Spool Comparisons

[Butters Stoch]

Hot topic with these new
CES/STEED twin scroll manifolds.

This could be useful for those building, have built, thinking about building, seeing where u are at, comparing where you should be etc etc.

Those with data logging ability can post logs for those to see.
It would be best to post a short list of build sheet. Hardware can change where your at in the power band immensely.

*Turbo including back housing AR
*fuel type
*rear gear ratio
*cams
*Displacement
*gear tested


Also, for those that would like to request data from a member , just ask. We are here to help.



Here is mine
Dropped the hammer at 2400rpm 4th gear, 20 psi target.

.

My results...

2.9L M52 @ 8.8:1 CR
S52 Cams - Ported head stock valve size
94 Pump fuel
AR Fab V1 Twinscoll T4
GT4094R w/ 0.9x housing
12 psi spring in both gates - no boost control only bottom of the gates are connected to turbo, both gates dumped to atm.
3" Turbo back to Vibrant Ultra Quiet + Vibrant Black 3" to dual out
Stock ZF w/ 2.93 LSD
255/35/18 rear tires

WOT @ 2100-5000 in 4th gear on the street

0 psi @ 2100
2.46 psi @ 2500
4 psi @ 2800
5.22 psi @ 3000
6.67 psi @ 3200
8.7 psi @ 3400
11.16 psi @ 3600
12.6 pis @ 3800
holds 12.6-12.8 till about 4500 RPM where boost creeps to about 13.3-13.7 psi

you can DL the .csv of this 4th gear pull here: http://schnell-engineering.com/SK/4th-gear-spool.csv

I tried to look through a bunch of datalogs from last year trying to find something approximately like the conditions asked for and can't haven't found much. I usually start most pulls in 2nd or 3rd and alot of them I am pedaling do to spinning on the street. After reviewing alot of logs this is what I have come up with

1 psi 3200 rpms
5 psi 4000 rpms
10 psi is about 4500 rpms
20 psi is about 5100 rpms
32 psi is about 5300 rpms

Once it hits about 15 lbs the boost line pretty much goes vertical so I am sure it would make boost sooner in 4th or 5th gear. Setup was a 2.8L non vanos M50 with a home made twin scroll equal length manifold and a cast wheel S366 with .91 T4 housing and 4" exhaust. Obviously its going to be down quite a bit from not having vanos and being little as well.

[E36 HateR]

Recorded a video when my car was running to get an idea of where it was, no datalogging yet but

*downpipe/exhaust - 3.5inch dp to 4inch exhaust.
*turbo manifold - custom t3 tubular top mount.
*Turbo including back housing AR - 6764 hx40 t3 .70ar
*fuel type - e85
*rear gear ratio - 2.93
*cams - s50
*Displacement - 2.8
*gear tested - 2nd gear

4100rpm showed 23psi, im sure with the headlamp ram air I could get that down 2-300 rpm.

[pbonsalb]

Can we do a standardized test in addition to whatever other tests people want to do? Like 4th gear steady 2000 rpm cruise, floor it and either log or lift at 3000 and 3500 and note boost at that rpm.

[Butters Stoch]

Can we do a standardized test in addition to whatever other tests people want to do? Like 4th gear steady 2000 rpm cruise, floor it and either log or lift at 3000 and 3500 and note boost at that rpm.

That's what I was hoping for.

[spenka]

Recorded a video when my car was running to get an idea of where it was, no datalogging yet but

*downpipe/exhaust - 3.5inch dp to 4inch exhaust.
*turbo manifold - custom t3 tubular top mount.
*Turbo including back housing AR - 6764 hx40 t3 .70ar
*fuel type - e85
*rear gear ratio - 2.93
*cams - s50
*Displacement - 2.8
*gear tested - 2nd gear

4100rpm showed 23psi, im sure with the headlamp ram air I could get that down 2-300 rpm.

Is this 6764 hx40 from TurboLab? I'm thinking its the same turbo I have with a t4 .81 A/R.


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[E36 HateR]

Can we do a standardized test in addition to whatever other tests people want to do? Like 4th gear steady 2000 rpm cruise, floor it and either log or lift at 3000 and 3500 and note boost at that rpm.

This would be a nice addition.

Is this 6764 hx40 from TurboLab? I'm thinking its the same turbo I have with a t4 .81 A/R.


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Yes same one

[spenka]

This would be a nice addition.


Yes same one

How do you like it so far? What do you think of it? I have not put my setup together yet and trying seriously hard to get it done by summers end. I still have a whole bunch of things to do.


