Five months after installation of my D1SC, I finally have track results! Keep in mind the engine has not been modified in any way since removing my SN2000.

I'm going to leave out any runs in which I used nitrous for the sake of comparing blower to blower. My best time with the SN2000 is a 12.57 @ 106.72. My intent last Friday was NOT to beat this, but to shake down the car and make sure everything was operating properly (including me) and to log data on my Auto Xray to analyze.

I also wanted to see if I needed to lock up my torque converter>>> Because of the SN's low redline, this limited my engine rpm's to about 5,200. Because of this, I used to run out of top gear and found it necessary to manually lock up the torque converter just to get me to the finish line. The D1SC does not have this limitation, so I wanted to see if third gear would carry me to the finish line without having to lock up my converter.

I ignored reaction time also. Here are the results of my first "shake down" run:

R/T: 1.413 (on a 0.500 tree)
60': 1.84
330': 5.20
1/8: 7.98
mph: 88.54
1000': 10.36
1/4: 12.35
mph: 113.55

So without trying, I beat my previous best with the Paxton and my mph was WAY up. I did not have to lock up my converter either!!!

I do have one concern though. My knock sensor kicked in like I've never seen it. With my Paxton, I never saw knock retard in excess of 4 degrees (with full timing at 38 degrees). On my best run, I logged up to 10 degrees of retard (with 35 degrees). Maybe I should reinstall my water injection?? Or does anyone have any other ideas on why I'm seeing more knock?

On my first run, Not only did I not heat up my Hoosiers enough (could definitely feel traction loss), but I also went a little sideways when hitting second gear!!

My second run was the best, a 12.26 @ 113.17 with a 1.74 60-footer. This was with heating up the tires even more. I still felt traction loss though.

I should also mention that my SN was producing 6-psig boost. My D1SC produced between 5 and 6 psig, similar to the SN. Knowing this, I promptly removed the D1SC and shipped it back to ATI for a "pulley reduction" and a checkup (still under warranty). I sense 11's are easily around the corner, considering this blower is capable of gobs more boost that six pounds!!

------------------
Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
Former Paxton (6-psig): 12.57 @ 111 mph.
Former Paxton (6-psig) & former 50-hp nitrous: 12.04 @ 114 mph.
Current ATI D1SC (Initially 10-psig): Projecting high 11's.
Future ATI D1SC (15-psig): Gotta catch them pesky 26-psig boosted TTA's!!

http://willie.camaro-firebird.org/

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

[This message has been edited by Willie (edited May 07, 2001).]

 

Willie Congrats all the way around, get that site updated with some new pics when you can. I am interested in the mounting of the intercooler, hiont hint. I think the main difference your seeing now is the intercooler that the Paxton did not have. I know the ATI blower should be more efficient also. Route the ATI without the intercooler and see what she runs at 6PSI? But you would need a slower pulley to do that, the intercooler is eating about 2-3PSI to get it across it. So without the intercooler you would see about 8 PSI I think. I have been thinking of switching to ATI or just back to the Turbo, not sure yet?

 

Seeing that the trap speeds are up a good amount indicates more HP. Makes me think that you are getting more air into the motor (not surprising, right?). this being said,
maybe adding a little more fuel will help with the Knock.

Dont you have the Carrol superfueler? i printed up the manual, but have not had a chance to read it yet. cant you dial up on the additional fuel buy clicking up on the #9 & #10 controllers?

If i am not mistaken you went from a non-intercooled to an intercooled right? the reason to ask is that although you are @ the
"same" pressure, the mass of air is greater with the intercooled charge than the non @ the same pressure. check the IAT & see what the temp is, depending on where it is physically located, you might see that it is quite a bit cooler.



------------------
Bob Wooten
71 Camaro, 91 EFI
r71chevy@earthlink.net
www.r71camaro.homestead.com
<><

 

A couple of other points I should make.

1) With my Paxton, water injection was enabled at 3-psig boost. I ran a total of 38 degrees advance with this setup.

To date, I have not reinstalled this system so with the D1SC, no water was used. As a safety precaution, I did retard my total timing to 35 degrees.

I do not use a boost timing retard. Adjusting timing is done with an adjustable timing module.

2) No intercooler with the Paxton. The compressed air is routed directly from the blower to the throttle body.

I have a three-core IC with the D1SC. Yes, there is far more plumbing to get the air to the throttle body.

3) I have no way to compare inlet air temperatures because of MAT location. With the Paxton, it was located at the inlet (next to the air filter). With my D1SC, it is in the stock position (plenum). Therefore, the comparison is not valid.

