cib24

Something like a T04E or slightly larger.

How did it work?

Did anyone do it with a stock intercooler?

I'm talking about 285-350 whp so within the capabilities of stock twins pushed to 14-15 PSI (I think). Surely a small single making similar power or just slightly more than twins would do fine on a stock intercooler or SMIC?

I ask this because my twins have basically had it. They are eating the abraidable seal and I need to replace them with either a used set of twins or perhaps a small single, but I don't want a V Mout or FMIC. I would prefer everything in the engine bay to remain in its stock location except for perhaps the turbo setup.

Sgtblue

iTrader: (16)

I know of several single set-ups with a SMIC, but not the stock SMIC. It may be due to you pushing out 14 or 15 psi thru the restrictive OEM intercooler that your twins are eating themselves.

cib24

That's cool. So it has been done then? Something like the Blitz or Greddy SMIC perhaps? What kind of power were these people pushing with those intercoolers?

Actually, I'm only pushing 12.5 PSI. Well, that's not true either since I had a boost issue and was limited to 9 PSI for the last 1,000 miles or so. The turbos weren't eating themselves until about 3 days ago as I had everything apart about a week ago and all was still ok (bone dry turbos too at that time).

Either way, the car isn't going to be driven now and is being recovered to my preferred rotary specialist. It's either a used set of twins that goes on or switching over to a small single but retaining the stock intercooler until I can decide on an appropriate SMIC.

By the way, I thought the stock intercooler actually flowed pretty well for moderate power levels? And on a 99 spec car like mine where it is completely separated from the intake system it's even more efficient?

R-R-Rx7

iTrader: (24)

I used the greddy smic with the t78.. not particularly efficient setup but it worked well..

cib24

Great, so an upgraded SMIC like the Greddy with a good duct and my current water injection system should be more than happy enough to run a single.

I need to research singles to figure out what is good for about 325-400 hp (leave a margin of error there) and pulls to at least just over 7k RPM as I use the car primarily for track days and don't want to run out of puff too early on straights. The twins were pretty nice but power noticeably tailed off at around 6,500 RPM although it would rev out to 8,000 if I needed to because of say a shorter straight and it didn't make sense to upshift before the next corner.

Maybe a t04e/s hybrid type thing.

Stock fueling with a direct voltage fuel pump is good for about 350 hp right? So, perhaps 1680 secondaries.

ZoomZoom

iTrader: (2)

I run a GT35R with a M2 large stock mount. Will be running up to 20 psi with water meth injection.
It's done all the time.

ZoomZoom

iTrader: (2)

Spend some time in the single turbo section. Plenty of info for you and your power goals.

cib24

Yes, will do. Thanks!

Montego

iTrader: (1)

GT35R with a SMIC

cib24

Very nice, I love yellow. I was thinking of a smaller smic so I can keep the battery in the stock location.

j9fd3s

iTrader: (3)

^^ i have even seen that setup with an M2 airbox modded to have 1 inlet instead of the 2 for the twins

James2u

iTrader: (5)

I have a EFR 7670 IWG single turbo with a Greddy stock mount intercooler and it was just recently tune on a Dyno Dynomax .

James2u

iTrader: (5)

meant to say Borg Warner EFR and dyno dynamics

jojodotcom

iTrader: (6)

James2u, how many pounds of boost is that? Where can I find more information about your setup? 400whp is my goal one day~

James2u

iTrader: (5)

This tune was 17psi on race gas, but boost bled to 15psi at high RPM. The car was also tune on pump gas 91 octane at 10psi and it achieved 366hp/300ftlbs. Car is built for autocross in Super Street Mod class and weighs about 2570lbs. For more information, I would check out the single turbo section, Borg Warner EFR IWG 7670 post.

Sgtblue

iTrader: (16)

Or PFS Medium. Never dyno'd, a guesstimate by an experienced rotary owner puts it at maybe 275 whp on the original stock twins. Modifications in signature. I've never built the car with a number power goal in mind. But I was able to run side by side with a friend with a stock 1LE Camaro from 40 to 125 mph on a remote highway. His eyes were opened. And I think I can turn better than he can.


I tend to look at it as running 25% over it's design. And the stock intercooler is small and pretty restrictive. With the pressure drop that means that when you were seeing 12.5 psi on your boost gauge (read after the intercooler) the twins were actually pushing, or trying to push, a lot more.

Brekyrself

iTrader: (30)

The smaller SMIC's such as a Greddy, Blitz, and RE-A should not be a problem for a small turbo setup.

The cores are quite a bit larger compared to stock and comparing CFM ratings to similar Bell Intercooler cores, they flow quite a lot for the compact size. Sure end tanks play a part in this but should not be a deal breaker. For comparison sakes, look at a properly sized V-Mount core that ASpec used to make: https://www.rx7club.com/build-thread.../#post12024194

Another benefit of the smaller cores is allowing the radiator to breath. Take a look at a car with the M2, AST, or Pettit Large and the duct almost completely blocks radiator flow through the engine bay.

A smaller SMIC with proper ducting, water injection, and a properly placed intake grabbing ambient air will not be a problem on a small turbo setup.

SA3R

We were using a smaller all alloy SMIC (matches the stock dimensions of the stock SMIC but fabricated in alloy, I think by ARC or similar) which allowed us to keep the factory battery and factory airbox in the stock locations.

We ran non sequential upgraded twins with PFC, fresh engine build, larger injectors, etc and 400hp in Targa Tasmania. You don't need a large intercooler. A smaller but more efficient unit will do the job.

