[Z OH 6]

Simple question that probably only a few people can answer that have done this. For those that have swapped the stock OEM 1.7L blower for a Magnusson 2650R...

1. At the same boost level, is it even noticeable?

2. With the improved cooling from the 2650R does it help at all for casual driving?

3. Is there any perceived loss of power due to the larger blower rotors at part throttle when not under boost?

I'm asking because I'm still not certain I want to take my car beyond 700whp where it is now, but curious if there's really any noticeable benefit to the 2650R at this power level just due to the improved intercooler cooling. It seems like an expensive upgrade without going any further.

I suspect I know the answer to this but just curious to hear from anyone that has done this and really looking for honest answers here, not just a salesman pitch that the 2650R is better because I'm already fully aware of that.

[JasonGofast]

Magnuson 2650 is pointless for 700 whp. The LT4 will be faster and torquier. It'll run cooler for sure. I can do back to back runs and see no loss of speed. Not something I'm sure you'll notice if you're just cruising. I'd only get the 2650 if you're planning for 800whp+, but it does make for a nice show piece when you pop the hood.

[laynlo15]

Well I haven't swapped from one to the other since I didn't have a zl1 but since I worked for Magnuson during the 2650 development and I ran the 2300 and 2650 on my Camaro ss I can tell you that you'll have much better cooling no matter what the rpm your running at. You'll notice the power difference and tuned properly you'll have all the bottom end power your car can handle. You won't be disappointed. You can't make consistent power with high IATs and even my 2300 had those and at 140 IATs it was pulling timing down track. My IATs dropped over 30 degrees on my logs on the big end going thru the traps. Less cool down times, more power at lower boost levels from the 2300 to the 2650. I disagree with Jason Go Fast and I have no dogs in this hunt since I don't work for Magnuson anymore. Just giving you the skinny how I've seen it and others also.

[JasonGofast]

What part do you disagree with? Stock blower cars will run better times if you're just gonna leave the car at 700whp. They also will be torquier too. The only benefit I can see the 2650 having at 700 wheel is cooling. Only other benefit I can think of is the power felt easier to control as the peak was at redline.

[Camaro1973]

Originally Posted by Z OH 6

Simple question that probably only a few people can answer that have done this. For those that have swapped the stock OEM 1.7L blower for a Magnusson 2650R...

1. At the same boost level, is it even noticeable?

2. With the improved cooling from the 2650R does it help at all for casual driving?

3. Is there any perceived loss of power due to the larger blower rotors at part throttle when not under boost?

I'm asking because I'm still not certain I want to take my car beyond 700whp where it is now, but curious if there's really any noticeable benefit to the 2650R at this power level just due to the improved intercooler cooling. It seems like an expensive upgrade without going any further.

I suspect I know the answer to this but just curious to hear from anyone that has done this and really looking for honest answers here, not just a salesman pitch that the 2650R is better because I'm already fully aware of that.

I swapped my stock car with the 2650r , and headers for my first mod. It was a nice 110rwhp gain over stock. But as you said your already at 700 or close to so there's no point unless you start pumping meth or add cam, headwork etc.


You'll lose a bit of low end torque as mentioned as well, your cooling with be a ton greater. But boost for boost on stock blower its not much different. Only when u start pumping boost around 15psi they really start to shine.

[Camaro1973]

Originally Posted by JasonGofast

What part do you disagree with? Stock blower cars will run better times if you're just gonna leave the car at 700whp. They also will be torquier too. The only benefit I can see the 2650 having at 700 wheel is cooling. Only other benefit I can think of is the power felt easier to control as the peak was at redline.

Better times on 1st cold pull. Even at 700wheel with stock blower without a whole lot of cooling mods that blower will heat soak very fast, so i don't agree with this at all.


Go compare that stock blower on a 90F day compared to the 2650 on a 90F day. Its going to lose power.

[laynlo15]

I've never seen any data that shows a 700 hp lt4 is faster then a 700 hp 2650. Besides if your making 700 with an Lt4 you'll make more hp with the same boost with a 2650 on less boost. My 2300 made 770 on about 16 psi and swapped to the 2650 a made over 840 on 13 psi. Anytime you can make the same hp on lower boost in my opinion thats a good thing. You are right it does look bitchin when you open the hood. I always hear people say I'm happy with 700 rwhp and then hp goes to your brain and you can't stop wanting more hp. It is a very easy swap also but to each his own and there are a lot of ported lt4s making great power but you really have to push them to get there. Magnuson just made it easier. I really depends on the needs of the buyer, drag racing, tracking or just street. They'll both blow the tires off at about any mph you want.

