How driveable is a drawthru on the street?

Scotty C · Post by **Scotty C** » Tue Feb 11, 2003 1:05 pm

I drive my beetle every day and alot on week ends. Can I drive it for an hour or so?
The guys I work with say it will not be very responsive when it isn't under boost.
I still plan on trying it but wonder if I should only run it on a drag only car?
I have a t3 chrysler turbo
1641 /ported stock heads
390 holley
I plan on running a deltagate and only 7psi.
I was just wondering ?

69bug · Post by **69bug** » Tue Feb 11, 2003 3:26 pm

people say its good if set up right...but blowthru is better always

i've heard

JoeSumen · Post by **JoeSumen** » Tue Feb 11, 2003 4:30 pm

<BLOCKQUOTE>quote:<HR>Originally posted by Scotty C:
I drive my beetle every day and alot on week ends. Can I drive it for an hour or so?
The guys I work with say it will not be very responsive when it isn't under boost.
I still plan on trying it but wonder if I should only run it on a drag only car?
I have a t3 chrysler turbo
1641 /ported stock heads
390 holley

I plan on running a deltagate and only 7psi.
I was just wondering ?

<HR></BLOCKQUOTE>

Scotty,
Draw Through systems can perform very well..

Just as any turbo, (or normally aspirated for that matter), system though, regardless of fuel delivery, tuning is required for proper all-around operation...

In the ACVW racing community, there are MANY folks using a 4bbl Holley... I really don't believe that for everyday purposes such as yours, they're the way to go... I can't even imagine how drunk and slack-jawed they must feel down low, at lower revs when not under boost..

Also, I'm pretty certain ambient temperatures up in Ontario even on pleasant days in the fall/winter must be pretty low...
Draw throughs are absolutely horrible in cold weather...

For your application an SU would be the best by a HUGE margin...I mean HUGE...You can see more on this type of carb set up further down in the SU vs, Fuel Injection thread..

Joe
Moore Racing/
Moore Part Source

[This message has been edited by MOOREPARTSOURCE (edited 02-11-2003).]

volksnut · Post by **volksnut** » Tue Feb 11, 2003 6:25 pm

well I've run 4 different carbs on my car to date (if you don't know by now it's the same size & set-up as yours)..In the begining I ran a 40 DCNF (because I was waiting on parts for my DCOE), it ran real well (8.60 in 1/8th mile @ 5#'s boost) but I was new to the game and didn't give it enough seat time, I then installed the 45 DCOE (with new parts cause I bought a empty carb....that's another story in it's self) it ran well too (9.30 in 1/8th mile @ 5#'s boost) but was to big for my little motor ...then I went with a Zenith 32 NDIZ with 28 venturies (it ran great, ran the best of 12.3 in 1/4 mile @ 10#'s boost) but the poor thing had worn throttle shafts etc. so it was a time for a change. OKAY now with the present, As you all know I changed to a SU carb (I also liked the look of a sidedraft on a turbo

) and after getting educated

on it, it is now running flawless....I must say it's now ready to run it at he track. I'm going tomorrow night so I'll let you know how it does. Keep in mind I have some HEAVY steel wheels on the rear (had Centerlines before) so comparing apples to apples will have to come later when my ERCO's come in, I do have the fronts but the rears are on order. Til then

Joe vw · Post by **Joe vw** » Tue Feb 11, 2003 6:31 pm

I was surprised how good the drivability is with my home made 1600 j-yard turbo set up.
After hearing how bad it would be with a draw through from things I've read. But then there's people with bad combos out there that spread the news. It's not completely perfect, but very good considering I haven't had enough time to really tune it due to the cold. I was surprised how well it ran even in cold weather, it has a choke too.
I have a small Weber progressive on mine with the same turbo you have. It is more than enough for a 1600 don't be fooled thinking bigger is better. I would like to get my hands on an SU now after hearing good things about them too.

panel · Post by **panel** » Tue Feb 11, 2003 8:05 pm

<BLOCKQUOTE>quote:<HR>Originally posted by Scotty C:
I drive my beetle every day and alot on week ends. Can I drive it for an hour or so?

<HR></BLOCKQUOTE>I drove mine down to Seattle one weekend and thats longer than an hour drive.Also last summer had a three day VW weekend in Vancouver drove it to Mission Raceway a way longer the 1hr trip and then did 3 passes in the 1/4 mile with her. Drove all over the place Sat and all the way back Sun to the ferry and then another hour or so to home.Plus this is my daily driver in the summer to work and back all the time.So yes you can drive it more than an hour!

------------------
Check out my web site here

JoeSumen · Post by **JoeSumen** » Tue Feb 11, 2003 10:58 pm

Here's "Volksnuts" link...So you don't need to leave...
http://community.webshots.com/album/61799611ivQsSr

This by FAR the method I suggest for those of you who're searching for great overall performance on your street driven vehicles...

