Gibbon's appropriately priced FD RX7

[kpr]

what flange  does your manifold have.    Since rotary's are horribly inefficient  you want something fairly big, on the exhaust side at least.  they spool a big turbo easy and will be easier on the engine with less exhuast manifold pressure.  esp on the crappy fuel up here. 

[xsspeed]

you should probably raise it and fit less dished rims with your small turbo

[gibbon]

24 minutes ago, kpr said:

what flange  does your manifold have.    Since rotary's are horribly inefficient  you want something fairly big, on the exhaust side at least.  they spool a big turbo easy and will be easier on the engine with less exhuast manifold pressure.  esp on the crappy fuel up here. 

yeah I've learned to disregard pretty much any 'rule of thumb' regarding sizing unless it specifically comes from a rotary source. it does seem like big truck turbos are largely ready to bolt-on for a rotary, big diesel turbine housings and all. most of those don't seem to be v-band though. I did read a little spiel which was interesting and put things in perspective, that the major players (BW, Holset etc) produce MILLIONS of turbos that work in arguably more demanding applications than 'performance'. the whole car scene is such a tiny blip on the radar for the major manufacturers that they can't even be bothered to dominate it. so no surprise that when you scratch any high end aftermarket turbo, under the branding you still find a 'dirty old truck turbo'

as for the flange, the absolute largest diameter at the tip of the v-band is 3.5". the "pipe" itself is 3". I am a bit confused as to whether I should be shopping for a 3" or 3.5" v-band inlet as a result

[gibbon]

also do the yanks measure horsepower differently to us or something? guys on the rx7 forums are like "yeah I want something streetable, not too crazy. probably in the 650hp range"

motherfucker have you tried driving a rwd car with 650 horsepower?

 

there was a norwegian guy who made a jibe about importing a US car and "two hundred horses fell off the boat on the way over"

[kpr]

yeah thats pretty big  turbine inlet size. sounds like g40 size  

This one  was a stock engine fd with  6262d pulsar  t4 exhaust housing.   ( basically garrett g35- 900 ripoff)  
nice to drive on the street.  

 

 

 Something like this would likely fit your manifold.  its next size up exhaust wheel  with the same size compressor as the one in dyno graph.    would obviously come on a bit later

 

 

 

[gibbon]

23 minutes ago, kpr said:

yeah thats pretty big  turbine inlet size. sounds like g40 size  

This one  was a stock engine fd with  6262d pulsar  t4 exhaust housing.   ( basically garrett g35- 900 ripoff)  
nice to drive on the street.  

 

 

 Something like this would likely fit your manifold.  its next size up exhaust wheel  with the same size compressor as the one in dyno graph.    would obviously come on a bit later

 

 

 

I liked this guy because he comes with a 90degree compressor outlet and I'm extremely lazy. 300 series, I think its a BW S300 clone, comes in a variety of flavors. and yes the PAC setup i believe was to suit a G42, real big boy territory 

 

 

Here's something you probably don't want to answer: after changing to a single turbo, is it safe to fire up and drive the car to (some poor bastard just south of town) on the existing PFC tune?

 

 

[mjrstar]

2 hours ago, kpr said:

will be easier on the engine with less exhuast manifold pressure.  esp on the crappy fuel up here. 

For sure this, small turbine will have higher egt's and be ripe for sagging apex seals.

[kpr]

2 hours ago, gibbon said:

 

Here's something you probably don't want to answer: after changing to a single turbo, is it safe to fire up and drive the car to (some poor bastard just south of town) on the existing PFC tune?

 

 

Just be careful.   power fc the base map is super aggressive timing wise.  which is a bad day on a rotary.   keep off boost and generally be fine.    Get your hands on a interface box (datalogit or fc hacko) and pull the tune out of the ecu and I can have a look at whats in there 

[gibbon]

I have a datalogit, never used it though... sounds like they can be finicky to set up. Thanks for the offer, I'll see if I can get something out of the PFC

[kpr]

Ive never had that much trouble with them, other than randomly dropping connection and the likes.   should be easy enough to connect and grab the tune.   
datalogit  software isn't that bad to  use considering old tech. same goes for the pfc's themselves.  Old tech and have some quirks  but can still decent results on mild ish  basic setup.  the one in the graph was pfc like every second fd rx7 seems to have 

[Dudley]

1 hour ago, kpr said:

Ive never had that much trouble with them, other than randomly dropping connection and the likes.   should be easy enough to connect and grab the tune.   
datalogit  software isn't that bad to  use considering old tech. same goes for the pfc's themselves.  Old tech and have some quirks  but can still decent results on mild ish  basic setup.  the one in the graph was pfc like every second fd rx7 seems to have 

You heard it here first, @kpr loves a power fc

[SHGWAG]

On 22/09/2025 at 12:50, RUNAMUCK said:

if it does need a rebuild,

While it's apart, it would kinda be rude not to do a full cut Bridgeport, w/ semi PP.  And that big single  @kiwi808 was suggesting too.......

🤣

Yes, do this.

Actually don't, unless you're going to run an 80mm+ turbo. Trust me.

