The 14b Drag Race Discussion Thread

[gofer]

Cam gear changes dropped my 16g times from 10.6 or 10.7 to 10.3, but I was running fixed back pressure at the time so no way to know how that was affected.

Holy crap. Thanks for spending $200 for me this weekend Kevin, time to get some cam gears. Time to rent some dyno time and play with cam timing.

Even two-tenths is more than I could ask for...

 

[LandSpeed-DSM]

Cam gear changes dropped my 16g times from 10.6 or 10.7 to 10.3, but I was running fixed back pressure at the time so no way to know how that was affected.

I seem to recall you mentioning that you had your wastegates referencing drive pressure similar to Ferraris turbo F1 cars in the 80s. Was that something that you had developed on the compounds and just carried over to the 16g? Do you have a picture you would consider sharing?

Corey- The exhaust lobe, phasing and valve event timing play a large role in determining how much of the pressure and heat left over from the power stroke are sent down stream by changing when it opens and for how long.

Lower drove pressure at high rpm let's you cam more like an NA. Tighter LSA, more overlap.. opening sooner for longer. With less chsrge contamination

Edit: found one of the better articles again
www.carcraft.com/techarticles/ctrp_1106_turbo_camshaft_guide/viewall.html

 

[Kevin Jewer]

Nothing glamorous. Just boost pressure and MBC to the top port, side port left open. The spring itself will allow the WG to blow open at a fixed EMP. Then I used the MBC to make the spring "adjustable" to try various drive pressure levels. I did something similar back in 2002 or so using a standard air compressor regulator to beef up the spring for other reasons.

 

[pneumo]

Ha, it's funny you mention tuning it like an NA. That's another piece of the puzzle I looked into. Since boost pressure was falling as rpm went up I started looking at how top level NA cars are set up. Learned a thing or two.

 

[1qkfwd]

Ha, it's funny you mention tuning it like an NA. That's another piece of the puzzle I looked into. Since boost pressure was falling as rpm went up I started looking at how top level NA cars are set up. Learned a thing or two.

This is pretty much what I've been goin by. Been trying anything in the book an n/a car would benefit from and trying it out. Well except afr's. I'm more boost conscience about that.

 

[pneumo]

This is pretty much what I've been goin by. Been trying anything in the book an n/a car would benefit from and trying it out. Well except afr's. I'm more boost conscience about that.

How much 'boost tune' do you give it vs how much 'NA tune' when the boost is falling down to 15psi at high rpm?
From what I've seen, a typical pump gas boosted tune typically runs a richer AFR to keep the charge cool; the extra fuel mass helps soak up the heat which slows down the burn and reduces knock. If you're using C16 the knock suppression is excellent, so there's less need to run it rich for knock suppression, and if you have a really good intercooler there's less need for rich afr's to keep the intake charge cool. How lean have you gone so far? No peeking at my dyno chart until you answer!

 

[Phil1320]

 

[1qkfwd]

How much 'boost tune' do you give it vs how much 'NA tune' when the boost is falling down to 15psi at high rpm?
From what I've seen, a typical pump gas boosted tune typically runs a richer AFR to keep the charge cool; the extra fuel mass helps soak up the heat which slows down the burn and reduces knock. If you're using C16 the knock suppression is excellent, so there's less need to run it rich for knock suppression, and if you have a really good intercooler there's less need for rich afr's to keep the intake charge cool. How lean have you gone so far? No peeking at my dyno chart until you answer!

Well I know how lean you ran, you told me. But I'm still running a rock solid 11.7-11.8 afr for the power im making.

 

[pneumo]

Well I know how lean you ran, you told me. But I'm still running a rock solid 11.7-11.8 afr for the power im making.

Oh that's right, I did mention that at the track last spring. I have a confession about the AF ratio. I tuned my car without a wideband so I never knew exactly how lean it was. I just kept leaning it out and it picked up mph. At the end of the nitght after I ran 11.51 @ 118 mph I made a dyno appointment to do a baseline run at the next opening in the dyno schedule. That's when I found out how much power it made and saw the actual AF ratio. I was a little surprised to see the results!

So I'm not 100% sure I was getting the most power out of my setup.

 

[rhamlinii]

Oh that's right, I did mention that at the track last spring. I have a confession about the AF ratio. I tuned my car without a wideband so I never knew exactly how lean it was. I just kept leaning it out and it picked up mph. At the end of the nitght after I ran 11.51 @ 118 mph I made a dyno appointment to do a baseline run at the next opening in the dyno schedule. That's when I found out how much power it made and saw the actual AF ratio. I was a little surprised to see the results!