Joe
Moore Racing/
Moore Part Source
www.mooreparts.com

[This message has been edited by MOOREPARTSOURCE (edited 02-12-2003).]

workingstiff · Post by **workingstiff** » Wed Feb 12, 2003 4:53 am

I have a 1776 t3 in my rail.A couple of years ago my brother and buddy took our rails camping. We drove form the s/e corner of Michigan up to the upper pennisula. Back down the other side of the state and across the bottom. The only problem I had was I broke a ball swivelfoot about a half hour out from the house. All in all probaly 20-25 hrs. I even towed a very small trailer at times. Dan

KG68 · Post by **KG68** » Wed Feb 12, 2003 4:28 pm

I wish that there was more info on the Junkyard turbo buggy site. The pics are pretty though. i like the looks of the polished SU. I would like to know handy things like spring, jet and needle specs and info on modifying needles to provide more flow at certain points in the rmp/boost range. I found a good site on a simple drawthrough SU turbo it isn't vw but is is informative. http://home.att.net/~jason510/turbo.htm

volksnut · Post by **volksnut** » Wed Feb 12, 2003 8:31 pm

I'm updating my site now so it won't be much longer, WELL....I had throttle cable problems at the track tonight, that along with long lines made for a bad night, the cable slipped out and lost the barrel screw...yeah I know I should carry spares...maybe next week. The carb I have is a HS4 which is a 1 1/2" in size or 38mm if your want to be technical....it has a 4.5oz. spring, a modified AAB needle, and .125 needle and seat, and I modified the throttle shaft & butterfly a bit. I 'm running 10w 40 weight oil in the dashpot. When I got the carb it has a ABK needle and I profiled it to a AAB needle to start with since it was the richest needle out there, after I found it worked like I wanted I bought a AAB and touched it up just off idle. The needle has different stations from 1 to 16....1 and 2 being idle, then 3 through 8 is mid range with everything else being top end. There in 1/8th inch increments. Like I said before buy a book and go from there, I like them and they easy to work on, and prices are cheap...i.e needles $14.95, needle & seat $10.00 etc. I would think a 2" SU could support a few hundred horse power, when in doubt... whip 2 of them out

Matt Davis · Post by **Matt Davis** » Thu Feb 13, 2003 12:21 am

I've had both draw through and blow through on street motors. Blow throughs are by far the superior setup for turbocharging on the street but we all run what we got at the time. The current draw through setup I run is in my drag car but when I'm feeling a little balzy I take it a few blocks away on the street. It does run nice all the way through the RPM range and does NOT need to be "on boost" to make decent power at any given RPM. I also believe this is due to the smaller port design and valve size in my heads. It makes good power off idle to just plain old ROMPING on it from either a standstill or rolling start.

------------------
Matt Davis
www.davis-racing.org

MagOO · Post by **MagOO** » Thu Feb 13, 2003 8:45 am

Not to start a range war, but General Motors, who have one of the best R&D departments, coupled with the tightest finacial arm, have seen fit to develope and release draw though turbo designs from BOP as well as Chevy .. They worked to varying degrees, but driveabilty was not a great complaint, only that the hafast, lowbuck approach seriously impinged on the power producing capabilties as delivered.. But you could do a few tricks and the beast would wake right up... In the VW it is fairly easy to get decent results as the turbo almost HAS to be mounted with a downward boost path.. Keep the few principles of turbodom , researched years ago by pioneers such as Mcinnes, Hallock,Miller and others in mind, and you should do OK... But remember the future is probably EFI...

Matt Davis · Post by **Matt Davis** » Sat Feb 15, 2003 12:07 pm

The "future" is EFI? The ONLY reason I have continually run a draw through is because when I was younger all we had was MFI ($$) and carbs. Not to mention a certain sanctioning body would only let the turbo cars run carb's. So I kinda hung on TRYING to get a big enough motor built to go play with them guy's and then they killed the class (P/T) and went to the NOS/Turbo class (P/M) and still only let carbs in for fuel delivery. If this was a perfect world we'd all be running EFI. For crist's sake, it's only been around (EFI) for what like 20 years now mainstream? Wake up! I'd love to toy with some EFI on my drag motor. You could cut down a lot of engine compartment room too with the 4bbl and intake gone. Then you can easily fit the IC in the same compartment.

------------------
Matt Davis
www.davis-racing.org

turbolaz · Post by **turbolaz** » Sat Feb 15, 2003 1:39 pm

i have a draw trough system in my rail it weighs 1450 with me im currenly running a 1776 engine with an engle 120 044 cb heads with dual springs a must 10mm studs,1.1 rockers,11/2 exaust t3-t4 hibrid -s trim-48 exaust a/r weber 40 very tunable with 175 mains 185 airs 30mm vents 55 idles,race fuel for the track @20 lbs boost,ive run an 11.5 with that motor@119mph with a bus tranny with 4.57 r&p,for all that are trying new combos,runs great in the street can run forever no overheating,in fact quite cool,hope i can be helpfull with all the questions on drawtroughs,lazaro from miami.

[email protected] · Post by **[email protected]** » Sat Feb 15, 2003 2:24 pm

damn, all you turbo guyz in FL are killing me, I was just in FL and diddn't see a single VW. Turbolaz, do you have any pics of your setup? This is tons of good info, thanks volksnut on the SU stuff, what is the best book out there for modding the carb? I plan on running one in my street bug. It's a daily driver, so the SU sounds like the perfect carb for me. I just found a Turbo T-bird and a Daytona at the Junkyrd, so when it stops raining in Nor-Cal, I can start working it out.