rear axle mounted turbo

[2QUIK6]

Originally posted by Whut
This was gone over a lot at ls2.com with mixed results from the members.

I think it sounds awesome and the performance gains are great.

The biggest complaint from others was how easy they thought water could get into the turbo with such a short exhaust pipe.

Has anyone ever had the problem, or is this just what the tire-kickers are thinking could happen?
I would think you could easy fabricate a plastic cover over the filter, kind of like placing a can over the filter so that only the open side faces to the back and have atleast 1" clearance around the filter so that airflow is not restricted.

If it works as advertised, then I could figure out a way to protect the filter from water.

 

[Whut]

Originally posted by 2QUIK6
Has anyone ever had the problem, or is this just what the tire-kickers are thinking could happen?
I would think you could easy fabricate a plastic cover over the filter, kind of like placing a can over the filter so that only the open side faces to the back and have atleast 1" clearance around the filter so that airflow is not restricted.

If it works as advertised, then I could figure out a way to protect the filter from water.

Register over at LS2.com and ask that question. Some members have that set up and I havent seen a post complaining about it so I would guess its a good system.

 

[Buick From Hell]

Originally posted by Ted A.
I would have to imagine there is a significant loss of heat energy before the turbo. I guess I can't slam them for the work they did, it just doesn't sit right with me mounted there.

"heat energy" does nothing to make a turbo work--moving air makes 'em work! "Heat energy" just happens to be how an engine MAKES it's moving air. Moving the turbo way to the back probably helps make MORE power BECAUSE there's less exhaust heat to raise the temp of the intake charge!

(and [my idea], if they could put heat-sink fins on the turbo-to-intake tubing, [and why not the exhaust piping for that matter?] the intake charge would be cooler yet!)

The ONLY downside I can see from this setup is the time it takes to get enough exhaust airlflow to the turbo AND the time it takes to pressurize all that intake tubing...LAG. However, and I'm just guessing, all that extra time probably adds up to a couple of tenths of seconds at worst...

 

[F8L Z71]

Sorry i missed this thread. I don't go in here too much except for the Alky forum.

I have pretty much all the pros and cons of the STS kit worked out and it runs pretty damn good on my truck. If you guys have any questions I'd love to offer a hand. In real world terms, not advertisments.

 

[gn4u2c]

Very cool setup there was a 1500 5.3 sierra at my work with the sts setup a few weeks back. very quiet and the owner claimed very quick I hope to se him up at cecil this summer.

As for the ls1 cars the bottle is excellent . a very close friend has a 01 WS6 275 drag radials, spec clutch, walbro pump,200 wet shot. 11.60@120 !! with a 2.02 60ft. OH and a k&N air filter.
silly fast with less that 1,800 invested. If you went to mustang/ f-body event a capital you saw him Blue WS6

 

[F8L Z71]

Cool!

Once you start going beyond the base kit though tye are not so quiet anymore. With the GT67, no cats and a big cam mine is actually too damned loud. I had to put amuffler on it. LOL

In the videos it's not real loud though

Vid against a blown and nitrous'd 4-Runner. My intake blows off sometime after the 1/8th and I redlight like a SOB. the truck wouldn't stay behind the line .

http://my.starstream.net/f8lpony/F8L 4x4 12.95@94 8psi launch.wmv

 

[n20junkie]

I have not test driven a car with one of these kits, but one thing we all know is that there is alot more to a engine than peak numbers, part throttle operation, from a stop acceleration and others make up how a car drives, and i would be willing to say that alot of guys that put these kits on their cars are not super knowlagable in the turbocharged engine area of automotive, so their impressions are that only of most people, sure its faster, i am not saying it isn't, but how is the driveability as compared to a twin turbo or a up front single, but many said it wouldn't work, me included, and it does work, i just wana see how well.
Grant

 

[2QUIK6]

Originally posted by n20junkie
but how is the driveability as compared to a twin turbo or a up front single, but many said it wouldn't work, me included, and it does work, i just wana see how well.
Grant

I would think the drivability would be similar to any turbo car. Remember these LS1's and LT1 have alot of pep without the turbo at all compared to our TRs with no turbo, so a little bit of lag is going to be no problem on these motors.
With that said, there should be no additional lag compared to an under the hood turbo with a front mount IC. The displacement of the pipe running from the rear to the intake is no more than that of an under the hood going to a FMIC and the displacement of the FMIC itself and back to the intake. As far as filling the pipe either way, as soon as air begins flowing in, it will cause a pressure rise at the other end almost instantaneously, it will be quicker than you could notice anyway.

The draw back is that LS1's have a 10:1 compression and LT1 have 10.5:1, thats a little too much compression to run more than 5-7# of boost max. You're going to see alot of folks bolt these on since its so easy and crank the boost up and blow up their motors cause they don't know the dynamics of turbo charging.

Those that have lowered their compression by changing pistons have then lowered their overall hp #s before turbocharging and maybe the lag will become more of an issue for those cars running a bigger turbo. I think the stock turbo that comes with these kits is about the same size as our TR stock turbos, T3 I think.