True, BUT I believe that by having to lock up the torque converter well over two seconds before the end of the pass caused my engine to "bog" (kind of like shifting into OD) -- thereby reducing mph.

You would think so, but my MAF readings indicate the complete opposite. With my Paxton, the MAF would max out at 255 g/s and stay there for most of the run. With the D1SC, it was close to the magical 255 g/s, but only hit it on a couple of occasions through the pass.

I have been very concerned with running lean. That's why it took five months since installing the D1SC that I have been brave enough to run it hard. My Xray data indicates O2 readings in the low 900 range through the pass. Should I increase this with the Superfueler?

As I still have my Carroll water injection pump, it would be a simple thing to hook it up. When I get my blower back, it should be putting out substantially more boost. I'm tempted to install the water injection, just in case...

Willie

[This message has been edited by Willie (edited May 07, 2001).]

 

Willie,

IMHO you should run a Boost Timing control. You are now seeing 6psi of QUALITY boost. That means a lot more air. You definitely don't want to screw around with detonation. Get a Boost timing control on there and bump up the fuel a tad.

Tim

------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's with bigger cam, bigger stall, and bigger exhaust.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

Why don't you pull a plug and do a reading on it?

Are you getting black smoke at wot?

I have my fuel pressure set at 42#s no vacuum. However, when I watch my autometer fp gauge at WOT it rises above 50psi. I thought no vacuum at the plenum was supposed to simulate wot. But I have seen now 2 occasions where it does not. FP at WOT always was higher at WOT then no vacuum at plenum.

My 02 readings are in the low 900s as well. I also believe I'm a little rich. My knock retard is around 10 degrees too. Even when I had higher fuel pressure it did not decrease. I run full timing.

------------------
91 Formula 1LE 1 of 46
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 supercharger(SN93 upgrade), Ford SVO 24#injectors, Crane AFPR,SLP airfoil, ported/polished plenum, March alt. pulley,Crane Gold 1.6rrs,MSD coil,MSD6AL (5200rpm limit),Holley 9mm wires,Ac delco R43ts plugs,custom chip,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

Willie If you dont want that Carrol water pump I would be happy to use it Are you running the FMU or the Superfueler? Is the ATI FMU adjustable? What's your fall in RPM when you engage the lookup in high gear full throttle? I would drop some timing until you get that knock under control.

 

Willie, you dont need to retard any timing. Also, what kind of pulley did you have? if i remember right it was a 10lb pulley right?

you should be seeing 10lbs of boost at 5500rpm i dont think that your belt is tight enough. i commented on that over at CZ28.com. with my 3 core ic and 12lb pulley i saw 10lbs of boost at 5000rpm but i never went pas that.

Also, i think that maybe you should take a plug reading after one of those runs. If they seem dry maybe you need a colder plug.

Mine always ran best with 2 stage coler autolites. Those would be #24. #26 are stock.
also dont let your gap go above .035 even with MSD. i did and just blew out the spark.

i think that you need to play with the superfueler some more. If you are in the low .900mv that is good and means you are running rich, but anything more than 4* of knock usually means detonation but not necessarily.

I've gone through tons of problems with my blower and i'd be glad to help you out since i'm gone through most of them and have fixed most of them.

 

willie i think i might have found your problem. i just read that in your other thread that the superfueler uses a 2-bar map sensor. you dont need a 2-bar until you go over 15psi.

so if you are using the 2-bar for both boost and super-fueler that could be a major problem.

just thinking out loud

 

Hey Jim. He has better heads and cam so 12psi on your car and 6psi on his car may be the same amount of flow simply because he is running more efficiently.

Just my $.02

I think comparing a Paxton Sn2000 to a D1 is no comparison at all.

------------------
-86 IROC
a few mods
this years goal: 10.50 @ 130+ mph
-=ICON Motorsports=-

 

Let me try to address every question/comment. It will take multiple posts so I don't miss anyone. Here goes!!

It's not my site, but Jim Campbell's (aka DownUnderIROC). He was nice enough to set it up for me without asking. I'll e-mail him some pics soon.

I've got some pics if you're interested. Please e-mail me.

I definitely agree. All that ducting and the intercooler will reduce pressure. But it isn't practical to fabricate ducting that will direct airflow straight into the throttle body.

Willie

 

I've never believed that retarding timing is the way to go. That's why I have used water injection in the past. It has been very effective in eliminating detonation at 38 degrees. Why retard timing if you don't have to? It only causes lost power.

I just don't understand why my MAF airflow values that I recorded are not as high as with the Paxton. So I don't feel the engine is getting more air. Of course the MAF in the Paxton setup is placed before the blower and after on the ATI's. Could this cause different airflow values?

