Custom Big Single Turbo To Custom Twin (S55) Turbo upgrade

[wheela]

How was the response and spool of the BW8474, thinking about swapping my G35-900 (T4 TS) for it. I'm on fullboost at 4000 RPM (24 PSI).
Maybe you can share a log?

Try comparing the EFR 8374 and EFR 8474 in Borg Warner's matchbot using some of your log data. I was deciding between these two turbos, and for a 3 liter engine the 8374 actually seemed like a better match. It had a better surge line (a couple psi more boost earlier on), and seemed to stay in the meat of the efficiency islands better.

At least with the numbers I entered, it seemed like with the 8474, the engine's psi to flow ratio kept the operating points below the 8474's peak efficiency range on the compressor map. So for my numbers, it was predicting better boost response, AND better average efficiency with the 8374 than 8474. In fact, it didn't predict better estimated compressor efficiency with the 8474 until 7000 rpm. Seems like 8474 might be better for a slighlty larger engine that can move more air per psi than our 3 liters can.

That said, my entered numbers were just my own best estimates, so it could have been crap in crap out, lol. But still worth looking at.

Here's my 8374 data from matchbot

 

[wheela]

And some 8474 data for comparison. It can't hit as much boost as soon, and is mostly operating below it's optimum efficiency range.

 

[BloodyZ4]

Yeah I've played with the Matchbot before, I'm either planning on building the engine and staying with the G35-900 (flows only 80lbs, so more like a 800hp turbo) or switching to the 8474 and come closer to 950HP (my Matchbot 8474 calculations).
I just wanted some real world data from @Dumaurier7, to compare it to my current setup, I hope that the GammaTi wheel will improve spool and response or at least be the same as the G35-900, don't wanna upgrade to the G40-1150 which would be even lazier...

 

[wheela]

Yeah I've played with the Matchbot before, I'm either planning on building the engine and staying with the G35-900 (flows only 80lbs, so more like a 800hp turbo) or switching to the 8474 and come closer to 950HP (my Matchbot 8474 calculations).
I just wanted some real world data from @Dumaurier7, to compare it to my current setup, I hope that the GammaTi wheel will improve spool and response or at least be the same as the G35-900, don't wanna upgrade to the G40-1150 which would be even lazier...

Dang, 40 psi is no joke

 

[Dumaurier7]

Yeah I've played with the Matchbot before, I'm either planning on building the engine and staying with the G35-900 (flows only 80lbs, so more like a 800hp turbo) or switching to the 8474 and come closer to 950HP (my Matchbot 8474 calculations).
I just wanted some real world data from @Dumaurier7, to compare it to my current setup, I hope that the GammaTi wheel will improve spool and response or at least be the same as the G35-900, don't wanna upgrade to the G40-1150 which would be even lazier...

Sorry, I've been swamped at work and at home! here you go, https://datazap.me/u/dumaurier7/log-1716811616?log=0&data=2-3-4-16

 

[BloodyZ4]

No worries man, you got maybe a log with a 3rd gear pull from like 2500 or 3000 rpm, so I can compare it to my G35-900 ? This one is low gears, so hard to compare.

Dang, 40 psi is no joke

Yeah, will be on a built engine if I decide to keep the car and not switch to B58 Z4, still unsure, I do prefer the E89 design but that B58 is a piece of art
Also boost should come down with the built head, I guess something like 32 PSI if my assumed VE is right -> Matchbot built head
Love playing with the matchbot

 

[wheela]

No worries man, you got maybe a log with a 3rd gear pull from like 2500 or 3000 rpm, so I can compare it to my G35-900 ? This one is low gears, so hard to compare.


Yeah, will be on a built engine if I decide to keep the car and not switch to B58 Z4, still unsure, I do prefer the E89 design but that B58 is a piece of art
Also boost should come down with the built head, I guess something like 32 PSI if my assumed VE is right -> Matchbot built head
Love playing with the matchbot

Matchbot is the best! Remember to update the compressor efficiency row with values from the compressor map. Unfortunately. This row doesn't automatically adjust to the compressor map, and updating these values will require you to readjust your expansion ratios to get the turbine map matched up. This will affect the numbers predicted by the tool.

 

[BloodyZ4]

Good point! It was also mentioned in the BW videos I think, but I totally forgot about it
Updated Matchbot

 

[island road]

I'm actually deciding on these two turbos at the given moment both with EWG T4 1.05AR. Ideally I would like the smaller AR but not sure if I really want to go IWG. The 8474 is very popular with 4N motorsports and a lot of B58 / S55 guys atm. Spool is going to be around 200/250 sooner with the 8374.

Not to mention SX-E cover swap. As an example of this when testing an on an 2012 STI The SXE cover reaches full boost (around 20-21 psi) by 4,000 rpm, while the EFR 7163 standard cover takes until around 4,500 rpm to reach the same boost level.