So I'm not 100% sure I was getting the most power out of my setup.

So how lean we're you?

 

[pneumo]

So how lean we're you?

At peak HP at 5700 rpm it was 13.1. From 5k to 6k rpm it's around 12.9-13.0. From 6k rpm to 7k rpm the AF ratio gradually dips down to 12.1.

 

[SBstar]

I can see where tuning like that could be beneficial on race gas, but what kind of effect do you think it would have on e85 which doesn't seem to gain power by going leaner the same way? Did you ever play with afr's on the 16g with e85 Dave? You guys are going to convince me to hop on a dyno just to have an idea where I'm at in this HP game for comparison.

 

[pneumo]

I can see where tuning like that could be beneficial on race gas, but what kind of effect do you think it would have on e85 which doesn't seem to gain power by going leaner the same way? Did you ever play with afr's on the 16g with e85 Dave? You guys are going to convince me to hop on a dyno just to have an idea where I'm at in this HP game for comparison.

I may not be the best person to answer that question, and you sorta answered your own question when you say that E85 is less sensitive to AFR. From what I've seen the benefits of E85 are greater when running a larger turbo at higher boost. Alcohol fuels are good at reducing knock since they cool the aircharge in the combustion chamber. The hotter the charge temps the better they perform. I haven't played around with E85 on a small turbo, but I'd imagine it would not benefit as much from the extra charge cooling at low boost. I could be wrong, though.

 

[1qkfwd]

I was starting to think that I was pretty tapped out on my tune up here. BUt all this discussion sheds new light on some things.

I think I really need to be able to know what my exhaust backpressure is. I think I need to start monitoring egts. I've been really trying to keep im Iats down as low as possible. Its working. My highest IAT was I think around 114 degrees with the coolant temps being 213 degrees. Thats the best so far. But I can only get the IATs so low.

I think that playing with backpressures and cam timing I can get my egts down a little more and get a bit more aggressive on the tune itself. I can really start tweaking it like an N/A tune. Doing it that way I think would make a well put together 2G head a huge benificial piece to making more power on the engine alone which in turn would help out getting more out of the 14B.

Now all this is thinking out loud. So ill leave it open for opinions.

 

[SBstar]

I may not be the best person to answer that question, and you sorta answered your own question when you say that E85 is less sensitive to AFR. From what I've seen the benefits of E85 are greater when running a larger turbo at higher boost. Alcohol fuels are good at reducing knock since they cool the aircharge in the combustion chamber. The hotter the charge temps the better they perform. I haven't played around with E85 on a small turbo, but I'd imagine it would not benefit as much from the extra charge cooling at low boost. I could be wrong, though.

I completely agree, and figured I'd answered my own question but figured it couldn't hurt to ask. The benefits of e85 at this level are purely based on availability and the fact I don't have to change tunes. I'd venture to assume I could make more power on race gas then on the e85 actually.

 

[Kevin Jewer]

Back to back runs on my car and the 16g on E98 were ~10.37 race gas and 10.31 E98. Neither fuel was optmized for timing though, so that's not a very good comparison, don't read into it too far. I did make another 3 mph on my own E80 mix the following year, but only made a couple of passes with crappy traction so I didn't get any improvement in ET (10.39 IIRC). Still seemed promising at the time. I do really like the ethanol on the bigger turbos.

 

[1SloEvo]

I may not be the best person to answer that question, and you sorta answered your own question when you say that E85 is less sensitive to AFR. From what I've seen the benefits of E85 are greater when running a larger turbo at higher boost. Alcohol fuels are good at reducing knock since they cool the aircharge in the combustion chamber. The hotter the charge temps the better they perform. I haven't played around with E85 on a small turbo, but I'd imagine it would not benefit as much from the extra charge cooling at low boost. I could be wrong, though.

If this is the case, then wouldn't you think E85 on a maxed out 14b would work very well? On those of you running 22+psi, that thing has got to be making some serious hot air. This is why I would think the ethanol would work just as good. I don't think the number will be as big, but the percentage gain I feel would be just as good. Just an opinion as I'm not into tuning yet.

 

[Steve93Talon]

If this is the case, then wouldn't you think E85 on a maxed out 14b would work very well? On those of you running 22+psi, that thing has got to be making some serious hot air. This is why I would think the ethanol would work just as good. I don't think the number will be as big, but the percentage gain I feel would be just as good. Just an opinion as I'm not into tuning yet.