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[boostd4]

Back in my 20's I had a 2nd gen MR2 Turbo and we had a spool comparison thread with requirements. We always did 4th gear, steady at 2000rpm, then WOT. For that model we used the term "spool" to describe when the vehicle made 200wtq (on a dynojet) under these conditions.... i.e. "My car on a GT2860RS spools at 2800rpm" and everyone would know what that meant. Was very convenient. Especially since backhousings, exhaust piping, all sorts of things can change when a car makes a certain amount of boost. Torque is torque.. just harder to get data without a dyno

[Butters Stoch]

Back in my 20's I had a 2nd gen MR2 Turbo and we had a spool comparison thread with requirements. We always did 4th gear, steady at 2000rpm, then WOT. For that model we used the term "spool" to describe when the vehicle made 200wtq (on a dynojet) under these conditions.... i.e. "My car on a GT2860RS spools at 2800rpm" and everyone would know what that meant. Was very convenient. Especially since backhousings, exhaust piping, all sorts of things can change when a car makes a certain amount of boost. Torque is torque.. just harder to get data without a dyno

That's the hope where we go. I'm going to log a 4th gear drop the hammer at 2k to 4500.

[pbonsalb]

Another standard test might be when do you hit 15 psi in 2nd, 3rd, 4th and 5th from a 2000 rpm cruise on level ground. I'd be happy to do a test but the tests don't mean as much unless we all do the same test. Loggers will be the most accurate of course. The WG spring (or gate pressure if electronic controller) should also be noted because the person opening at 10 psi so he won't exceed 15 psi will spool a little slower than the guy not opening the WG until 15 psi because he is targeting 20 psi peak boost.

[boostd4]

I think we could eliminate 2nd and 5th... 2nd will be wheelspin for a (possibly) majority of folk, and 5th will be jail time (on the streets). 3/4 would still be meaningful.

[vollosso]

Butters, ill post some logs i have from a few cars. I suggest you compile them back in the first thread though like the tq thread..


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[chikinhed]

I think we could eliminate 2nd and 5th... 2nd will be wheelspin for a (possibly) majority of folk, and 5th will be jail time (on the streets). 3/4 would still be meaningful.

3rd is wheel spin as well. 4th will be most consistent.

[Butters Stoch]

3rd is wheel spin as well. 4th will be most consistent.

I did a pull in 4th from 2k to 4k. WG set to open at 13psi and target was 16. I'll upload tomorrow.
Here is a 5th gear pull, same target 16 psi. Let her rip at 2400 till target boost.

[Matutino]

I did a pull in 4th from 2k to 4k. WG set to open at 13psi and target was 16. I'll upload tomorrow.
Here is a 5th gear pull, same target 16 psi. Let her rip at 2400 till target boost.

Dude, you wear glasses... you are disqualified.

[PEI330Ci]

Does everyone agree to this method?

4th gear
Start @ 2k RPM
Stop @ 4k RPM
15 PSI Boost Target

[Matutino]

I would say up to 4500 RPM

[pbonsalb]

4500 is for the slow spoolers or to show creep? I expect to be all in by 3500.

Also, do we want 15 psi or 20 psi? Probably the lower number will be one that more people run and those running more could dial back to it.

And again, we have to note the WG spring (or boost controller setting to send the signal to the WG) because the person running a 15 psi spring is probably opening at 10 psi. If I set my boost to 20 psi and open at 15, I should have faster response to 15 psi than the guy opening at 10 psi so he won't go past 15.

[NOTORIOUS VR]

I don't understand why people want to stop at a predefined boost level.

If you're looking for spool data, 2500-5000 should be a sufficient window for all types of turbo and gearing (load) setups.

[chikinhed]

I've used 20 psi for all my testing and logs so far. I also have my boost set higher so that I'm seeing how the turbo, manifold, engine etc interact to affect spool and not how the WG is modifying the curve.

Also, I've mentioned this before that people have to keep in mind that the boost pressure in the intake manifold does not always match the torque available. I may have 19-20 psi at 3000 rpm but the car doesn't start to pull until 3500-4000 rpm. Getting the turbo to spool sooner may not affect the torque curve as you'd think with out doing other engine mods to target the lower cirque curve you desire. Then you would be sacrificing top end power.

[Matutino]

2500 to 5000 would be ideal

[chikinhed]

I think 2500 is too late especially for the small turbo guys. You can see the affects of that on Dyno runs. I agree with staying on it thru a higher rpm though.

[Matutino]

That makes sense, then 2k to 5k 4th gear 20psi target

[PEI330Ci]

Also, I've mentioned this before that people have to keep in mind that the boost pressure in the intake manifold does not always match the torque available. I may have 19-20 psi at 3000 rpm but the car doesn't start to pull until 3500-4000 rpm. Getting the turbo to spool sooner may not affect the torque curve as you'd think with out doing other engine mods to target the lower cirque curve you desire. Then you would be sacrificing top end power.

We're comparing turbo/manifold response, not power.

I totally get what you're saying about power though; my ENGINE has 10 PSI at 3k RPM, but I don't feel like I'm making power until 4k RPM!

- - - Updated - - -

That makes sense, then 2k to 5k 4th gear 20psi target

Would everyone be able to do this with pump fuel?

Just a question....

[dburt86]

Dont put a boost target on the test. Just RPM range. 2k-4k in 4th and see where people start making boost. The difference between 10psi and 20psi is going to redundant because of how people have there controllers setup. Manual controllers will take longer to reach target, ect.

But regardless of the controller type, the initial spool wont be effected.