That being said I think the sweet spot would be EFR 8374 with SX-E Cover and T4 1.05AR. They don't make the SX-E cover for the 8474 but there is one company machining the one for the 8374 to fit the 8474.

SX-E Style Cover for EFR Testing

 

[wheela]

I'm actually deciding on these two turbos at the given moment both with EWG T4 1.05AR. Ideally I would like the smaller AR but not sure if I really want to go IWG. The 8474 is very popular with 4N motorsports and a lot of B58 / S55 guys atm. Spool is going to be around 200/250 sooner with the 8374.

Not to mention SX-E cover swap. As an example of this when testing an on an 2012 STI The SXE cover reaches full boost (around 20-21 psi) by 4,000 rpm, while the EFR 7163 standard cover takes until around 4,500 rpm to reach the same boost level.

That being said I think the sweet spot would be EFR 8374 with SX-E Cover and T4 1.05AR. They don't make the SX-E cover for the 8474 but there is one company machining the one for the 8374 to fit the 8474.

SX-E Style Cover for EFR Testing

That's an intersting video But that was with a 7163 which comes without an anti-surge inlet on the cover. Look how small the inlet is on the 7163 vs. the SX-E style cover with the anti-surge inlet. I bet they had to increase the ID of all the inlet piping just to fit the OD of that larger anti-surge inlet. I'm sure the larger inlet on the compressor helped, but I bet a good chunk of the gains were also from the larger inlet piping they must have used.

I suspect these gains may not be there when switching to sx-e style covers on the larger EFR's like the 8374 and 8474 that already come with 4" anti-surge inlets. Unless the a/r's are different? It would be cool if somebody did a comparison on one of these to confirm.

 

[wheela]

I'm actually deciding on these two turbos at the given moment both with EWG T4 1.05AR. Ideally I would like the smaller AR but not sure if I really want to go IWG. The 8474 is very popular with 4N motorsports and a lot of B58 / S55 guys atm. Spool is going to be around 200/250 sooner with the 8374.

Not to mention SX-E cover swap. As an example of this when testing an on an 2012 STI The SXE cover reaches full boost (around 20-21 psi) by 4,000 rpm, while the EFR 7163 standard cover takes until around 4,500 rpm to reach the same boost level.

That being said I think the sweet spot would be EFR 8374 with SX-E Cover and T4 1.05AR. They don't make the SX-E cover for the 8474 but there is one company machining the one for the 8374 to fit the 8474.

SX-E Style Cover for EFR Testing

Are you gonna be running an n53 head?

 

[island road]

That's an intersting video But that was with a 7163 which comes without an anti-surge inlet on the cover. Look how small the inlet is on the 7163 vs. the SX-E style cover with the anti-surge inlet. I bet they had to increase the ID of all the inlet piping just to fit the OD of that larger anti-surge inlet. I'm sure the larger inlet on the compressor helped, but I bet a good chunk of the gains were also from the larger inlet piping they must have used.

I suspect these gains may not be there when switching to sx-e style covers on the larger EFR's like the 8374 and 8474 that already come with 4" anti-surge inlets. Unless the a/r's are different? It would be cool if somebody did a comparison on one of these to confirm.

Your absolutely right, BW made the SX-E for the early style EFR turbos and the returns are slightly less on the larger frame turbos. BW does not make the cover for the 8474 so i doubt the shop that machines the cover to fit "Turbokits.com" is really not worth the $450 cost. As for the 8374 there are gains to be had but yes smaller. Although still curious to so see what they would be, the covers are fairly cheap "Around $200".

I will be buying within a week here so would like to nail down exactly what I am going with. I know sure its T4 Divided and EWG. I love the EFR series although I don't love the fact u cant rebuild them. After talking with 4N Motorsport "He uses the 8474 on all his kits" has said they perform amazing but the G series might spool a tad better but the response can't be matched. I think where the EFR 8474 really shines is the higher RPM would benefit from.

Are you gonna be running an n53 head?

At this point I'm trying to get this kit finished so I don't think I will be going that direction. I am in the process of my shop doing a custom kit for my car and nobody that I know of makes a turbo flanges for N53 that you can buy online.

 

[wheela]

Your absolutely right, BW made the SX-E for the early style EFR turbos and the returns are slightly less on the larger frame turbos. BW does not make the cover for the 8474 so i doubt the shop that machines the cover to fit "Turbokits.com" is really not worth the $450 cost. As for the 8374 there are gains to be had but yes smaller. Although still curious to so see what they would be, the covers are fairly cheap "Around $200".

I will be buying within a week here so would like to nail down exactly what I am going with. I know sure its T4 Divided and EWG. I love the EFR series although I don't love the fact u cant rebuild them. After talking with 4N Motorsport "He uses the 8474 on all his kits" has said they perform amazing but the G series might spool a tad better but the response can't be matched. I think where the EFR 8474 really shines is the higher RPM would benefit from.


