Fritz Flynn

iTrader: (263)

Those setups both look better than the PFS setup. What are your plans for the car?

Chronumn

iTrader: (2)

I have said set up, will be selling the box shortly

cib24

I'm honestly more than happy with the stock airbox with the twins but my airbox is falling to pieces (it was given to me for free) so I've been looking at the Knight Sports and Autoexe options. The Knight Sports kit looks more OEM and also maintains a seal down to the front bumper behind the license plate duct whereas the Autoexe is open at the top and that doesn't make a lot of sense to me as it kind of messes up the vaccum effect the airbox and air guide are supposed to have sucking in from the duct at the nose of the car (but it's a minor point although I also don't like the carbon fiber look as a personal taste preference).

Anyway, either kit could most likely be converted to working with a low mounted single that keeps the stock air pump (gotta pass emissions!) if you look at this photo and how the kit would connect to the twins:




At the moment I'm having the twins diagnosed (to confirm they are destroying themselves and also see why I'm stuck at 8-9 PSI when the secondary comes on as opposed to 12.3 PSI) and also shortly thereafter installing the IR Performance baffled filler neck so that I can curb my oil surge issues in right hand turns as oil is flying up the filler neck and coating my entire intake system with fresh 10w-40. Assuming the twins are fine then I will keep the car as is and upgrade the intercooler and replace the airbox over time and continue enjoying it on the track and improving my driving. The car is already quicker than everything on track barring little Caterhams, R35s, other super cars and higher powered Porsches.

96fd3s

If you want to spend the money, you will not be disappointed by a properly sized single.
Why do you want to stay with a SMIC?
If going single, sticking with a SMIC & moving the battery should be the least of your worries.

cib24

Well, quite simply I refuse to relocate the battery or remove the A/C, cut up any part of the engine bay, or relocate any wiring so a V-Mount or FMIC are definitely a no-go. I do not want to give up the car's creature comforts as it is my only car, and whilst it is my occasional weekend toy that sees the track 10-12 times per year (no need to have a car for living in London during the week), it is also used for holiday trips throughout the UK and continental Europe (hoping to do a trip to Spa this year and the Nurburgring the next). In fact, my wife and I very recently did a trip to Snowdonia (North Wales) and drove c.1,000 miles all-in over a 5 day period which included a track day at the start at the gorgeous Anglesey circuit, all whilst averaging 23mpg for the trip (and not exactly driving slow), enjoying the occassional A/C, the comfort of the Ohlins in full soft for putting around the mountains (and so my wife wouldn't kill me), etc.

I wish to retain that flexibility and storage space for trips like that so a SMIC will have to do and is why I also did water injection to make up for anything a SMIC lacks.

96fd3s

Yea you cant have everything and have it be ideal. SMIC will work, but its not ideal no matter how you justify it. You can compromise and move your battery and have a bigger intercooler, or you can compromise and run a smaller intercooler that wont cool as well.

Like it or not, you need to compromise somewhere. Weather its with the cooling (for bigger or for smaller), the battery location, the size of the turbo or stay with the twins. You cant have it all. Well you can with loads of money.

Hey, anything is possible with enough money though. I gather that you are not/will not be doing the work yourself which makes going single for a reasonable price much more difficult.

Sounds to me like staying with the twins is the best option for you

edit; and why do you care about moving any wiring but dont care about taking the turbo's off, strapping on a new manifold, turbo, wastegate setup, fuel system, and ECU? FYI you can do a complete single conversion and keep ALL of the stock harness intact.
The only thing you would need to change is the MAP sensor plug if you got a different MAP sensor, and maybe the IAT sensor plug, however you could probably find an adapter for both if you cant solder or are that afraid to alter anything from original.

Topolino

iTrader: (2)

Here's an option to consider (see attached link). I'm soon to be upgrading my '99 Spec twins to an EFR8374 so a smaller turbo will definitely be good with this SMIC. These guys (Rotary Performance) are well-respected on here so feel free to give Chris Ott a call to discuss your plans. He won't steer you wrong.