[Z OH 6]

Good discussion peeps and it seems you guys are basically debating the same questions I have. No question the 2650R is the way to go above 800whp but as laynlo15 stated, I do wonder if due to the increased cooling, is there less chance the ECM would pull timing? I don't know what IAT temp the ECM starts to pull timing. I know on a Hellcat but not on this platform. Also, typically larger blowers with larger rotors eat up more power when not under boost so that made me wonder does the 2650R actually reduce power slightly when not under boost as JasonGofast may be eluding to, smaller blower spins up quicker due to less rotational mass?

[radz28]

I don't have stock logs, but I have logs with the 2650, obviously. And - in the interest of full transparency - my comments come from my car (and another similarly equipped), which is not a DD. And to try to add context to how much I drive (and how much could be butt-dyno "improvements"), I bought this car in 09/19, added the blower in 05/20 (with about 900-miles on the car at that point), and the car is currently at 2300-miles. I'm adding those comments just to give relativity to any "how it feels" comments I'll add below. And I'm no tuner or expert - I do fiddle and have had some tuning successes, though. And I hope something out of this mess will be helpful. I'm not going to argue with anyone else, because I only know what I've experienced, and add what I've read and seen. And I have no dynos' to prove anything, so I don't want to suggest that, either.

Originally Posted by Z OH 6

Simple question that probably only a few people can answer that have done this. For those that have swapped the stock OEM 1.7L blower for a Magnusson 2650R...

1. At the same boost level, is it even noticeable?



Not to sound argumentative, but even with an adjusted bypass, I was only seeing about 11-psi MAX boost, stock (going by the IP gauge). With a CARB-intent-setup, boost is going to be around 14-psi (probably another pound or two with boost weather coming and low DAs), so I don't know if I'd say the boost level is the same. The other car like mine will see almost 16-psi (in 90* Summer weather - we saw almost 19-psi last winter with the same combination, but different tune )with a ported 95, port-matched snout, and RFBG. Yeah - the 1740 winds-up quicker and dies-off up top, but unless you race all the time, I'm not sure most could tell a difference down low. A car set-up similar to mine will start burning-up MT SSs, from a 30-roll (in 3rd gear) by about 4000-RPMs (on the street - in 80+ degree weather), and oftentimes spin through the 3-4 shift easily. The tires aren't in the best strip condition (in the interest of full transparency), but I'm not sure it would be fair to say a 2650 in terms you're asking would be a dog. It might be a little easier on the engine, since torque will be a little less in lower RPMs. Anyways - the 1740 will hit harder, if you have the traction to make use of it, but the 2650 carries-out better - probably even in this set-up. The 2650-cars I dealt with directly RIP.

2. With the improved cooling from the 2650R does it help at all for casual driving?

It won't help until you get into the throttle. Without airflow demand, the intercoolers aren't doing much to strip the heat. On a 90+ degree day, in traffic, MATs will get in to the 170s easily, but as soon as there is airflow demand, they drop temps quick. The longer the run - the more MATs drop. My IAT 2s are consistently less than a 20* delta from IAT 1s (I do have the breakout harness with the IAT 2-sensor right in the #2-cylinder port). MATs are always higher because of the way they extrapolate the values. If you're running enough E', you could probably do the same and just mess with the IAT adder on the 1740. With about a 93-94-octane blend of Racegas Concentrate, on a 90* day, I've seen no knock retard after zero'ing out the IAT adder table until about 160*. We stopped there because we didn't have a need to go further, but I was commanding about 22* of advance from around 1.4-1.6 airmass (and I see 1.6). So - if you mean just fartin' around, maybe having a little fun on the street - I'd say you'd probably see a little improvement - but not much. Would I recommend being as aggressive with timing as I am? Probably not. We're not done tuning that car though. There needs to be vehicle speed and airflow demand, though, for there to be a benefit.

3. Is there any perceived loss of power due to the larger blower rotors at part throttle when not under boost?

I'm asking because I'm still not certain I want to take my car beyond 700whp where it is now, but curious if there's really any noticeable benefit to the 2650R at this power level just due to the improved intercooler cooling. It seems like an expensive upgrade without going any further.

I suspect I know the answer to this but just curious to hear from anyone that has done this and really looking for honest answers here, not just a salesman pitch that the 2650R is better because I'm already fully aware of that.

I don't feel any loss. As soon as I roll-into the throttle, I get pushed back into the seat. The more I push down, the more I get shoved back. I don't miss any torque, and never feel like the car isn't responsive. If I TWITCH my foot, the car MOVES OUT. The larger rotors will take more power (I think GM said like 120-horse or something for the 2650-rotor pack), but the rotors have a more aggressive twist and are more efficient, so I doubt most people will be able to tell a difference from the seat. I wouldn't pretend to tell you or anyone else you couldn't tell a difference though.