My post-IC charge temps are within a few degrees over ambient whether I'm at gate pressure or maxed out on the 14b. I'd be very curious to see what E85 would be like with a hotpipe on the 14b. No pressure drop, should still be knock-free, and more alcohol friendly charge temps. Also a good chunk of weight reduction.

 

[1SloEvo]

My post-IC charge temps are within a few degrees over ambient whether I'm at gate pressure or maxed out on the 14b. I'd be very curious to see what E85 would be like with a hotpipe on the 14b. No pressure drop, should still be knock-free, and more alcohol friendly charge temps. Also a good chunk of weight reduction.

 

[Kevin Jewer]

Comp efficiency is a factor in air temps, but boost is a much bigger one. Even at 100% efficiency, 45 psi is far hotter than 20 psi. Seems obvious, but many people overlook this. Comp efficiency dropping from ~65% (nearly maxed out) to ~60% (maxed out) doesn't change much. Consider also that any heat added by compressor inefficiency is further reduced by IC efficiency, and it doesn't add up to much of a temp increase. Other downsides of maxing out a given compressor far far outweigh the "hot air" portion of it IMO.

 

[pneumo]

Comp efficiency is a factor in air temps, but boost is a much bigger one. Even at 100% efficiency, 45 psi is far hotter than 20 psi. Seems obvious, but many people overlook this. Comp efficiency dropping from ~65% (nearly maxed out) to ~60% (maxed out) doesn't change much. Consider also that any heat added by compressor inefficiency is further reduced by IC efficiency, and it doesn't add up to much of a temp increase. Other downsides of maxing out a given compressor far far outweigh the "hot air" portion of it IMO.

Agree. There's a helpful calculator at Stealth316.com to show the change in charge temps at different levels of boost, turbo efficiency, and IC efficiency.
Stealth 316 - Turbo Outlet Temperature
One thing I would NOT do is run a water-air intercooler with an ice box and any type of alcohol fuel.

 

[Bud92gsx]

Has anyone dynod on a 14b and e85 with minimal mods.

Id like to see those numbers please.

 

[gofer]

What are minimal mods Bud?

I'd say what pneumo had for a mod list was pretty minimal for his dyno numbers at 324whp/306tq running 25psi. The built bottom end and transmission upgrades aren't completely necessary, just insurance for those power numbers. Now, running DR's or slicks at the track, you'd want the drivetrain mods but as far as dyno numbers go it's a minimal mod list...

Bolt-Ons
ported 14b turbo, ported 1G O2 housing, ported 1G exhaust manifold, Supra fuel pump,AFPR @ 43psi, 1000cc injectors, hacked 2G MAF, shorty 3" exhaust, JMfab smim, ETS 12x3.5x32 fmic

EMS
EPROM ECU with my own custom chip, laptop withTunerPro RT, Ostrich, Pocketlogger, MMCD, and Pocketdyno with custom MPG function, SAFC

Engine
Wiseco 9.0:1 pistons, 85.5mm bore. Eagle rods, crank scraper. ring gaps- .0019" top, .0023" second Ported 1.6L DOHC head, Cometic HG, ARP headstuds @85 ft.-lbs, Crower springs, SS valves, FP2 cams.

Drivetrain
PTT twin disc clutch with Isuzu slave cylinder, Quaife front diff, 4 spider center diff, EVO3 first gear, double syncros on 2nd, 3rd, and 4th gear.

Suspension
Koni shocks/struts custom coilovers with 8"x 300# front springs, 7" x 375# rear. no sway bars. Modified DME rear camber kit, OEM big brakes, R4S pads, SS lines. manual steering, 16x7.5 300z wheels Kumho MX 225/50x16 for street use, and 15x7 Rota Slipstream with 225/50x15 BFG Drag radials for track use.

 

[Bud92gsx]

Bolt ons, injectors, fuel pump,fmic,exhaust.. etc..

Not a built longblock car, nahh meen?

I'm seeing the dyno numbers on the site.The two or three in the lead, one was using race gas.But the common theme here as far as injectors is go big or go home..Why am I just noticing this

 

[gofer]

A built long block isn't necessary in pneumo's build and he did 300+ with the 14b, that's what I'm trying to tell you. Any build with a 14b in the mix doesn't require a built longblock unless you plan on spraying...