Willie

 

quote:

Makes me think that you are getting more air into the motor (not
surprising, right?).


You would think so, but my MAF readings indicate the complete opposite. With my
Paxton, the MAF would max out at 255 g/s and stay there for most of the run. With the
D1SC, it was close to the magical 255 g/s, but only hit it on a couple of occasions
through the pass.

quote:
I dont get this part? I would think a D1 would just blow away the 255 MAF like your old SN2000 and my paxton does? Anyone got any idea's? I'm wondering if your belt is slipping to now.

 

Maybe I should pull a plug. I am not getting black smoke that I'm aware of.

This is a normal occurrence. The fuel pressure regulator increases fuel pressure at approximately one psig per pound of boost. Mine is set at 53 psig (atmosphere) and rises to about 60 psig at 5 - 6 psig boost.

Agreed. 850 is a good number, but I've always run rich. It's insurance as far as I'm concerned.

My knock retard is excessive, but only at launch. I will speculate on this later.

Willie

 

I bet you would. I'm keeping it.... for now.

Superfueler. I ordered my ATI without the FMU, so I don't know if it's adjustable.

It's substantial... about 1,500 rpm's.

More on this later.

Willie

 

Willie
I just checked some of the other post's and saw your combo. Damn I like that cold induction you built! I did not read your opening post close, just skimmed it, I thought you had the P1SC not the D1SC, now that's a huffer! If I dont go back to the turbo, I will probably go with that one myself, and drop the NOS. I would like some pics of that intercooler mounted if you dont mind? I did not find the ATI literature that helpfull on this subject and when I called them it was like talking to Paxton, no usefull info

------------------
Paxton NOVI supercharger W9Lb underdrive Combo pulley, 75HP N20 shot for charge air cooling, SVO 30Lb injectors, Accel AFPR & 300+ ignition, coil and wires, airfoil(getting T/B bored to 2.080" Sold BBK 52mm), ported MAF(waiting on 512gm.sec fix)Bosch Platinum plugs & O2 sensor
E-Tec200 heads ASM LTR & portmatched plennum, Crane Gold 1.6RR's & ZZ4 cam(small cam=streetable). Steel crank & rods, TRW blower pistons W/ZGS rings, all balanced, splayed main 94Vortec block, 1 5/8" long headers, SLP 3"catback minus the kitty!
Moser 9", 35 Spline Detroit Locker & Moser axle's 3:50 ratio HRW 3.250 case with Daytona pinion support, Strange Billet housing ends & 1350 Billet yoke wearing 94Formula disc's held in by all Lakewood adjustable components. HI-TQ GER 700trans,
2400stall with Cyberdyne fuel PSI and trans temp guages on pillar guage pod, 24,000GVW B&M cooler. Edelbrock strut tower brace. Working on converting to 89 chip & wiring.

 

I'd like to leave my timing right where it is. I lowered total timing from 38 to 35 just in case, but the knock values did not decrease.

It is a 4.00 inch blower pulley, which is supposed to be a 10-lb pulley on a stock 350. Not only is my engine not a 350, but it's been modified. Apparently when ATI "calculated" the proper pulley, they were off quite a bit. (Nothing new here from my experience with my 305 and torque converters.)

Again, a good idea. In fact, I just picked up a set of colder plugs for next time!!

I run Corvette aluminum heads. The plugs I use are two steps colder than the standard plugs for an '89 Corvette. The plugs I just picked up are one step colder still.

My gap is at 0.035 and will remain there, even with my Jacobs Pro Street.

I honestly feel the knock retard I'm getting is false. BUT I don't want to take any chances.

I appreciate it. I don't perceive my performance as a "problem". I'm concerned over the knock values and really nothing more. The D1SC has been shipped back and I will be talking with ATI in the next couple of days to see what pulley I need to up the boost to drop about one more second (if possible).

Willie

 

I agree with everything you say. Boost values are relative and really can't be used to compare engine to engine. That's why it doesn't concern me that I'm only getting 5 - 6 pounds on a "10 pound pulley". This only means my engine breathes better than ATI expected.

Willie

 

And now a word of knock retard. But first a question. I will post this question on the Racing/Autocross board too. When I was doing my burnout, the raised area of my new cowl induction hood was bouncing all over the place due to the vibration caused by the burnout. Then when I launched, I definitely experienced wheel hop -- the top of my hood reacted in the same manner. Can a knock sensor pick up the car physically being vibrated?

