askulte

Jonathan at BristolDyno was great, and really helped us get many runs in just 3 hours. The directory with all the Dynojet runs (and a free viewer from dynojets website) is at:
http://www.bristoldyno.com/vehicles/.../Skulte_Andris

1st run was right as-is off the street - mostly under 4 psi - 455 hp & 445 tq

Not logged, but we did some steady state with the dyno brake (the only Dynojet 248 w/ a brake). I was overpowering it at low rpm, no boost, and it would only hold it for about a minute before the brake would overheat & start slipping. I think there's some good video of my cast iron manifolds glowing cherry red! (Got to get the EGT's in there) I'd like to play more with the steady state & ignition timing next time, but it's not just not beefy enough for more than a minute or two at a time it seems.

2nd was a bit warmer, no changes - 459hp/454 tq
3rd run I added 2 degrees of timing - 33 at 0, 31@ 2 psi and 29 @ 5 psi - picked up another 20 hp (480/473), right around 5600 rpms
4-7 I was trying to richen things up (losing battle, trying to get it down to 12.0,from 12.5) no real increase (478-487hp and 467-481 tq)
8 I tried my ghetto boost controller, which spiked to 17 psi @ 3500 rpms! Jon let off immediately... That was 407hp @ 579 tq at 3500, and a 12.7 air/fuel
9 something happened (it's in my notes), and jon let off. Maybe an intake pipe blew off...
10 I was full open on the ghetto boost controller (now known as the GBC), and had 1.2 psi more boost (4.66 vs 3.5) up to 5500. 485/506
11 More of the same boost, playing with fuel
12 Closed up the GBC one more turn, for a whopping 6 psi boost! 520/539
13 Closed GBC one more turn - 8 psi baby! 535/577 - Even though the air fuel wasn't too horrible (12.7 & steady), Mike Rizzi (a longtime friend that drove up from NY) noticed my fuel pressure started dropping from 4000 @ 60-ish to 30 psi! Eeek! Air/fuel still showed good, so compensating with more pulsewidth works for now.
14 Closed GBC to 1/2 turn - 11.5 psi, but let off at 4000, Very choppy run w/ 40 hp peaks & dips, I believe it's the dropping fuel pressure not giving good atomization at that boost level). 470/622 Thought it might be spark, but it's has the Accel 300+ CDI, and the plugs are gapped at .035.
15 Opened GBC a little, 7.5 psi to 4500 & dropping to 6@5500 540/578
16 Tweaked the GBC, 8.5psi to 4200, drops to 4.3@6000, and added the K&N filters & hose (the others were just open turbo) - 510/610. More power to 4600, but then drops off compared to #15, but I think that's the 1/2 psi boost difference. I need something more repeatable!
17 Closed off the GBC, for zero wastegate action. Blew apart the line from the IC to the TB @ 18 psi. 462/638@3800

Jonathan mentioned his boost measurement was reading a bit low. I'm thinking about 2 psi low compared to the screen in CALMAP, but I didn't log anything. I learned that 2 degrees of timing is worth 20 hp. I'd like to try more later to see where it plateaus, once I get a second Walbro in there. The fuel pump just can't keep up at more than 7 or 8 psi boost (how much are the stock 3/8" hard lines good for?). I also need to bolt together my intake piping with tabs & aluminum bars so they don't keep blowing apart at 12psi+. I need to wash the K&N's, and maybe fab an air box, get air from the hood, and run aluminum mandrel bent pipe instead of 3" flex hose. I also need bigger injectors than the 55lb/hr Siemens in there now.

The GBC - It's a needle valve with a .040 bleeder port before it, then tees for the wastegates after the needle valve. The valve has 4 turns, but only really seems to modulate from 3/8 turn to 5/8 turn from closed, so possibly something a bit more sensitive would work, or a larger sized bleeder.

A big thanks to Jonathan for staying late, Mike Cheney, Mike Rizzi, and John Santos for helping out, and keeping a watchful eye (various popped off pipes, wideband sensors flying, etc!), and my dad for videotaping in HD (I'll get that converted and online soon).

