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Discussion Starter · #1 ·
I'm first on the waiting list for a Sky Red Line here in San Diego, but I'm trying to overcome my aversion to turbocharged cars. Ever since the Porsche Turbo and Saab Turbo hit the market in the '70's, I've fixated on the problems inherent with turbo lag. Yes, I love the top-end rush when the turbocharger has spooled up and the huge horsepower kicks in, but on those early cars, there was a definite absence of power when the revs were low. This was due to the engine's compression having been reduced from the standard, non-turbocharged motor, so that when the turbo reached full boost it wouldn't blow it up.

Do you think turbo lag has been sufficiently reduced in modern turbocharged engines so as not to be a problem anymore ? Is it noticeable at all (the lag, not the extra power) ? Has anyone here owned an older generation turbo-charged car, and then also owned (or driven) a modern day turbo, that can address whether turbo lag has been exorcised from today's cars ? Thanks!

 

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I have driven modern turbos and they still have lag. You can twin turbos help since one is tuned for low end and the other for top end, or in the case of Bugatti you get 4 turbos! The twin scroll turbos are supposed to help but there is still lag below 2500-3000RPM. Personally I prefer a supercharger to a turbo as they are virtually lag free when tuned correctly. They just feel more meaty for that low end grunt.
 

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Discussion Starter · #3 ·
krazygoat said:
I have driven modern turbos and they still have lag. You can twin turbos help since one is tuned for low end and the other for top end, or in the case of Bugatti you get 4 turbos! The twin scroll turbos are supposed to help but there is still lag below 2500-3000RPM. Personally I prefer a supercharger to a turbo as they are virtually lag free when tuned correctly. They just feel more meaty for that low end grunt.
Thanks for the feedback. I've also heard that the dual-turbo approach works well to overcome turbo lag, but the single turbo in the Sky Red Line is the much more common approach, of course. Thus my concern. Thx.
 

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Yes most all tuber charged cars are going to have lag until you have the turbo spooled up. Most all turbo charged engines have turbo lag up to the 2500 to 3000 rpm range thats why when shifting a turbo charged car you need to keep the revs up and the turbo spinning good. To keep the turbo spinning good it is required but not needed to have a blow off valve or external wast gate. Only way to solve this problem is with more turbos or NOS 25 shot works good to get the revs up fast off the line but who in there right mind would want to spray a new car.

I have 2 Conquest TSi/ Starion TSi 2.6L inter-cooled turbo charged cars. There way more work then a natural aspirated engine and yes there fun to drive but I'm sticking to the 2.4L ecotech over the 2.0L ecotech turbo. I would like to work with just striate up HP this time around love the work they have done with just the ECU and CAI.
 

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If you read anything about this engine along with the turbo, as well as look at the dyno graphs, you'll see that there is virtually no turbo lag.

I have a 95 talon tsi awd, which I consider to be very old and in stock form, the turbo usually kicks in in the mid 2k rpms and attains full boost around 3k. The new evos attain thier full boost (around 20psi) much later (3600rpms or so) and depending on who you talk to, that isn't a considerable amount of turbo lag either.

The cure to turbo lag is the ability to downshift. You shouldn't be trying to accellerate in a higher gear anyway, you will just be putting more load on the engine and slowing yourself down opposed to where if you can shift into a desireable area of your power band, you'll have much better accelleration as well as put less strain on the engine.
 

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There is a hp/tq curve posted on the GXP forum. They have done the impossible, the car puts out 260 ft-lbs from 1000 rpm all the way to 5000 rpm. It is unlike any dyno curve I have ever seen, it must be accomplished via variable valve timing and the direct injection. If I didn't know better it is almost like a nitrous graph as it relates to the torque, but, a little flatter and longer.

I ordered a mean GXP last week. I will dyno the car as soon as it is broken in and post the curves.
 

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Jack B said:
There is a hp/tq curve posted on the GXP forum. They have done the impossible, the car puts out 260 ft-lbs from 1000 rpm all the way to 5000 rpm. It is unlike any dyno curve I have ever seen, it must be accomplished via variable valve timing and the direct injection. If I didn't know better it is almost like a nitrous graph as it relates to the torque, but, a little flatter and longer.

