RoboticsRacer

I didn't try swapping to a OE style rubber bushing.

FourtyOunce

iTrader: (15)

Great numbers, DJ .... Post the dyno sheet!

GoodfellaFD3S

iTrader: (213)

I'd be curious to see how a nice DJ/Goodfella street port would wake up the high end on this setup......... lose a little low rpm juice but seems like you've got enough to give

500 rwhp with a killer powerband would be the bee's knees IMO

Congrats homeboy

Monkman33

iTrader: (28)

Is that what we need to rename my engine's port job?

R-R-Rx7

iTrader: (24)

Sounds very similar to my setup David... and i have been extremely happy with the overall behavior of the car.. main difference is that im running 29psi and a full 3.5inch exhaust.. i have full boost by 3200rpm and the car wont go straight in forth gear. I kept stock intake ports and ported the exhaust only..

Good job man. Congrats

Moe Greene

iTrader: (2)

Mad props man, I love that you kept stock port! Also nice to see someone keep the stock port while making serious power.

Ernstudet22

iTrader: (4)

Steve Khan turned my car almost two and a half years ago. It was on 93 pump gas and AI. I had very good results. I'm using the 8374 with internal wastegate and completely stock ports; untouched. At the time I had problems with Boost creep and ignition breakup at high RPM. I was able to get 480hp with 377 tq on its 2nd pull. Steve finalized at 475hp. This was on a motor that had 105 PSI on all the faces. Since then I've upgraded the entire ignition system. Ported the wastegate so I no longer have Boost creep. Rebuilt the engine and threw away those garbage are ra classic seals that were hard on my housings. Im pushing 115+psi on all faces now and no longer have ignition breakup. I'm confident that I'm getting well above 500 now. The 8374 and stock ports go together like peant butter and jelly. Lol

rotaryfreak3

Nice, what boost level are those numbers at?

BLUE TII

iTrader: (9)

The boost trace is the faint dotted lines starting under the AFR traces and using the same scale #s.

Boost peaks at 10-11psi boost at 2,750rpm which holds to 4,000rpm where it starts to creep to 26psi by 6,750rpm.

RGHTBrainDesign

Great observation, Blue!

Based on the power output, I'd suspect turbine housing was undersized AND exhaust undersized for this particular 2.5yr old setup. That's a lot of EMAP and creep.

Ernstudet22

iTrader: (4)

Sirlaughsalot, could you explain your statement about the exhaust? It was my understanding that a larger, less restrictive exhaust contributes to boost creep. I don' understand how a smaller, more restrictive could do the same? Thanks

Darryl C

What did you upgrade your ignition to if you don't mind please. Cheers

Ernstudet22

iTrader: (4)

Darryl, I upgraded to the smart coils. I mounted them where the a/c pump used to reside. That enabled me to make very short custom wires. I'm using the $40 each NGK plugs. I can' t remember the number off the top of my head. Elliott sells them. I'm pushing about 24psi on 93 octane and I dump roughly 20% water/meth in.

cib24

Resurrecting this thread but I'm on the fence about a 8374 right now, but when I compare this chart I'm not so sure it's worth the £5-7k to do the swap, upgrade the intercooler and fueling, etc.

Note, both dynos are in the UK and converted to crank horsepower with 15% drivetrain loss correction as that's the norm for how they display power here. Also, our dynos are usually less optimistic than US dynos.

Both cars on stock ports, 3" exhausts and 15 PSI.

First chart is twins with a stock air box, Greddy SMIC, water injection and 3" Knight Sports twin tube downpipe, 3"with high flow cat and 2.75" cat-back.

Second chart is 8374 EWG twin gates manifold to 3" downpipe, 3" mid pipe to RB cat-back.

Converted to wheel horsepower and 15% drivetrain loss the twins car makes 340 whp at 6000 RPM and 300 lb ft. by 3200 RPM, and holds that torque (aside from the sequential dip) to 6000 RPM.

By contrast the 8374 at the same 15 PSI makes similar torque of 300 lb ft by 6000 RPM but at 3200 RPM where the twins made 300 lb ft the 8374 is only making 230 lb ft. It makes power longer though and tops out at 380whp at 7400 RPM.

Obviously, we all know the 8374 can make much more power and typically only starts making good power when you get above 20 PSI as it likes boost, but I thought this was a very interesting comparison between two similarly spec'd cars minus the different turbos.