If you didn't up the boost on your combination (I can't recall if I noticed you stating you had or not...), I don't know if a 2650 would gain you much, since you'd probably not be creating much more heat. If you're still on stock pulleys, and have optimize airflow/exhaust, I really don't think the delta in heat between the two would be much. It seems to me the easiest way (in the context of this thread) to make 700, is going to be the easiest on the engine, and a smaller blower is better if it can make the number. If you're running E' now, I doubt you'd be able to swapping over to a 2650, and therefore I don't think you'd get much benefit (the cooling effect of the E'). Again - all speculation based off of what I've read and watched though. I think the E' is a bigger benefit than a 2650 at 700'. I don't know that a 2650 would benefit your combination much. Also - it isn't like GM thought a stock LT4 bottom end didn't need a little improvement for LT5/2650. Better bearings and crankshaft show adding the additional drag and power required some improvements to the LT4, so there could be something said for that, too. Those bigger rotors beat on the reciprocating assembly more. Although - those bigger rotors are spinning slower. Does that mean a 1740 will wear-out faster since it's spinning quicker? Does that matter?

Will a 2650-car be faster than a ported-1740-car (when equipped the same otherwise)? I'm positive the 1740-car will jump-out from a dig faster, but I'm not sure it will hold that lead 1320' later. I wouldn't know though. Is it better for your combination? Probably not, if I understand it right. Yeah - I'm running one. But - that's for specific reasons and circumstances you likely don't have to worry about. Would I do it again this way? YUP.

[Camaro1973]

Originally Posted by Z OH 6

Good discussion peeps and it seems you guys are basically debating the same questions I have. No question the 2650R is the way to go above 800whp but as laynlo15 stated, I do wonder if due to the increased cooling, is there less chance the ECM would pull timing? I don't know what IAT temp the ECM starts to pull timing. I know on a Hellcat but not on this platform. Also, typically larger blowers with larger rotors eat up more power when not under boost so that made me wonder does the 2650R actually reduce power slightly when not under boost as JasonGofast may be eluding to, smaller blower spins up quicker due to less rotational mass?

132F timing can be pulled via MAT. But remember there’s adders too so it’s not an exact science. But anything usually over 130F it’s very common to start pulling a degree or 2. Could even be as high as 4 degrees on stock tune at the top.

Stock blower makes more torque simply because it’s smaller and spins faster, but it’s complete shit at top end.

[radz28]

Originally Posted by Camaro1973

132F timing can be pulled via MAT. But remember there’s adders too so it’s not an exact science. But anything usually over 130F it’s very common to start pulling a degree or 2. Could even be as high as 4 degrees on stock tune at the top.

Stock blower makes more torque simply because it’s smaller and spins faster, but it’s complete shit at top end.

Unless it's ported. It seems like Kong and Joker have some good port jobs.

[laynlo15]

I really never had to worry about intake temps like I did with my 2300 and it always went over 140 IATs when the temps were above 80 degree. Most of the times the staging lane lines were long and you had to restart the car all the time. I saw 150 to 160 at the Camaro Fest many a time with the 2300. I never came close to seeing even 125 when I reached the burn out box and down track when it counted I was generally 110 IATs and making plenty of power and never having to worry about pulling timing. I didn't have an ice box in the trunk or any kind of chiller to help cooling cause I just didn't need it.

[Z OH 6]

Thanks everyone for your input. I think I have all the answers I need. We can keep the discussion going if you wish but I think in the end the result is still that it's going to be a very negligible gain at best without more boost and fuel on a 2650R. I have the standard Kong port on the OEM blower and the car is pullied making 700whp at 14-15psi of boost through 2" headers and Green high flow cats. I dont honestly think I need more power because I'm at the limit of the street tires traction now and I don't want to run a drag radial all the time to enjoy the car. I was considering the 2650R for the more consistent MATs but that's very pricey to upgrade to the 2650R for that small gain. I think the 2650R doesn't make sense until I'm ready to do a cam, if I ever make that decision.

[ZX-10R]

Originally Posted by Z OH 6

I have the standard Kong port on the OEM blower and the car is pullied making 700whp at 14-15psi of boost through 2" headers and Green high flow cats.

But can it keep making that power over successive pulls without heat soaking in high ambient temps, that's the question - and I highly doubt it. Ok for joyrides down a country road I guess

The big selling point on the 2650 is consistency of intake temps over successive pulls, especially in summer

To me a 2650 is mod #1, even before headers or anything else