Heres my dillema, Im not sure if i should turbo my motor, or build it up.
Heres what i have;
-40,000 mile 225
-Dual Webber Carbs
-Split headers
-Dual 2" exhaust w/ 40 sereis flowmasters.

Should i sell my Webers and headers, get an offy w/ a 4 barrel, modified exhaust manifold, T-bird turbo, MSD ignition.

or

Ported and polished head, mopar .528" lift cam, keep the webers and headers, 198 rods, 2.2 pistons. Maybe nitous?

I think the turbo motor might be cheaper, even though its like starting over parts wise.

I believe this is pretty much a personal choice issue. You can make lots of power either way. In my mind, the turbo involves more unknowns, and is less tried and true, but of course that can be attractive as well.

You could also just put the big cam and head on your bottom end and go with that. That's probably where I'd start, if you feel your bottom end is solid.

One thing about that Offy 2X1 manifold is that I don't think it works too well with high RPM. I have only run 1bbls (BBS and 1920) on this manifold, so I may have been limited by CFM, but when I have switched from that to a Clifford or Offy 4bbl with either a Holley 500 2bbl, or Edel 500 or 600, I went faster and the engine made power a lot higher up. The most dramatic was from the Offy 2X1 with 1920 carbs to the Clifford 4V with 600 4bbl. I picked up about 0.6-0.8 sec in the 1/4 (15.7 to about 15.0), and the engine went from about 4500 RPM top power to 5500+.

Of course, who knows what will happen with a turbo?

Happy building,

Lou

Im thinking of going the turbo route so i dont have to spend the money on getting a head reworked, cam, etc.

I think im going to sell my Webers if favor of a clifford or an offy and Holley or Edelbrock carb.
What is the best combo?

I dont think the turbo will involve too many unknowns, if i get the right carb/intake it will take alot of those unknowns out of the picture.

Still deciding,

Tom B



tommyb1515@aol.com

You're looking at two motors with quite different personalities. The turbo, if done right, will behave like a mild 318, with around 1 horsepower per cube and well over 300 lb-ft of torque. It'll make the torque at a street-friendly 3,000 RPM to boot. It'll idle like a stocker and work well with your stock driveline - except a 7 1/4" axle's days will probably be numbered behind it.

The naturally aspirated motor is likely to make a bit more power, but have a less streetable torque curve. I'd expect you to have to rev it to over 6,000 RPM (possibly 7,000) to get the 250 or so ponies it makes. And it'll make less torque than horsepower. This will be a high strung motor and not the most streetable thing. Don't drive it with an automatic and the stock converter, or any gear ratio numerically lower than 3.91:1. You'd probably want a 4,000 RPM stall converter, to give you an idea of how this thing would drive on the street.

Matt

Ummmm.... the turbo motor is interesting but it will take lot's of custom fabrication work and a bunch if sort-out time to get right. To bad there are no turbo "kits" out there. (as of yet)
The key to long term turbo success is low compression (8 to 1) and strong pistons.

As for the "Hi-Po" motor, this is pretty much a bolt it together deal. Carb, Cam, Compression, Exhaust and Headwork, Headwork, Headwork...
You can get good results either way but my guess is that the turbo set-up would be the "crowd pleaser" just because not many are out there.
DD

I'm building a turbo engine (but it's a 360) for the torque (can you say 530 ft/lbs?). A turbo engine will require fewer drivetrain changes to make use of the added power as it doesn't significantly reduce low end torque. For instance I'm going to use a higher stall torque converter only because I'm using a hotter camshaft. The rear gears are going to be 2.76s and I'll still be able to light up the tires through 3rd.

I am going to be blowing through a Carter AFB with larger needle and seat assemblies using a Turbonetics carb hat (available from Turbo City) and a boost referenced mechanical pump. With the big engine I'm also upgrading to 1/2" fuel line and 90 GPH race fuel pump. You should be able to get away with 3/8" fuel lines, but the stock pump won't keep up over about 200 hp according to a guy that turboed his 225 using the stock pump. Running lean is the surest way to kill a turbo engine so make sure the fuel system is up to the task. If the mechanical pump doesn't keep up about the only thing to do that really works is a high pressure electric pump with a boost referenced BYPASS-type pressure regulator. It's more difficult to use a Holley vacuum secondary carb as the secondaries won't open unless you do a number of modifications. Carter/Edelbrock carbs are easier and don't have the bog problems of the Holley double pumpers. The stock Carter floats don't collapse from boost until 22 psi so don't worry about those.