All in all, when I put a 383 stroker and forged 9:1 compression pistons in the '95 TA, I plan to get one of these kits because forced induction is the only way to make big hp numbers with these cars without filling an N2O bottle everytime you turn around. N/A about 500rwhp is the most you can make and be streetable.

 

[F8L Z71]

The stock kit uses a 60-1 turbo with like a .68 A/R I believe.

On my 5.3L I started of with a GT35 an not IC, just methanol. With my stock 9.5:1 CR and a 3000stall there was a second of lag then BAM! full boost and tire spin city. At 35mph I could punch it and the truck would just kick sideways and roast the tires till I lifted.

I blew up that motor durring an engine fire so I installed some 6.0L heads to drop compression to 8.6:1 and installed a GT67 .81 A/R and added the FMIC. Now I have a ton of lag. It's kinda like a Supra with a big turbo. I don't see full boost till about 4K or just over 4K RPM. I bought the big turbo to see what would happen and I was rewarded with excellent top end but laggy bottom end.

Drivability also worsend in that at part throttle merging onto a freeway I would sit at 5psi (low boost setting) and the truck felt like I was towing a 5th wheel. If i let it boost up higher then it was a whole different story since I'm tuned for 13-14psi, not 5psi.

Other than the drivability is great. I've rideen in a few LS1 cars with these turbos and the drivibility was MUCH better than my truck since they were tuned for 5-7psi.

I never dyno'd my truck after the GT67 install but on the GT35 with our newbie tuning and methanol (no IC) it still turned out decent #s for a truck motor and my insane drivetrain loss (remember my wheels weigh over 50lbs each and I have a tranfer case).

If you do the math on my best run a couple months ago. 5250lbs and 110mph it comes out to over 500rwhp. Still not too bad for a turbo that was never supposed to work. LOL

All that being said I still firmly believe a front mount is going to be better for overall performance due to area under the curve. So I'm not going to argue there.

 

[F8L Z71]

Ohh, I used to race an 87' Mustang GT with a built 351 and S-Trim Vortech, then my 00' T/A had heads/cam, nitrous and a 4400 stall so I am not toally new to moding cars and racing them. Heck I was the only one I knew back in the mid 90s who's daily driver had skinnys on 24/7. LOL

 

[n20junkie]

i think that if you built an engine for a turbo it would run kinda crappy with this system, due to the long length of pipe prior to the turbo, the high compression is what is makinginf high cylinder pressure in the lower rpm areas which is keeping the turbo spinning, and allowing quick spoolup, its similar to the stage II guys that run much higher than 8 to 1 ratios to allow quick spool, if you dropped the CR to 8 to 1 i think these rear mounted cars might turn into dogs.
grant

 

[2QUIK6]

Agreed, for the higher psi applications, a front mounted turbo would be best because you do need a bigger turbo to do it effeciently. For 5-7psi applications, the lag would be minimal and no IC is needed. If you read of the f-body forums, there's lots of agruments about it, and alot of folks do not understand turbo dynamics and how heat does help a turbo spoolup...alot of folks there don't think so but the hotter the gases, and higher the pressure and the easier the turbo will spool....thats why us TR guys like to lean it out at the bottom end as much as possible or you can set the timing so that flames are going out the headers..either way heats it up good and creates great spoolup.

Also for 10+ psi, you have to have an IC, or alky, which with an IC adds alot more piping and that much more pressure drop.

 

[Renthorin]

what happens if you go through a huge puddle and spray a wave of cold water on the turbo?

 

[F8L Z71]

Originally posted by Renthorin
what happens if you go through a huge puddle and spray a wave of cold water on the turbo?

A puddle like this?

Here are some vids they took in the Tacoma

http://i.b5z.net/i/u/1473169/f/Video/tacoma4.wmv

The other vids can be found here:

http://www.ststurbo.com/tacoma_at_the_lake

I my experience water is no biggy as long as you're not boosting high without the drycharger "sock". Water hitting the turbo doesn't hurt it at all. It will cool it down and maybe cause you to spool slower but if your in the rain WTF are you trying to boost for anyway? LOL

That being said I did ingest a TON of water once while driving in a monsoon style storm for 2.5hrs. I was running a much longer filter than comes on the stock kit and it sits right under the gap in the bed and cab of my truck so when dirivng slow all the water from my roof pours onto it. I also wasn't wearing my "sock" and I tried to hit high boost and that's when it happened. I lost some compression on 2 cylinders. I later went out on low boost with the sock on and floored it everywhere to test it out and didn't have even one little problem. So IMO, wear "protection" and you can play all you want. LOL

Ohh, I'm a 4x4 so I'm ok with boosting in the rain. Well I was, with all the new power I just spin all 4 tires.

 

[Renthorin]

I like the idea of the turbo behind the rear axle for ease of install. Saw them install that system on a camaro on "Two fags garage" last weekend.

My only thought about putting one on my truck was rocks hitting the turbo and plumbing and water hitting the hot turbo and cracking it.

If you say you have been playing in the waves and no problems that is good to know

 

[F8L Z71]

yeah, I drove mine around in all kinds of water and hitting puddles. Now rocks on the otherhand. I wouldn't think hiting a boulder is going to be good. LOL