Turbo Questions

[Crackerjack17]

Had a procharger for around 20k miles. No issues, enjoyed it. Power was definitely towards the top obviously. Around 10 psi, 93 octane.

I now have the hellion sleeper with precision gen2 bb 64/66's. Have about 1k miles on this combo. I'm still on wastegate and 93oct at about 8ish psi (7psi spring). Wow what a difference even with lower boost than the procharger. The torque down low is impressive if you give it enough gas to get to zero vacuum and close the blow-off valves. I don't know what others are talking about lag. With the turbos I have it is freaking instant boost. Sure If I'm in 5th gear and 1500 rpm and give it gas, there isn't much air moving to spool them and it takes a second. BUT, hold it at 3k and lay into it and bam! Instantly the wastgates open and it is making more psi than it can use.

What maintenance? The whole kit is just a bunch of tubes and turbo hanging. I ran one line from oil pressure sender to turbos and then out of turbo to drain and scavenge pump.

It is a lot of stuff to hook up and get right, compared to simply bolting on a Whipple or tvs. But once it's hooked up, I think it's simple. I like to work on cars, so for me it was fun.

I love it so far. Waiting on some fittings and time to finish hooking up the boost controller. I'm using all motion raceworks push to connect vacuum fittings at the turbos and wasgates, etc. No leaks.

My biggest problem is trying to figure out what tire and size rim to run once I dump the E85 in it and turn up the boost!

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[Cordero1]

My only issue with turbo kits nowadays is the pricing. +$10k + the fuel system & most don't even include the manifolds. That's just wrong. Best turbo kit option is what gimmie11's did & build the kit yourself.

 

[Cory S]

I don't know what others are talking about lag. With the turbos I have it is freaking instant boost.

No you don't. Apparently you don't know what "Instant boost" is. 64/66's still lag like a MOFO. Period.

I won numerous races against 6466's to 140mph because of the lag they had. Same owners always claimed little to "NO LAG".

 

[Crackerjack17]

No you don't. Apparently you don't know what "Instant boost" is. 64/66's still lag like a MOFO. Period.

I won numerous races against 6466's to 140mph because of the lag they had. Same owners always claimed little to "NO LAG".

Yeah, you prob right. It feels like instant hit, but riding in my friends c7z with 800 wheel, that thing hits hard, now. I haven't raced him yet so will see. I guess I meant people thinking you have to count to 2 before boost hits.

 

[Cory S]

Yeah, you prob right. It feels like instant hit, but riding in my friends c7z with 800 wheel, that thing hits hard, now. I haven't raced him yet so will see. I guess I meant people thinking you have to count to 2 before boost hits.

Exactly. There’s always going to be some lag. Some way more than others, but mitigating it the quickest way is key. On the street anyway.

 

[Slopoke]

Where do you want the torque kick to come in, down low or later in the RPM range? If it's down low, a roots type supercharger, Whipple, Roush, Edelbrock, is for you. If you want it to come in later, a turbo or Paxton type supercharger is it. I have turbo experience and was disappointed in some turbo upgrade choices I made. Sure the last turbo I installed on one of my previous cars made a bunch more HP, but the down low torque kick was now a lot later in the RPM range. Buy once cry once.

 

[engineermike]

I see it posted often that certain power adders “drive like stock until you floor it”. Maybe I’m in the minority but that’s not what I want. If I doubled the power, then I want double the low-end torque and response as well, so it can be enjoyed under normal driving conditions that don’t necessarily include wot at 7000 rpm.

I’d like the throttle pedal to act as a rheostat, with linear torque response from the engine. If you say you want to drive like stock at part throttle then you’re reserving the large power increase the the last half of the pedal, which makes it nonlinear and harder to modulate.

 

[andrewtac]

Well it is sort of true with a centri. If I don't mash on the throttle the bov stays open, but even part throttle it does make boost. Low end torque does increase, but not as much as the other SCs. It isn't instant, but is somewhat linear in that it comes on around 3k and keeps building in a linear fashion. I can drive it like stock if I am easy on the throttle, but get on it an it goes.

It is linear with a step function.

 

[Crackerjack17]

I see it posted often that certain power adders “drive like stock until you floor it”. Maybe I’m in the minority but that’s not what I want. If I doubled the power, then I want double the low-end torque and response as well, so it can be enjoyed under normal driving conditions that don’t necessarily include wot at 7000 rpm.

I’d like the throttle pedal to act as a rheostat, with linear torque response from the engine. If you say you want to drive like stock at part throttle then you’re reserving the large power increase the the last half of the pedal, which makes it nonlinear and harder to modulate.

My BMW has the B58 inline 6cyl single turbo and that thing makes 3-4 psi barely above idle(according to the onboard power gauge it has) And has a lot of torque down low.

