Power mods for a basically stock car.
09-16-2010, 05:51 PM
#32
Rennlist Member
Join Date: Jun 2010
Location: Dallas, TX
Posts: 2,529
Likes: 0
Received 0 Likes
on
0 Posts
09-16-2010, 05:52 PM
#33
Rennlist Member
Join Date: Jun 2010
Location: Dallas, TX
Posts: 2,529
Likes: 0
Received 0 Likes
on
0 Posts
09-16-2010, 08:38 PM
#34
Rennlist Member
Join Date: Jun 2010
Location: Dallas, TX
Posts: 2,529
Likes: 0
Received 0 Likes
on
0 Posts
after reading the response now I am really curious if I have a stock turbo? 
I'll take it for a drive and see if indeed it does drop at redline. I had to be careful setting the adj. boost to keep it at 17!!
Dumb question...is there a relatively easy way to verify???
If it's not stock then that sure explains why it pulls THAT hard?
I'll take it for a drive and see if indeed it does drop at redline. I had to be careful setting the adj. boost to keep it at 17!!
Dumb question...is there a relatively easy way to verify???
If it's not stock then that sure explains why it pulls THAT hard?
^^^ I've got a similar setup so I'll chime in on that. My car hits 17 psi in 4th/5th gear pulls up to ~5400rpm on the original k26/6. I'm positive it's a 26/6. So ya, the k26/6's will hit over 16 psi. I think the reason why Porsche ever so diligently switched to the 26/8 was because if you look at a dyno chart comparing the 2, the 26/6 drops off like a cliff because it can't HOLD the boost as long as the 26/8. So it won't hold the torque and thus won't let HP climb much more. That's exactly what happens with my car past 5400rpm; time to shift up or she runs outta *****.
By the way, I'm running a LR DP wastegate, not currently running a MAF.
By the way, I'm running a LR DP wastegate, not currently running a MAF.
09-16-2010, 09:14 PM
#35
Burning Brakes
Thread Starter
It might be possible that with certain wastegates the stock turbo can hold more than 12 psi boost to redline.
But, the bottom line is that the stock compressor can only flow for a little over 300 crank hp (maybe even less if the ambient pressure it sees is less than ideal). So, it doesn't matter how much boost you're seeing at redline, that's all the power you're gonna get.
I know a lot of guys get real horny when they see their high boost reading at redline, but chances are their making very little more actual power than the guy witnessing the boost bleed-off thing. That high boost reading looks good on the boost gauge but it's all turned into heat and crazy back pressure.
The orginal poster said he'd like between 300 and 350 rwhp; so you have to upgrade the turbo.
But, the bottom line is that the stock compressor can only flow for a little over 300 crank hp (maybe even less if the ambient pressure it sees is less than ideal). So, it doesn't matter how much boost you're seeing at redline, that's all the power you're gonna get.
I know a lot of guys get real horny when they see their high boost reading at redline, but chances are their making very little more actual power than the guy witnessing the boost bleed-off thing. That high boost reading looks good on the boost gauge but it's all turned into heat and crazy back pressure.
The orginal poster said he'd like between 300 and 350 rwhp; so you have to upgrade the turbo.
racerxrick - clarks garage shows how to tell if it's a stock unit. take a look down near the oil dipstick to see the trubo, and if it has a flattened edge, it's a k26/6 housing.
09-17-2010, 12:53 AM
#36
Rennlist Member
onspeed;
with what you have on the car now, you're probably at the 260 to 270 crank hp mark.
With a 26/8 and do the exhaust and a 3mm wastegate shim, and maybe a mild cam , you'll be at a bit over 300 if everything is working right. At that point everything, except for the MAF, will be maxed out. After that, you'll need a bigger turbo and a chip remap for bigger injectors.
with what you have on the car now, you're probably at the 260 to 270 crank hp mark.
With a 26/8 and do the exhaust and a 3mm wastegate shim, and maybe a mild cam , you'll be at a bit over 300 if everything is working right. At that point everything, except for the MAF, will be maxed out. After that, you'll need a bigger turbo and a chip remap for bigger injectors.