In short, I picked up 65hp & 34tq, at the same boost, by the replacing the SLP catback with the boom tubes & adding 2 degrees of timing. The TQ curve is almost identical to 4700 rpm, then the old SLP catback TQ starts dropping quite a bit (40 ft-lbs low @5500 rpm). It's at 480/480 rear wheel & 5 psi on the street as I rolled out. I think I'm going to see if I can get some 10, 14, and 18 psi wastegate springs to have on hand (and not use the GBC) for next time. Turn it up, baby!


Link for full res picture - http://www.skulte.com/z28tt/BristolDyno.gif

sleepybu

whats your combo ...please

junkcltr

iTrader: (1)

Nice setup you have there. Thank you for taking the time to write and post this info. I know it takes some time to do a good post like that.

Once you have the boost controller stable it should be more consistent. IATs were probably messing with things a bit too. Cherry red manifolds....I like that. I have done that to my modified TPI manifolds a few times. How much timing were you running in the end with what static compression? street gas?

askulte

Thanks guys. The 5 second version of my combo is:
399 cid Dart Little M, JE 8.1:1 pistons, Swaintech coated, tight squish, AFR 210 heads, banks tt manifolds, 236/230on113 cam, single plane Accel Pro Ram intake with 1200 cfm tb, two TO4E turbos.

Full details at http://www.skulte.com/z28tt/archives...ine_specs.html

I've been asked what opens the dyno run files (.drf files) posted above - Dynojet has a free viewer on their website.

Junkcltr - Thanks. 8.1 compression on 93 octane pump gas. During the dyno tuning, I raised the timing to 33 at 0 boost, 32 at 3.6 psi, 29@7.3, 27 at 10.9, and 25 at 14.5. Once the new fuel system is in, I'll be more comfortable, and won't pull out as much timing per psi. It picked up about 20 hp & ft-lbs by bumping the 3.6 and 7.3 psi timing cells by 2 degrees, FWIW.

I spent 4 hours cutting down 20 minutes of footage to 4 minutes last night.

http://video.google.com/videoplay?do...46413965&hl=en

This is just the first run and some steady state tuning off the street - you can really hear when the dyno loads the engine near the end... I'll get the other runs done tonight.

I stripped the sound out of the dyno video for a 750 kb mp3 clip:
http://www.skulte.com/video/bristoldyno_sound.mp3
Be sure to put this in your ipod, and crank up the stereo on the daily driver!

vwdave

I can tell you right now those clamps you have on your intake hoses are not ideal for turbos. If you havent already, you need to get every boost hose bead rolled on the ends and get some t-bolt clamps. We have several 300-550whp vw's running t-bolts with upwards of 35psi of boost with no failures. (When properly installed of course)

askulte

I know... The intake tube gets blown off at 18 psi... All the tubing has beaded ends, and I'll be welding tabs & pinning them together, which will take the tension load. I've got V-bands on some of the joints, just couldn't find the rest in the garage before dyno time. It's still winter here, he he he.

21 psi * (3in)^2 * pi / 4 = 150 lbs forcing the pipes apart, not counting the spike when the throttle is closed to shift. For comparison, a 2" pipe with 35 psi is 110 lbs. BTW - Are you on TurboMustangs? Say hi to Rob at Force-EFI, if you're the same guy. We had a nice chat this afternoon, and hopefully he'll get that Firebird w/ the D1 finished & sold.

Andris

RaverRacerX

whats ur overlap on the ivo with that cam?

vwdave

Yeah thats me. My shop is a block from his so I see him from time to time. Super nice guy and very intellegent. I got to go over there and give him some money for the XFI I ordered tommorow. Expensive assed hobby.

(His D1 powered car is a Camaro RS. )

askulte

IVO? Intake Valve Open? The cam is from from CompCams, using the 3316 extreme energy hydraulic roller lobe for the intake and 3315 for the exhaust, with 1.6 rockers. At .050 lift, it's a 236/230 on a 113 lobe separation angle, installed 4 deg advanced (as ground). Comp has specs on those lobes in the back of the catalog with duration at .002 lift as well, I believe. Feel free to do the math to figure out overlap duration.

