I sold that setup and am currently going to play with an EFR7670 on a pettit/stock ecu. I loved it though, on 15 lbs it was night and day different from sequential twins as far as power under the curve and on 21-22lbs it was a riot for the street.

 

Is this finally working???
Need to know more details

 

Unfortunately no. It should be running this setup by July or August but it will depend on how long its in the paint shop.

 

Very curious to see where this goes as I'd want something simple like this in the end. I don't sometimes understand the huge horsepower desires on a car that weighs 2700lbs.

 

I'm waiting for a few more parts to come in but this should be up and running by the end of July. As always, it will depend on my work travel schedule.

 

3 years later, as promised, finally a decent tune, the results of my almost identical setup, numbers align pretty well with David's. This was one of our best runs at 15-17psi.

 

So was this a 7670 as well on the dyno chart?

 

EFR 8374 Internal Wastegate.

Stock port
Stock mount intercooler
Quiet exhaust
Moderate boost
Mustang Dyno

Red line is HP
Blue line is TQ

 

Blue knows me so well from across the continent lol. /\ exactly as he said.

 

So getting into boost around 3300 rpm on this one? How much boost and what type of fuel were you running? I'm very torn between the 8374 and the 7670. I don't need a dyno monster but many people recommend the 8374 due to the ability to turn it up later on if needed and the 7670, I guess has its limitations.

 

Go with the 8374, it's a better fit for top end power and still has plenty of torque for running around town and you need less boost to make the same power as the 7670. Dynos don't really show off the best part of the EFR turbos.

 

Some people fight creep on the 8374. I haven't heard similar on 7670.

If you're down to fiddle with it, I think the 8374 is the clear winner.
If you wanna "set-it-and-forget-it" and don't get power lust, the 7670 is a no brainer.

 

No. IIRC, boost was coming on I think around 2500. 15 psi by 3500 maybe? I'd have to ask my tuner to send me the logs. 17-18psi tapering off to about 16. Pump 93 only on that graph. Same basic tune, same boost with water meth was 380-390hp. I was torn between 8374 and 7670 for a year before I got the kit, ultimately chose the 8374 and glad I did, don't think the 7670 would've delivered the power I was looking for. A little faster spool would be nice coming out of corners with a vette or m3/m4 on your tail but it is what it is. Just depends on your needs/goals.

 

Narfle is probably onto something here. Seems like with my 8374, getting that sweet spot with tuning, boost level/control, and AI, is a never ending battle.

 

Well I'm not looking to do water/meth injection and go all crazy with the HP. Personally a 380rwhp RX-7 weighing in around 2600lbs is stupid fast for most circumstances. I've had the highway star cars and ultimately lost love for them because the usable power was always high up in the gear and ... well you run out of road... I quick boosting setup with playful power is ultimately what I want. A single turbo just simplifies an overly complicated sequential system and rids the car of excess heat.

 

I think you made the right decision. You really arent going to see a great response difference with the 7670 unless you are running really high boost. Even then you may only see a 1-300 rpm advantage in the torque curve early on. I'm only going with the 7670 to show how it is a much better current day option for what Mazda accomplished with the stock sequential twins. I'm hoping my theory proves correct and it makes the same or better torque from 2800rpms on at equivalent boost levels. I'm hoping to have a setup on stock fuel and modified stock ecu that runs high 11s.

 

hurry up already! i wanna see what YOU can do on stock fuel, so i can decide what I can do on stock fuel

 

High 11s is still plenty quick. Your goals are very close to my own. I don't have desires to drag race or do anything more than some light track duty and some autocross... mainly want a powerband that can be used on the street as a daily driver.

 

HaHa, I may pull the twins this weekend....it’s been 92-95 degrees every day with the heat index close to or above 100. I’m a little unmotivated so we will see.

 

I am still curious and interested on this endeavour.
Is it moving along?

 

@djseven Any updates on your EFR7670?

 

@djseven happy new year! Any updates?

 

^^you’re 3.5 years and a comprehensive thread read-thru short:

not sure what turbine housing you chose for the 8370, but regardless it will be tighter and more flow restrictive than the 74 housings. Which likely requires higher boost values to achieve the same equivalent top end power outputs he posted in this thread. Turblown was bagging on the results some in the beginning of the thread, but the “comparative” dyno that was posted had been ported, and that in itself is going to matter compared to the OEM stock ports.
.

 

I don't think that's me, I was asking about the endeavorer running the 7670 with Pettit ECU. A comprehensive read-thru would have put that into context.

 

yep, my bad interpretation thinking you were asking relative to your post about the 8370 as per the rest of my comment

but let me help you out some as he never posted anything in this area that I’m aware of

https://www.rx7club.com/3rd-gen-gene.../#post12500372

https://www.rx7club.com/3rd-gen-gene.../#post12500619

https://www.rx7club.com/3rd-generati.../#post12507154

https://www.rx7club.com/3rd-generati.../#post12509843
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