At this point I'm trying to get this kit finished so I don't think I will be going that direction. I am in the process of my shop doing a custom kit for my car and nobody that I know of makes a turbo flanges for N53 that you can buy online.

Let us know what you go with! If you do 8374, do you think you'll try both compressor covers? I went with 8374, butbI plan on using the recirculation valve, but I'm still interested to see if any gains could be had with the sx-e cover

 

[island road]

Let us know what you go with! If you do 8374, do you think you'll try both compressor covers? I went with 8374, butbI plan on using the recirculation valve, but I'm still interested to see if any gains could be had with the sx-e cover

Will do! What AR did u go with?

If I do go with the 8374 I will try the se-x cover.

 

[wheela]

Will do! What AR did u go with?

If I do go with the 8374 I will try the se-x cover.

Sweet! I did the 1.05 AR external wastegate version. I'll be running a Turbosmart Hypergate 45 wastegate.

 

[BloodyZ4]

After talking with 4N Motorsport "He uses the 8474 on all his kits" has said they perform amazing but the G series might spool a tad better but the response can't be matched. I think where the EFR 8474 really shines is the higher RPM would benefit from.

Guess I might stick to my G35-900 then I thought the BW might spool faster.
I have 10PSI by 3500RPM and 21PSI by 4000RPM right now. It just hits hard, it's not that linear, guess the BW would be better in that.
Response on the G is also really good if you keep the revs up, but that's easy with the DCT.
Also here's the plot I had made for my G35-900 if anyone is interested:

 

[wheela]

Guess I might stick to my G35-900 then I thought the BW might spool faster.
I have 10PSI by 3500RPM and 21PSI by 4000RPM right now. It just hits hard, it's not that linear, guess the BW would be better in that.
Response on the G is also really good if you keep the revs up, but that's easy with the DCT.
Also here's the plot I had made for my G35-900 if anyone is interested:
View attachment 95750

That's what's better about the 8374 vs. 8474, the surge line is better so it can spool earlier. In trying to target 20psi, matchbot predicts the 8374 can hit 16psi by 3000rpm. Quick spool and super-responsive.

Granted it's only a 79 lb/min. turbo vs. 80 lb/min for the g35-900, but look at the relatively broad range of pressure ratios you can hit 79 lbs with on the 8374. Plus it's turbine is bigger, so you may end up with less back pressure at high rpm, which means you may get more hp per pound of boost

I haven't driven either one though, so this is really just my own assessment based on my tinkering with matchbot

 

[island road]

Are you gonna be running an n53 head?

I was not planning on it but then confirmed a few more things with Omar after seeing his video today and literally just pulled the trigger. It's being sent from Germany but advised it will be here possibly on friday maybe monday. Complete with Cams, Ledages, all hardware ect. I am going to use the stock internals for now. My shop thats building my manifold will be doing the conversion work.

We already have a 3D scanner so it will be scanned so we can get it into Cad and build out a Flange. More than likely I will be putting these flanges on my site for anybody that wants to do the same project as this product does not yet exists to buy off the shelf.

With that it seems I will be going with the EFR 8474 1.05 AR. I decided to do EWG incase I wanted to swap turbos down the road. With the efficiency of N53 head Omar mentions spool is about 250-300 RPM sooner. That's about the difference between the 8374 vs 8474 with the added headroom of the 8474.

Guess I might stick to my G35-900 then I thought the BW might spool faster.
I have 10PSI by 3500RPM and 21PSI by 4000RPM right now. It just hits hard, it's not that linear, guess the BW would be better in that.
Response on the G is also really good if you keep the revs up, but that's easy with the DCT.
Also here's the plot I had made for my G35-900 if anyone is interested:

From my research this past few weeks on the Garret G Series and EFR Turbos trying to decide between the two I have seen a few race teams mention the 6 + 6 blade design allows a soft build up of boost pressure. This allows more driving through the feel of pedal in relation to the power you are going to get aka more linear as you mentioned.

 

[Dumaurier7]

So I finally received the turbos a couple days ago! First impressions? Top notch work, the quality is there, I have no complaints. Investigations reveal porting of the OEM turbo fold and a new larger compressor housing and of course, larger internals and the ball bearing center. Based on what I see it looks like a GT3071R that they modified to fit in the OEM structures.

 

[Dumaurier7]

The size increase of the compressor housing is evident as the coolant lines do not drop in fit anymore, a small bit of tweaking of the aluminum lines with just enough allowance from the rubber hose sections (BMW brilliance again) makes it easy. In order to properly support the changes, they also include an intake kit (similar to MAD) and boost pipes as the ones for standard turbos will not fit, if anyone is interested have a pair of ARM pipes for the OEM hit me up if interested.