Andris

Sonix

iTrader: (1)

oh my god Andris, looking at that link you posted - I'm EXTREMELY impressed. You've documented just about everything I can imagine. You gave new meaning to the term "blueprinted".
That kind of dedication is flat out amazing.

One question, .020-.022" top ring end gap on a 4.121" bore motor? That seems tight for such a high powered machine. Did you gap to those specs yourself on purpose? (reasoning?)

What is the max PSI of boost you have planned to run on the street? 6psi seems low with 8.1:1 CR.

EvilCartman

iTrader: (1)

Video is unavalible

askulte

Thanks. I got tired of keeping track of all the 6x9 notepads, so this way it's all in one place!

The ring end gaps were based on JE's reccomendations, between street turbo and race blown: http://www.jepistons.com/dept/tech/d...instrc2618.pdf
Street Turbo: 1st ring .005" per inch of bore
Race Only Blown: .006" per inch of bore
The first land is pretty thick, so the ring is really down there, protected from the heat, in addition to the thermal barrier coating on the piston.

I built it with the intention of running 15 psi on the street/road course with 93 octane pump gas. Right now, the Walbro 255 lph pump or 55 lb/hr injectors won't let me. If I ever get the drag racing bug again (broke too many drivetrain parts trying that!), I can put in some 116 racefuel, and really turn up the boost & timing!

Alternative location on streetfire.net: http://videos.streetfire.net/search/...eb00174961.htm

vwdave

Have you considered building a surge tank for the fuel pump?

BDR

somethin is up if you're only putting down those numbers with a 399ci engine. Torque looked good though.. I figured they would be close to the same.. combo is nice.. good block , bottom end, heads etc.

askulte

Re: surge tank, I'd like to keep things as simple as possible. I don't think there's any advantage to doing that & an external pump, vs going to a single external pump and a sump.

480 rwhp at 4 psi is about 375rwhp without boost (run number 7, 480 hp & tq). It's low compression, & has a pretty restrictive exhaust & cam compared to a racing NA motor. 20 psi will wake it right up...

A.

Sonix

iTrader: (1)

I'm a noob, can you explain what this is or how it works?


Right on. Sounds like you really know what you're doing, that just sounded on the small side to me. But with coatings and 1/16" rings and a thick ring land, I imagine you'll be ok. You probably have virtually no leakdown with that

BDR

its a good buildup w/good parts.. lookin forward to readin the update w/20#.

vwdave

What it is, is a small aluminum can that varys between a cup, to a gallon. You put it inline to your auxiliary pump and during normal operation, the tank is full. When youre racing, the engine can get all the fuel it needs for a short period of time. Its sort of a bandaid fix where his proposed idea of a sump and external is the ideal way to go.

xpndbl3

iTrader: (5)

most of the guys are running the bigger walbro pumps when they get to this level, i believe it's a 325 or something ? The GN guys use them all the time on their boosted motors.

84z28350

Some people have used those large inline fuel filters for surge tanks too!

Steven89Iroc

I just saw this thread, nice write-up (as usual). Real data always outshines guessing and bench-racing, thanks. I can't wait to see what it'll do with more fuel and boost!

I've been pretty quiet on the matter, but this car was my original inspiration for all things thirdgen turbo, well before I knew anything about turbos, and the reason I really wanted to turbo one (the blue is a just a coincedence, I promise!). The documentation and build-up have both been excellent long before turbos were popular on these cars, not to mention the overall theme has stayed consistent for years! (That's hard to find with modified cars). Oh, and twisties are way more fun than straight lines anyway (though unfortunately, a lot more expensive).
Great job on the car Andris.

If anyone hasn't seen his "logbook", it's an interesting read.
http://www.skulte.com/logbook.html

Kingtal0n

Good work, makes me want to boost something with more than 3L of displacement these days.