I think the answer is yes because my knock retard of 11 degrees was at ONE mph!! The engine was revving 3,855 rpm's at that time. The succeeding recording (one second later) was at 6 mph. Knock was at 10 degrees. Then it drops to 6, 4, 2, then one (at 68 mph). From then on, the knock retard sustained at two degrees. Therefore, I believe the excessive knock retard on the front end was caused by the physical vibration of my car due to wheel hop.

Any opinions or ideas here?

Willie

 

I have seen knock sensors become over sensitive with age, not saying this is your problem though. I would also like to hear some of the super mod's idea's?

 

i did not know that you had different heads. so yes, your boost reading will be lower.

Second did you see what i said about the BAR reading on the MAP sensor?

Also i think that it is mostly false knock due to the high o2 values and also sometimes old knock sensors are notorious for bad readings. A local tuner around me (ASSC) doesn't even use them with DFI because they act too wacky...

 

Yes, but ATI was given all the information about my engine to calculate proper pulley size. But as I mentioned previously, I can understand how they took their best guestimate. I have had three aftermarket torque converters in three years and all three manufacturers (reputed "experts") were grossly in error in mapping stall speed. This includes Art Carr, Pro Torque and yes, even Precision Industries. It seems no one builds 305's in order to have some baseline figures.

Yes, I just had a "senior moment". My car is a MAF system. The 2-bar MAP is used exclusively for the Superfueler, nothing else.

My knock sensor is two years old (which really doesn't mean anything). As far as my O2 readings go, I've always run rich. With the Paxton, it was even richer; between 950 and 980 mV.

I still believe almost all the knock recorded was false, most of which occured at launch when the car was shaking. I have a knock disable switch I can use, but don't feel comfortable using it....yet.

In any case, I appreciate your thoughts.

Willie

 

Willie,

Couple of things. If i am not mistaken the MAF's are pressure sensitive, so it does not surprise me too much that it is reading different up stream than down stream from the blower. possibly you could post this question on the turbobuick web site & get fast question answered there (or check thier archives). I think that Grumpy is OOC for a few days so unfortunalty we cant pick his GN brain.

Second, you are right about the knock sensor. some of them will pick up strange things. for example sometimes they will pick up the noise from roller rockers & from roller lifters (non-hyd). this is why sometimes they get "dumbed" down when you install these kind of parts. I if you are getting knock during your burn out, there you might have a bushing deflecting & a bolt smaking the frame causing a "knock" that the sensor is picking up. considering that the knock sensor is nothing but a micro phone all it does is amplify noises.

BUT, also consider that @ max load, high throttle, min RPM is when you can see a LOT of knock. My bet is that the knock is there. a few tests, drop the timeing back a few degrees, if it goes away you have nailed it. OR, install your water injection, if that removes it you have found your problem.

my2c (along with all the others), keep spankin' it.

BW

------------------
Bob Wooten
71 Camaro, 91 EFI
r71chevy@earthlink.net
www.r71camaro.homestead.com
<><

 

Awesome Willie!!

Here are some of my thoughts on your knock retard.I seriously doubt it to be detonation related first off.It could be the anything especially at launch everything is flexing.The initial hit of the converter could also trigger it.The gears of that Whiney D1 being transfered through the engine when the initial load is put on them at launch.My thought are it bolts up to the head,and the coolent is a very good trnsferer of sound,hence where the knock sensor sits.11s are easy for you.I already have the 3.70 inch pully I ordered it right after I heard of you making only 6 lbs.Im expecting 10 or so,for now

I have found something that might be of intrest to you Willie in regards to MAF sensor.Seems Granatelli Motorsports,Company that makes the new GM sensors for lts and ls1 make some kind of adjuster for our year TPIs that allows you to use the bigger aftermarket Ford sensors,and or tunes your stock one for reading of more flow.Something to look into,I was kinda dumbfounded when I saw that.Keep us posted. Im gonna take a guess at your et and MPH if I might with a bigger pully maybe 10 lbs,the 3.70 inch.I'll say you will hit 118-120mph and a mid to low 11 with the car tuned correctly.I hope my estimates are conservitive though That 305 really moves.Good Luck

 

D@mnnn, there's that rumor about the Granatelli Motorsports f**d MAF conversion again! Anybody got some hard evidence about this thing's existence yet?

 

it out already I seen the ad for it

 

Where was the ad? How much?

 

I looked on the granatelli website and didnt see anything about it.

 

So where is this MAF converter? Me wants PROOF!

 

Sorry for the late reply... just catching up on some threads. IIRC the 2-bar MAP sensor is for boost under one atmosphere. A 1-bar MAP is for NA applications. 3-bar MAP sensors are used when you exceed one atmosphere of boost...

--andrew