To summarize, use a Carter/Edelbrock carb jetted richer (use Edelbrocks recommendations for street supercharging), a Turbonetics carb hat from Turbo City, upgrade your fuel lines to 3/8" and send boost from the top of the carb to the spring side of fuel pump to increase fuel pressure with boost. I could go on and on here, but I don't have the time. Read Turbochargers by Hugh MacInnes and then read Maximum Boost by Corky Bell.

Joshua Skinner


joshuaskinner@attbi.com

It looks like im going the turbo route, i donmt like reving my engine to the moon to get alot of power out of it.

Heres what im looking at in the book;

-Offy 4-barrel intake
-Edelbrock 500? or 600 CFM Performer Carb
-Holley 110 GPH 14 psi "blue" fuel pump
-MSD 6A Ignition Box
-MSD Boost Timing Master w/ Vacum Advance

Heres whats not in the book.

With a modified stock exhaust manifold, 86 turbo coupe turbo, volvo? intercooler, 3/8" fuel line 5/16 return, stock electronic distributor, 2.5 exhaust w/ y-pipe to current dual 2" exhaust.

Let me know what you all think of my "Setup"

And heres a few more questions;

-Should i run a 500 or 600 edelbrock carb?
-Should i install an engine oil cooler?
-What fuel regulator should i use?
-What intercooler should i look for?
-Should i leave the stock cam, or?

Thanks everyone for all the advice, Tom B



tommyb1515@aol.com

Intake is fine, but the Clifford may make a little bit more power. Anyone know for sure?

500 CFM is plenty of air. You really need a higher pressure pump. 14 psi fuel pressure is only good to about 10 psi boost with a base fuel pressure of 4 psi and I'd run a base fuel pressure of at least 5 or maybe even 6 psi. You don't really need the 6A box if you use a Mopar Orange box with a good coil. The boost timing master is good for running on pump gas and tuning for economy as it will allow more timing at part throttle.

I'd use a manual transmission Thunderbird Turbo Coupe turbocharger if you can find one. A Volvo turbo would also work well. A 2.2 Mopar turbo can be used, but limits the HP to about 200-220 due to the small compressor. I have 2 T-Bird turbo intercoolers on the shelf and they look pretty good. Got them off eBay for less than $50 each. I think it would be hard to find space for the giant Volvo intercooler. Turbo II Dodge intercoolers are pretty decent, but I was able to find the Ford ones easier. Make both fuel lines 3/8" as almost all the of the fuel pumps capacity is being returned to the tank at idle and light load. Use a Mallory 4309 fuel pressure regulator $74.95 at Summit. Use a big fuel filter too. I like the giant Fram HPG-1.

Change the cam if you want to move the power band up a little and make some more power. If your cam is stock you'll still be turning only slighlty higher than stock max RPM. A small cam like about 252° duration will make a big difference in top end without killing too much low end. An engine oil cooler isn't really necessary unless you're going to drive under boost for more than a minute at a time. You should get through the 1/4 mile in 15 seconds give or take so no need for an oil cooler at the strip. Road racing is another story.

Joshua Skinner

joshuaskinner@attbi.com

Thanks for the help Joshua,

I never thought about the return side having low pressure, but it makes perfect sense. Im thinking if i should run a MSD or Mopar ignition, but thats up to me i guess.

Probally going to a comp cams 252 cam/lifters. I didnt know the Volvo intercoolers were so big, i want the biggest one i can fit in front of the radiator.

If anyone wants to sell me a turbo, intercooler, or any of the parts i need, send me an e-mail.

Thanks, Tom B

tommyb1515@aol.com

No problem.

The Volvo intercooler isn't that great. It's big (bigger than your radiator) so it's hard to fit into the car and it's more restrictive than the Turbo II intercooler and the Ford (Turbo and Super Coupe, SVO, etc.) intercoolers. If you want a big intercooler use 2 or 3 Dodge or Ford intercooler cores with custom tanks. The facory electronic ignition is good. With good plug wires and coil it will light the fire quite reliably.

The 252 comp cam should work great. Comp Cams seem to be a bit noisy, but I don't mind myself. I destroyed my Comp cam and had Oregon Cam Grinding make me a cam to my specs that ended up being quieter.

Go wrecking yard hopping for the turbo and keep an eye out for intercoolers. And don't forget about eBay, but don't pay too much.

Joshua

joshuaskinner@attbi.com