Taking a Stock Engine with Stock Turbo to the limit....

[bison]

if the goal is to see how far the stock turbo can go, you can have the exhaust wheel clipped. And perhaps extrude-hone the exhaust housing.

Bob

There isn't much to clip on the stock turbine. It's like a paddle wheel as it is. Almost no exducer


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[TurboBob]

ahh, gotcha, I haven't looked at one in a long time... I do have that stocker I need to send your way, maybe I should put it on the car and see how hard I can spin it.....

 

[bison]

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[TurboBob]

turbine wheel graveyard.

 

[bison]

Expensive scrap


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[seedling]

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Wow! The boulevard of broken dreams!!


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[Mr.Spool]

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Love your graveyard

 

[Jerryl]

I think the way to squeeze a bit more is to run Q16, with an absolute minimum amount of methanol. This should lower the drive pressure.
Great job @murphster

 

[murphster]

So made a few more runs last night. Only thing changed from last time out was the valve springs were shimmed up to see if it would help the power drop off at the higher rpms. They were in the low 80s and ended up a little over 100lbs. I shifted anywhere from 4650 to 4800 and if anything, the accelerometer data showed the 4650 shift was better. I could probably use a little tighter converter that drops down to 4100 on the shifts, its consistently dropping down to 4250 right now. Track wasn't the best and spun the one time I left hard so couldn't get that killer 60ft. I turned up the boost each pass but it pretty much ran the same....11.53, 11.47, 11.53. I did set a best mph though at 116.18. I am car no. 7721:

 

[murphster]

The 60fts were pretty consistent. I tried hitting it harder on the second pass and spun so didn't try to hit it hard on the last pass so I could get a clean run in. I can't power out to a low 60ft like I used to on my fast engine, I will have to leave hard on the launch to get the 60ft lower. Looks like something around 3900-4000 rpm at 12-13psi will get me there. I left at 3600 and 8psi for the high 1.5 60fts.

 

[murphster]

So as far as boost, I tried adding boost in 1st and 2nd gear compared to a couple weeks ago to see if the 1/8th would pick up. I actually lost a little mph. I went to 22psi down low and ended at 21psi vs 20psi down low a couple weeks ago ending at the same 21psi. Logs show the backpressure went up dramatically going from 20 to 22psi in 1st and 2nd gear.

For the last pass I upped the boost more. I could only get 22psi in 1st gear but it went up to 24psi in 2nd and 25psi in 3rd. It didn't make a difference and went the same mph. Turbo seems to be done at 21psi. The timeslips even show a modest gain from 20psi to 21psi. Here is the 3rd run on the left vs the 1st run last night. A lot more boost but the mph and timeslip is nearly identical. These runs have similar timing but the higher boost run is definitely richer at the higher boost the way my AF tables are set up. Could have hurt power but historically I haven't lost power on alky running richer AF ratios.

 

[murphster]

So just to get an idea of how high the backpressure is getting, here is 24-25psi 11.53 pass from last night vs the 20-21psi 11.46 pass from a couple weeks ago... backpressure is the light blue noisy line

Backpressure went from 42.2psi at 20.8psi boost (2.03:1 ratio) to 63.7psi at 25.1psi boost (2.54 ratio). Yikes.

 

[murphster]

So, I think the plan is to continue to shift around 4700... still seems to lose power above that and the backpressure also goes up. I am going to try and keep the boost at 21psi for the whole run and maximize power there by adding timing and leaning it out a little more. Got to get the 60ft down too.

 

[1952ray]

So, I think the plan is to continue to shift around 4700... still seems to lose power above that and the backpressure also goes up. I am going to try and keep the boost at 21psi for the whole run and maximize power there by adding timing and leaning it out a little more. Got to get the 60ft down a little more too.

Damn, what a great job. If I had your knowledge my car would be so fast the paint would peel off before the traps!!! Man what a great thread

 

[~JM~]

Damn, what a great job. If I had your knowledge my car would be so fast the paint would peel off before the traps!!! Man what a great thread

Doesn't the paint peel off anyway?

No matter what speed....

Very educational post. Thank you for the effort & information.

 

[Mr.Spool]

So as far as boost, I tried adding boost in 1st and 2nd gear compared to a couple weeks ago to see if the 1/8th would pick up. I actually lost a little mph. I went to 22psi down low and ended at 21psi vs 20psi down low a couple weeks ago ending at the same 21psi. Logs show the backpressure went up dramatically going from 20 to 22psi in 1st and 2nd gear.

For the last pass I upped the boost more. I could only get 22psi in 1st gear but it went up to 24psi in 2nd and 25psi in 3rd. It didn't make a difference and went the same mph. Turbo seems to be done at 21psi. The timeslips even show a modest gain from 20psi to 21psi. Here is the 3rd run on the left vs the 1st run last night. A lot more boost but the mph and timeslip is nearly identical. These runs have similar timing but the higher boost run is definitely richer at the higher boost the way my AF tables are set up. Could have hurt power but historically I haven't lost power on alky running richer AF ratios.

View attachment 303963

It might on the stock turbo as well as a low timing.

 

[Mr.Spool]

The 60fts were pretty consistent. I tried hitting it harder on the second pass and spun so didn't try to hit it hard on the last pass so I could get a clean run in. I can't power out to a low 60ft like I used to on my fast engine, I will have to leave hard on the launch to get the 60ft lower. Looks like something around 3900-4000 rpm at 12-13psi will get me there. I left at 3600 and 8psi for the high 1.5 60fts.

This is interesting to me.when you ran the stock turbo years ago when the car was heavier was the leave rpm and boost similar for similar 60fts?

 

[murphster]

On my GN I left at 10lbs boost for a 1.58 60ft and on my other car 3200-3300 off a tbrake for 1.60 60fts. Thats all the data I have. The tbrake'd converter was probably tighter so didn't need as much rpm. Only needed 3600 tbrake launches to get a 1.53 with a .85 TE44. The GN had just a restalled D5 so that's prob all it had off the footbrake.

I should probably turn the 2 step back on to get the launch dialed in and try adding 100rpm at a time. Looks like a narrow window for the optimal launch in that 3600-3900 range. I'm just leaving when the tach hits my number but its coming up so fast its hard hit my number consistently. Once I get the fuel correction minimized on the launch I will turn off correction while on the tbrake and use the 2step. Right now it would go a little lean. I'm trying to tune it out by adding fuel through the MAP rate of change table and increasing the MAP AE kPa limit for this to kick in rather than through VE adjustment. I got some of it out through VE but the MAP rate of change should do the trick. Well, I hope. Interestingly, I had the same issue with my truck and Bison super fast spooling mfs6262. It would go lean on a fast increase of boost and the Classic Fast I have in the truck couldn't keep up compared to XFI. Increasing the MAP AE kPa limit pumped in some fuel and fixed it.

 

[TRICKSIXPA]

Scott what size tires are you running? What are the gears in the back? I'm sure you told this before.


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[SCOOBY DOO]

Great info and data...thank you.