be damned has its merits. *cough Miata*

 

Wheels and tires are the first things I've optimized.
After multiple sets of rims and tires, I've settled on 18x10, 18x9 BBS LMs with 275 and 255 Firehawk Oval 500 tires.

Works great at a wide range of weather/temperature, enough traction going straight but can get loose in the corners and still have that "dancing" feeling in my hands.

As is sits



friends I’ve met on my midnight run