Twins at 15 PSI, stock ports, 3" exhaust


EFR 8374 at 15 PSI, stock ports, 3" exhaust

BLUE TII

iTrader: (9)

Were these both done on the same brand and model dyno?

I ask because different dynos load the car differently and so will show different low rpm power/spool.

I noticed that dynoing my same car/turbo on Dyna Pack hub dyno, Dynojet and Dyno Dynamics roller dynos.

newtgomez

Those are some interesting dyno numbers. On the twins side of things, it doesn't seem very feasible that the first turbo alone makes more torque than the engine makes total bhp. The EFR dyno on the other hand does seem very realistic as far as numbers go. I've seen a lot of people making 400whp around 14psi (Right where the turbo starts to really shine). It's also good to keep in mind the twins made 340bhp versus the EFR making 440bhp at similar boost levels. The EFR genuinely feels like a v8 in the lower gears and has excellent mid range and a desirable wide power band. If you want more, smoother power, you definitely won't look back after doing the single conversion. The turbo is absolutely insane for a street car and not to mention, makes maintenance a lot easier with no more rats nest business going on lol.

cib24

The twins Dyno doesn't show the car making more torque than hp. The crank horsepower is 398 while the peak torque is 360. In wheel horsepower and torque terms that is 340 wheel horsepower and 300 lb ft.

Also, in crank horsepower terms the EFR made 443hp to the twins 398. Converted to wheel horsepower that is 380 vs. 340.

I don't disagree at all that the EFR is the better setup and has more potential. I was simply challenging the post I originally quoted that the twins can't make good power and torque compared to the EFR at 15 PSI. To me, the evidence suggests at that boost level with similar setups the EFR is worth 50 extra hp on the top end for £5-7k, so if you have healthy twins run them until you have issues or need to rebuild the motor before splurging on a EFR kit?

silverTRD

iTrader: (36)

That twins dyno does seem optimistic to me as well. I would just suggest going for a ride in someone's car similar to what you're looking to do and see how you like it. It really is the best way to know if that's what you want though not always feasible. To be honest I don't trust dyno's posted by a majority of shops, hell I don't even know if the dyno I was given is truly accurate. I just know my car is a blast to drive. My .02

knotsonice

iTrader: (2)

You also need to look at longevity. The twins at those power levels won't last. It's well documented on the site. I had 99 twins (running 350hp at the wheels) for about 3 years and then went the 8374 route. Honestly i love the twins, but the 8374 is awesome, power band is huge and have almost instant response.

dguy

iTrader: (8)

@cib24

Twins running that hard will be fun but they're not going to last, myself and acquaintances have nuked far too many (even upgraded) to have that even be a question. If you'd like to build a car that's on the knife edge of failure go for it, the EFR offers a synergistic solution to the 400+ horsepower goal while keeping lively spool. To me that's worth 8k, maybe not to you.

cib24

Well, I ran my used twins for 20,000 miles at 1.0 bar before they started letting oil through, and that included 5 or 6 track days per year over 3.5 years. Rebuilding them costs about £450 which seems like a decent price to service them every 3 years.

But of course, I totally get your point about the benefits of the 8374. My initial post was merely to point out that the twins do quite well against a 8374 if both are limited to 1.0 bar, stock ports and a 3" exhaust.
​​​​​

Narfle

iTrader: (16)

As others have pointed out, the twins are dead-men-walking at medium-frame-turbo power levels. Any results to the contrary are born of heroic effort.

KYPREO

To my mind, there's little point running around with a 8374 at only 15psi. It is a modern turbo designed to remain efficient at higher boost levels. I recall E85 is possibly not readily available in the UK, but this is where water injection comes in.

Also, 3" downpipe and cat will hold back the EFR from spooling down low as well as inhibiting top end power. 3.5"-4" is likely to perform much better, particular on an internal waste gate setup. The whole system doesn't need to be that large, but the size of the first few feet is very important for maintaining exhaust gas velocity.

djseven

iTrader: (56)

That stock twin torque curve is not close to reality. No one is making 300ftlbs on the primary turbo on 15lbs. Im not sure anyone has ever hit 300ftlbs on the primary turbo honestly at any boost level.

cloud9

iTrader: (4)

@djseven You still happy with the setup? Anything you would do different to alter driveability or exactly what you wanted?