On 24/09/2025 at 18:33, RUNAMUCK said:

I'm sure @SHGWAG once reckoned you could buy a brand new shortblock from Mazda for about 6k? Which is heaps of money. But doritos are not the domain  of the poors.

Plus I watched a video on youtube of some RX8 guys strip a brand new (from mazda) RX8 replacement engine, and point out all the things wrong with it.

Yeah, those days are long gone. Should have kept my spare blocks, would be a rich man now.

On 07/10/2025 at 13:38, Nominal said:

Hit up @SHGWAG for his race rotary?

Dumb thing is, have been thinking of parting out the race car recently, it's sat in the shed for 5 years and gone nowhere.

On 04/11/2025 at 16:26, gibbon said:

also do the yanks measure horsepower differently to us or something? guys on the rx7 forums are like "yeah I want something streetable, not too crazy. probably in the 650hp range"

motherfucker have you tried driving a rwd car with 650 horsepower?

 

there was a norwegian guy who made a jibe about importing a US car and "two hundred horses fell off the boat on the way over"

They also run drag radials on the road too.

650rwhp is the sweet spot, you get traction in gears 3 and up.

 

What a Rollercoaster of a thread!

Good read after being absent from OS for months.

 

Have heard bad things about the large frame pulsar turbos.

My vote is a BW 366sxe, you'll make 300+ wkw on pump gas and 400wkw+ on e85.

1.15? (Might be 1.09) AR T4 exhaust flange.

Relatively cheap turbo as well and have proven reliability.

Go for a stand alone ecu and save yourself from a future rebuild.

 

FDs are a sweet car, I sold my 1st one, soon regretted it and bought another one/two.

 

[shrike]

1 hour ago, SHGWAG said:

Have heard bad things about the large frame pulsar turbos.

In general or specifically on rotaries? 

[gibbon]

Interestingly the rotary builder I spoke to was pretty scathing of most low budget options but gave pulsar turbos the tick

just for the sake of gossip and scandal he was pretty dismissive of PAC performance products

[SHGWAG]

On 20/11/2025 at 17:45, shrike said:

In general or specifically on rotaries? 

Specifically on rotaries, seem to last on piston engines - might be due to the exhaust temps? I know a rotary tuning shop has numerous issues and couldn't even get a refund from them.

 

I've also heard some negative stuff about PAC, but don't run any of their gear.

 

Borg SXEs are good bang for buck, although aren't as responsive as the newer turbos.

I've gone Garrett G40-1200 for my 20B build, should be nice and responsive but will be awhile before I have any feedback.

[yoeddynz]

18 hours ago, SHGWAG said:

my 20B build

Build thread please Mr 

[RUNAMUCK]

Speaking of churbros for doritos,

This just appeared in my feed.

[SHGWAG]

On 25/11/2025 at 11:52, yoeddynz said:

Build thread please Mr 

In the last 4 years I have:

Bought a turbo, wheels, surge tank, lower intake manifold.

That's it.

Would be the longest build thread ever.

 

That 476 wouldn't make power until over 5000rpm and then it would come in like a sledge hammer.

Still think a 300sxe frame is the go.

 

[gibbon]

so the situation continues to deteriorate as I persist in disregarding advice and shedding money.

Firstly I grabbed a top feed rail kit, 1000cc injectors all around, and an ECU manufactured this century

I bought an HKS "special set up kit" which is designed for a HKS GTiii-4R. Then I did some reading and found out (supposedly) that the GTiii-4R is just a Garret 3582 with a coat of makeup. OK I thought, instead of buying the $4k HKS version, I'll save a buck and get the knock-off equivalent. I went with the "compact" version as it had a slightly smaller compressor for the same sized turbine, if I recall

Then the agent calls me and says "are you sure this is what you want? we don't sell many Compacts". I told him the car I had and he upsold me to a 6262 equivalent. I foolishly thought that a T4 was a T4 and that the thing would fit (which in retrospect was extremely naive) anyway, the 6262 fits the T4 flange of course but nothing else lines up. the v-band outlet is the wrong size and is offset differently so the downpipe sits differently and the wastegate joiner pipe won't align with the manifold

the sheer size of it does replenish my mana somewhat, at least

It's not the end of the world. I either modify what I have to make it fit, or bite the bullet and buy the GTiii that the kit was designed around (and there's two different a/r versions available, would they both be interchangeable? or do I need the specific one that the kit was designed around?) or do I take the middle path and go back to a 3582 equivalent and hope that it fits? I kinda don't want to go back to [knock-off brand] as they so handily upsold me to something that doesn't fit, and then weren't interested in taking it back

Bit of a cunt update really as I've done no work and am essentially just showing off spending money on a bunch of mid-to-low range gear. this time of year is an absolute motherfucker for me so I have zero free time and I guess I'm just buying shit for the dopamine rush. hopefully shit will change and I'll find myself holding a spanner instead of a beer

[kpr]

Cut some stuff up.    The 6262 is a ripoff G series  which is newer tech than the HKS thing.   6262 is identical turbo as in the graph i posted up there ^