I ordered a mean GXP last week. I will dyno the car as soon as it is broken in and post the curves.
Just to clarify the torque is 260 ft-lbs from 2500 RPM and up, and is 250 flt-lbs from 1500 RPM to 2500 RPM. Still very impressive for a first revision, small displacement engine. I bet over time you'll see more power from future revisions as well as Stag kit upgrades.
 

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brentil said:
Just to clarify the torque is 260 ft-lbs from 2500 RPM and up, and is 250 flt-lbs from 1500 RPM to 2500 RPM. Still very impressive for a first revision, small displacement engine. I bet over time you'll see more power from future revisions as well as Stag kit upgrades.
Gotta love those Stag upgrades :D :willy:

Stag 2 here I come!:thumbs:
 

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tvieira24 said:
Gotta love those Stag upgrades :D :willy:

Stag 2 here I come!:thumbs:
I unfortunately do not have any real insight on if they will or not, but with GM's history with the Solstice so far (the GXP, the Z0K SSB racers, the Drift rcing Solstice, the Hot Rod LS7 Solstice) I think GM has proven they plan on keeping up with the Joneses with the Solstice at least. I also envision GM putting the LNF into a lot of other cars. Cobalt SS, HHR SS, G4 GXP, ION RL, etc. (GM waiting for the LNF would help explain the lack of a current HHR SS or an announced G4 GXP.)
 

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brentil said:
I unfortunately do not have any real insight on if they will or not, but with GM's history with the Solstice so far (the GXP, the Z0K SSB racers, the Drift rcing Solstice, the Hot Rod LS7 Solstice) I think GM has proven they plan on keeping up with the Joneses with the Solstice at least. I also envision GM putting the LNF into a lot of other cars. Cobalt SS, HHR SS, G4 GXP, ION RL, etc. (GM waiting for the LNF would help explain the lack of a current HHR SS or an announced G4 GXP.)
Yep, no doubt, I can't imagine they won't transplant this baby into many other cars. It's only a matter of time before you see the Cobalt and the Ion changing from thier superchargers to the turbocharged models.
 

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Yeah I have an ION RL and the instant access power from the supercharger is great, that's why I prefer them over turbos, but when a car looks as good as the Sky, I can make exceptions!
 

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I took the factory Supercharger off my 2001 Ford Lightning (check out my home page for a few pics...), and stuck a couple of snails on it, and wouldn't have had it any other way after I did. I have a 87 Buick GN, and have owned an 89 Turbo Trans Am as well.

Lag does exist simply because of physics (time it takes the exhaust volume to fill and spin up the turbine), but there are ways to almost eliminate it, or make it seem like it's not there.

That being said, from the look of the HP graph I saw, I think everyone should be well pleased with the responsiveness of the Redline and GXP. :cheers: :thumbs: :thumbs:
 

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Discussion Starter · #13 ·
Buzz Lightyear said:
I took the factory Supercharger off my 2001 Ford Lightning (check out my home page for a few pics...), and stuck a couple of snails on it, and wouldn't have had it any other way after I did.
Are the "couple of snails" twin turbos ? If so, the good results you achieved are not surprising, since twin turbos are a proven way to reduce lag. My concern is with a single-"snail" :lol: setup, as in the Sky and GXP. However, based on the feedback to my original post, it sounds like I don't need to worry. Thanks everyone for your input ! :thumbs:
 

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SKY USA said:
Are the "couple of snails" twin turbos ?...
Yes they were, but I had pretty bad lag to start with because the turbos were too big for the stall converter in my tranny.

I don't think there will be any noticeable lag on these cars. :D

BTW, look for my truck in Ford Truck Performance magazine the end of this month/1st part of June. :cool:
 

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Discussion Starter · #15 ·
Buzz Lightyear said:
Yes they were, but I had pretty bad lag to start with because the turbos were too big for the stall converter in my tranny.

I don't think there will be any noticeable lag on these cars. :D

BTW, look for my truck in Ford Truck Performance magazine the end of this month/1st part of June. :cool:
I checked out your webpage, and you've done some nice work! :thumbs:
 

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You mentioned mid 70s turbo cars. Don't forget we can tune fuel injection (and direct injection) a million times better then an old carb'd turbo setup. With timing curves able to advance before boost with modern ignition systems, fuel tuned much more accurately, and much better turbo design (not to mention variable valve timing etc) turbo lag on an OEM car is much much more tame.

There's no need to spray nitrous to spool a STOCK turbo. Get a boost gauge and check for vaccum leaks first ;)
 
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