The stock SMIC with its plastic tanks is just 'okay' at stock boost levels. But even in a late model car such as yours where the intercooler duct is not shared by the intake (you must have a JDM Series 7 or Series 8) it is the internal design of the stock core that is inefficient.

Really, the stock SMIC is just a crappy attempt at an air to air heat exchanger, but it was designed to a factory production cost.
The factory SMIC just uses hollow tubes and flat end plates internally. Its not good at cooling the charge because the boost charge comes in the bottom tank and zip! Straight shot thru the very short 5 inch long tubes/core very very quickly with no slow down time to linger and exchange much heat with the alloy core at all. Straight out to the top tank and then on to the engine, still hot.

This is why a lot of the aftermarket SMIC designs use what is called a "double pass" intercooler internal design- the charge enters and has to travel a longer path and stays in the core very slightly longer and has more time to exchange heat with the core and cool down before moving on to the engine.
If you look at say an ARC all-alloy aftermarket SMIC, you'll notice the core is often the same thickness, but ARC sneakily increases the height of the core another 3/8 of an inch at each end (as much as possible between the inlet and outlet pipes). This gives a slightly longer core with longer tubes internally, and more surface area to exchange heat with the boost charge, and the boost charge has to travel through more core, which takes slightly longer, so it is able to shed more heat over time than a stock cooler allows.

cib24

Thank you for the very informative post. I do have a Series 8 JDM car with the separate intercooler duct. Stock boost on my 280PS car is 0.74 bar (10.7 PSI) up from the older 255-265 PS models of 0.62 bar (9 PSI) and technically it uses the same intercooler so it is that much more maxed out. However, my car is now mapped for 0.85 bar (12.3 PSI) which is stressing the intercooler that much more although I am running 250cc/min of water injection to keep the temps in check just in case, although I don't expect to encounter any issues with hot intake temps until the weather gets quite a bit warmer than 12 degrees Celsius (c.50 degrees Fahrenheit) (summer average in the UK is about 75-80 degrees Fahrenheit), as I have done two track days now in sub 50 degree weather and had no problems with intake temps even with the water injection switched off.

I will be upgrading to a SMIC at some point this year but for now my tuner says I am ok running the stock intercooler at my boost levels since 0.85 bar is only 15% higher than the stock level of 0.74 bar for my 280PS model and the Series 8 system is more efficient than the older cars. Albeit, he did say that the water injection kit was a good idea in the interim.

I would like to run something like the Greddy unit and continue using it for when I switch from the twins to a small single (and that might be sooner than later as my twins are a bit leaky) but my current concern with it is that it doesn't fit very nicely with the stock airbox and stock battery tray and cover. And the stock airbox on the Series 8 is well ducted and hard to improve upon unless possibly going for a Knight Sports Air Groove or Autoexe intake system, so I don't want to change it (plus the OEM look is nice in my opinion).

TomU

iTrader: (11)

IMO you can't compare HP and boost numbers between cars that are street driven and cars that are tracked. 20 min+ at WOT is much more stressful and these engines are very heat intolerant. You should keep a close eye on engine heat and IATs. It sounds like you are monitoring IATs and you might be okay with a stock SMIC in your climate (esp w/ AI). However, for peace of mind you should look to upgrade at least to a Greddy or similar SMIC (as mentioned) sooner than later. I trashed my completely stock engine tracking it.

Fritz Flynn

iTrader: (263)

YEP

Even an m2 large gets too hot on track unless coupled with a single turbo, GTC style bumper and great ducting. The only way to keep the twins cool is VMIC or FMIC.

OR just cheat and spray a bunch of water but when your water runs out, a cheap fitting leaks etc.... boom goes the engine LOL

Fritz Flynn

iTrader: (263)

Heat soak is brutal at an autox. I'd go VMIC or FMIC and never look back. Or again go cheap and spray water

Fritz Flynn

iTrader: (263)

Great street setup for 10 to 12 psi

cib24

Agreed and I will be getting the Greddy most likely (thought about the Knight Sports but not sure the dual pass is better than the Greddy setup) and keeping my water injection running at a low 250cc/min just to cool the intake charge rather than use it for anymore power. Once my 99 spec abraidable twins decide to give up the ghost I will probably move to a small single for 350-400 bhp.

Interestingly, the 1999 and 2000 Type RS model (my car basically) in bone stock form won the Best Motoring 20 laps endurance battle in 1999 and came in 2nd in the 30 laps endurance battle in 2000 behind the R34 GTR Spec V, just barely. Water and oil temps were kept in check and it was about middle of the pack on fuel. Lots of other cars like the NSX needed to be kept below redline to keep temps under control.

1999 Test (no subs)



2000 Test (no subs)



So, at least we can say the changes Mazda made to the Series 8 cars with the larger front bumper, revised intercooler and air intake ducting, 2mm larger radiator, bigger oil cooler openings, brake ducting enhancements, etc. made the car reliable for 20-30 laps at Tsukuba in bone stock 280ps form when all of the components were new.

cib24

Love the look of the PFS but it's a no-go for me as I wouldn't be able to retain the stock air box with my twins. The M2 intake there for the PFS are not as good as the stock box and intake ducting on a Series 8 whereby the cold air is directly sourced from the nose of the car via the license plate, and the only thing better on the Series 8 is probably the Knight Sports or Autoexe intakes (with the Knight Sports probably the best and looks more OEM) but they are soooooo pricey!

Knight Sports




Autoexe