09-17-2010, 03:40 AM
#37
Burning Brakes
Thread Starter
So basically it's all about upping boost? What's the average limit of the engines? I thought 15-16psi was the safe zone, but seems like there's a good number running 17?
edit - so what i've got in mind is a 3'' catless exhaust, new wastegate, MBC @ 16psi?, and i think i'll get that DIY tuning that rouge_ant did and retune. Along with a boost gauge and wbo2. Hopefully i'll be good for 250-260whp? Right now, I'm dead even with stock m6 LS1 f-bodys, if I'm on boost. I'd like to be able to crawl or walk one. When I have the time and resources, maybe a turbo upgrade to something larger that can hold a higher boost. I hear k27/6 is the best of all worlds? Boost tapers off very little, quicker spool up, good fitment, relatively cheap?
question on running catless. I hear the exhaust is much dirtier? Like will it blacken my rear bumper?
edit - so what i've got in mind is a 3'' catless exhaust, new wastegate, MBC @ 16psi?, and i think i'll get that DIY tuning that rouge_ant did and retune. Along with a boost gauge and wbo2. Hopefully i'll be good for 250-260whp? Right now, I'm dead even with stock m6 LS1 f-bodys, if I'm on boost. I'd like to be able to crawl or walk one. When I have the time and resources, maybe a turbo upgrade to something larger that can hold a higher boost. I hear k27/6 is the best of all worlds? Boost tapers off very little, quicker spool up, good fitment, relatively cheap?
question on running catless. I hear the exhaust is much dirtier? Like will it blacken my rear bumper?
Last edited by onspeed; 09-17-2010 at 04:22 AM.
09-17-2010, 11:00 AM
#38
Burning Brakes
Join Date: Apr 2009
Location: Westchester NY
Posts: 1,167
Likes: 0
Received 0 Likes
on
0 Posts
So basically it's all about upping boost? What's the average limit of the engines? I thought 15-16psi was the safe zone, but seems like there's a good number running 17?
edit - so what i've got in mind is a 3'' catless exhaust, new wastegate, MBC @ 16psi?, and i think i'll get that DIY tuning that rouge_ant did and retune. Along with a boost gauge and wbo2. Hopefully i'll be good for 250-260whp? Right now, I'm dead even with stock m6 LS1 f-bodys, if I'm on boost. I'd like to be able to crawl or walk one. When I have the time and resources, maybe a turbo upgrade to something larger that can hold a higher boost. I hear k27/6 is the best of all worlds? Boost tapers off very little, quicker spool up, good fitment, relatively cheap?
question on running catless. I hear the exhaust is much dirtier? Like will it blacken my rear bumper?
edit - so what i've got in mind is a 3'' catless exhaust, new wastegate, MBC @ 16psi?, and i think i'll get that DIY tuning that rouge_ant did and retune. Along with a boost gauge and wbo2. Hopefully i'll be good for 250-260whp? Right now, I'm dead even with stock m6 LS1 f-bodys, if I'm on boost. I'd like to be able to crawl or walk one. When I have the time and resources, maybe a turbo upgrade to something larger that can hold a higher boost. I hear k27/6 is the best of all worlds? Boost tapers off very little, quicker spool up, good fitment, relatively cheap?
question on running catless. I hear the exhaust is much dirtier? Like will it blacken my rear bumper?
That's a good start.
09-17-2010, 05:55 PM
#40
Dude, I would hope that you would make more than 260bhp w/ a k26/8. I have a 88 turbo s with authority stage 2 chips and make 260bhp(257bhp IIRC). I also wonder about a 27/6. I know that it would spool differently and not give as much boost as my current, but don't know when the boost would happen and how much I would loose from the change. I am happy with my turbo and wont replace it till it dies or modifications dictate it.
09-17-2010, 10:28 PM
#41
Rennlist Member
I think he's got a k26/6.
That's the weekest link in the system, and that will dictate the max power potential.
It's not about just upping the boost. You can add all kinds of boost controllers and wastegates, and that could increase your midrange punch, but also hide inefficiencies in the upper third of the powerband.
I'm not a fan of the k27/6. It makes good amount of boost quickly, but creates too much back pressure on the engine (especially if it's allowed to hold high boost into the upper third of the powerband) which takes away from the power potential and increases the threat of detonation.
I like Porsche's use of the k26/8, and with the right supporting mods it will be the most economically efficient way to have a wide powerband with fairly early boost onset and rev out to 300 reliable crank hp, But if you're going to do a turbocharger swap anyway, I guess you might as well go to a bigger turbo.
Unless, you're running pig rich, I haven't heard of a blackened rear bumper from no cat.
That's the weekest link in the system, and that will dictate the max power potential.
It's not about just upping the boost. You can add all kinds of boost controllers and wastegates, and that could increase your midrange punch, but also hide inefficiencies in the upper third of the powerband.
I'm not a fan of the k27/6. It makes good amount of boost quickly, but creates too much back pressure on the engine (especially if it's allowed to hold high boost into the upper third of the powerband) which takes away from the power potential and increases the threat of detonation.
I like Porsche's use of the k26/8, and with the right supporting mods it will be the most economically efficient way to have a wide powerband with fairly early boost onset and rev out to 300 reliable crank hp, But if you're going to do a turbocharger swap anyway, I guess you might as well go to a bigger turbo.
Unless, you're running pig rich, I haven't heard of a blackened rear bumper from no cat.
09-18-2010, 04:22 PM
#44
Three Wheelin'