The mustang on the other hand, doesn't apply much boost if any until the blow off valves shut.

I guess the bmw has carefully matched turbo, intake and cams? Plus small little turbos that spool quick down low.

 

[engineermike]

I have no direct experience with the b58 but I know the ecoboost does a lot of trickery with the throttle blade, bypass valve, and wastegate in the name of reducing spool time and better controlling boost. I’d be surprised if the b58 didn’t. With gdi and a modern ecm, there are lots of knobs and dials that can help spool. The mustang controls for an aftermarket turbo are more traditional for obvious reasons, so largely not capable of that level of control.

 

[Biggness]

I appreciate all the replies. Certainly enjoy learning more about it all.

One question that was sparked by some comments with turbos’ power delivery:

Would its power be easier on the rotational driveline components compared to a pd blower? If the torque isn’t instant, then the rotational shear force seems like it would less?

 

[engineermike]

The funny thing is that you can program in a slower throttle response if you want to be easier on the driveline….but nobody ever does.

 

[Angrey]

I see it posted often that certain power adders “drive like stock until you floor it”. Maybe I’m in the minority but that’s not what I want. If I doubled the power, then I want double the low-end torque and response as well, so it can be enjoyed under normal driving conditions that don’t necessarily include wot at 7000 rpm.

I’d like the throttle pedal to act as a rheostat, with linear torque response from the engine. If you say you want to drive like stock at part throttle then you’re reserving the large power increase the the last half of the pedal, which makes it nonlinear and harder to modulate.

I recently installed a smoothboost and that's exactly what it seeks to create. Rather than a binary (closed/open) affair for the BOV or Bypass, it gradually opens/closes the valve according to throttle position. The result at WOT is the same with or without it, but off throttle conditions are much smoother. Some of this can and is handled with calibration/tune to feather throttle input vs blade position, but when you start getting into very large throttle bodies and/or very aggressive blower setups (small pulleys for big boost) the ability for the tune to handle the mechanical limitations of a vacuum operated valve start to fade. The SB makes it MUCH MUCH easier to modulate the power and output of the car with your right foot.

Turbos obviously can do this with sophisticated wastegate control, but only at RPM's at or above where the turbines create positive boost pressure. The bottom end still drives very pedestrian (which is what some people want).

The SB can be ramped differently (rather than 1:1 with APPS) but I haven't really delved into that. It also allows for a scramble and cut features as well (although I'm not messing around with the scramble simply because it creates a potential scenario where the throttle could be closed and the bypass closed and the blower still spinning and making sauce and end up damaging something).

What I like is that under full WOT, it behaves the same way it normally would, but just cleans up and smooths out the off throttle to be much more linear. It's not cheap, but so far it's definitely worth it, my setup is pretty extreme and the vacuum/boost flipping so violently made the whole driving experience much more racecar/unrefined than I wanted.

 

[illtal]

No you don't. Apparently you don't know what "Instant boost" is. 64/66's still lag like a MOFO. Period.

I won numerous races against 6466's to 140mph because of the lag they had. Same owners always claimed little to "NO LAG".

They starting in the wrong gear/RPM

 

[illtal]

I recently installed a smoothboost and that's exactly what it seeks to create. Rather than a binary (closed/open) affair for the BOV or Bypass, it gradually opens/closes the valve according to throttle position. The result at WOT is the same with or without it, but off throttle conditions are much smoother. Some of this can and is handled with calibration/tune to feather throttle input vs blade position, but when you start getting into very large throttle bodies and/or very aggressive blower setups (small pulleys for big boost) the ability for the tune to handle the mechanical limitations of a vacuum operated valve start to fade. The SB makes it MUCH MUCH easier to modulate the power and output of the car with your right foot.

Turbos obviously can do this with sophisticated wastegate control, but only at RPM's at or above where the turbines create positive boost pressure. The bottom end still drives very pedestrian (which is what some people want).

The SB can be ramped differently (rather than 1:1 with APPS) but I haven't really delved into that. It also allows for a scramble and cut features as well (although I'm not messing around with the scramble simply because it creates a potential scenario where the throttle could be closed and the bypass closed and the blower still spinning and making sauce and end up damaging something).

What I like is that under full WOT, it behaves the same way it normally would, but just cleans up and smooths out the off throttle to be much more linear. It's not cheap, but so far it's definitely worth it, my setup is pretty extreme and the vacuum/boost flipping so violently made the whole driving experience much more racecar/unrefined than I wanted.

Can you show us how that is done (what it looks like under the hood with the electronic bypass)? I looked at this solution a while back and decided against it.

BTW - Most twin turbo setups are oversized, and/or wrong AR this is why they lose short races.

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