Rotary Performance - New Intercooler for your 1993-1995 Mazda RX-7

Note: Like others have alluded, plenty of good info within the Single Turbo threads, too.

Brekyrself

iTrader: (30)

I have not seen any actual math or cfm ratings for the SMIC's mentioned. We can however do some estimation by eliminating variables such as end tank design.

RE-A SMIC
12x8x4

Looking at Bell Intercooler cores, which they show CFM @10psi I am told, can give us an estimate of what the RE-A SMIC can flow in CFM.

They have 3.5" and 4.5" thick cores so lets take an average of the two.

Bell 12x8x3.5 @10psi shows 794cfm
Bell 12x8x4.5 @10psi shows 1021cfm

So without actual testing we can assume the RE-A core (without endtanks) will flow around 900cfm @ 10psi.

Smaller SMIC's also have an advantage of not blocking the entire radiator exit such as the M2/Pettit Larger models. Better throttle response. Will bolt into a stock twins setup and based on the numbers should be just fine in a lower flow single setup with proper ducting.

For reference I have done track events with stock twins @ 12psi with the stock intercooler! Yes it will heatsoak and lose some power. Did it blow up? No. I also plan on trying the RE-A SMIC with an EFR 8374 setup logging IAT's etc... on a track.

Some simple searches turn up good intercooler info.
https://www.rx7club.com/single-turbo...er-one-887021/
https://www.rx7club.com/single-turbo...e-help-875582/
https://www.rx7club.com/single-turbo...zero-r-472529/

Sad some of the old school members and shops such as ASpec(Zero R) are not around. They did actual math.

cib24

Of course a SMIC is a compromise but so is a V-Mount or FMIC because you need to do significant modifications in the engine bay and potentially lose good things like A/C. In my case:

1. I want to keep convenience for street use and road trips as I don't really need more than stock power to put around on public roads (so many speed cameras in the UK that there is not much opportunity to put your foot down and straight line highway pulls are kind of boring and more dangerous over here because highways aren't really straight like the I-10 in the US).
   
2. 300-400 hp FDs are more than a handful on track, extremely exciting, and quicker than 95% of the cars you will ever see on track anyway. Besides, 75% or more of the speed of a car on track is down to the driver and I know I couldn't handle the peakiness of a FD with more power than that.
   

Perhaps a bit of a tangent here but I honestly don't understand why the default recommendation for everyone with a FD seems to be to convert to a V-Mount or FMIC when 95% of the cars are just street cars and people whom drive at WOT on public roads are usually doing it on the highway or back roads where the car is moving at a decent pace and thus the SMIC is not heatsoaked and is cooling just fine.

But anyway, you are probably right that twins are the right (or cheapest) choice for me long-term but I worry about spending the time and money to remove and replace them with used units that inevitably start smoking or failing again in a short period because all twins (except brand spanking new ones) are 15-25 years old with decent mileage on them, and thus potentially having to spend the money to do it a 2nd or 3rd time when I could have converted to a single.

Also, swapping to a small single doesn't really seem that complicated if you buy a kit already setup like a genuine HKS T04S kit or the Rotary Performance GT35R kit, which I just discovered, both which basically come with everything you need (and they both work with an air pump which is great). And complete kits pop up used all the time as another option.

Rotary Performance GT3582R Single Turbo Kit

From what I understand, if looking to make a max of 400hp a hotwired fuel pump, 1680cc secondaries, adjustable fuel pressure regulator and a tune is all that is really required on top of the turbo kit itself. Not sure I would need a different map sensor with either turbo? Stock one is good for about 17 PSI if I recall, and I already have a fast reacting IAT installed to help the PFC react quickly to IAT changes.

cib24

Thanks for that. Their GT35R kit looks really good as well and keeps the stock air pump. I have sent them an email asking for more details on the SMIC and the kit.