Size a budget built turbo small block.

So I am actually starting to put together a turbo setup for my small block, beofre i get in to deep can someone help me size a proper turbo for a 360 ill make sure to have a good dished forged piston a mild efi/turbo specd cam and good rods. The car will be a 73 duster with a 904 and a 8.75 with 3.23 gears. depending on what the registration comes to (as the car was junked at one point) I plan to build it into a competitive street strip car but may be race only. The classes in my area have a restriction of a 76 mm turbo and the racers in that class are running in the 5.50 range 1/8th mile so im assuming i wont be competitive here may be a fun bracket/grudge car. I currently have a log setup that has a t4 flange and is setup for a 38mm wastegate which im hoping i can use but im afraid of boost creep. Any advice would be appreciated. I would love to go MS3 and coil near plug like my street big block car but such electronics aren't allowed in the OSCA class to my knowledge, so likely it will be a blowthru 750. Thanks in advance.

Hard to beat a Borg Warner s475, T6 flange, 1.32 ar

I've got just over 3k in my setup, and that includes a $1000 csu blow through carb who i aabsolutely recommend. Did everything my self. T6 s475, twin 38mm wastegates, 2.25" hotside on a 400"ish sb. 137 mph @ 3550lb on 10lbs. Fixing to turn it up and run a local 8.5 tire class here soon.


My advice is to no buy cheap parts especially wastegates I've heard alot of horror storys.

Looks good, do you use meth/water injection?

We have a member here with a small block turbo car who is intending to build exactly such a kit.
I would guess he will see this thread at some point.

Nope. Blow through e85

I think the kits are built, he is just testing before making them available....I am waiting patiently to see what happens with them, as my 408 is coming out this winter for a refresh- if the kits are available, it might just be getting some new pistons and turbo cam along with one of the kits

Yes still working on the kits. The last few months have been focused on getting mine back together with my old setup so I could race while I keep working on them!

To the original poster... how much power and/or how much do you want to spend on the turbo. That will go a long way in determining what turbo you need.

There are $400 75mm turbos, and $2000 75mm turbos.

If you have a stock block, 904, and 8 3/4" I'm guessing you're not looking for max effort.

The S475's (1.32 A/R, T6 Flange) can be had for under $700 and will make just over 1000hp. Pretty good bang for the buck on a small block. They are pretty big/bulky though, and there are other options.

There are some other "offshore" turbo's that can be had in the 75mm range in a T4 flange that are a little cheaper and will spool better, but won't make the power of the S475.

If you want to make less power, you can get something that isn't rated for that power level, but will spool better.

If you want more power, that can be had for more money, but I'm not sure how well the stock block will like it.

My advice is to set a realistic budget, base some realistic power goals from that, and stick to that plan when you start buying parts.

No sense in putting a $2000 turbo that will make 1400hp on a $100 block.

Your in Kentucky, we have some good turbo guys in state. LJMS Little John motor sports is a sponsor of turbobullet.com. he's in Smiths Grove down by Bowling Green.

The OSCA is where I would like to run but the weights a turbo big block has to run at are to heavy. There is a turbo mustang that's fast but I have not been to a race this year to see what else is out there.

Thanks Fast I'm about an hour north of bowling green. Dizuster I understand that I'll have to step up to run big numbers I'm just starting with what I have. I'll have to go with a spare 727 or a th400 and a 9inch. The R3 block isn't in the budget for now maybe down the road. Here's the class rules for turbo cars. I also have to weigh in at 3300 seems pretty tough for a turbo car to compete with nitrous cars that can weigh 200 less. Im not sure what power level I'll need but if I can't get close to the 5.50 eighth mile range I'll just build a street/strip bracket car!

FORCED INDUCTION:
Single turbo or blower on all combos
No billet wheels allowed
Max turbo size 76mm measured tip to tip. (no reducers allowed to achieve
this size and no clipped wheels)
You may be required at any time to remove your turbo and/or your turbo
cover to be checked.
Maximum supercharger sizes D1, V-7 JT Trim, NOVI 2000, Kenny Bell 3.6
allowed with weight
Air to water, Air to air intercooler OR water meth injection allowed.
Can only run 1 style intercooler
Boosted cars no boost controllers allowed of any kind. No solenoids on car.
Line ok going from top of wastegate to intake manifold(only), Nothing inbetween
Nothing else to top of wastegate or blow off valve
Driveshaft sensors or output shaft speed sensors to external data
loggers ONLY. Can not go to ECU. Traction Control of any kind prohibited!!!!!

Turbocharged (mid frame turbo only) and supercharged entries are limited
to stock valve angle SB combos only. SB CHEVY 23 DEGREE - SB FORD 20 DEGREE - 18
DEGREE MOPAR - FACTORY HEADED SMALL BLOCK FORD MOD MOTOR - LS CHEVY Heads listed
above ONLY!!CATHEDRAL PORT ONLY
No raised runner heads permitted on boosted application
No Co2 in car

I don't think you are going to get into the 5.50 range with an 8 3/4, 904 and stock block, unless you are looking to just make 1 banzai pass.

If you want to get in the 6.50 range, you can do it easily with a "cheapie" 76mm and the combo you want to run. FYI, I run a "cheapie" 76mm T-4.

You must be real close to me. You around Bardstown?
I'm out of piston prison so my junk should be running again soon. I go to the Valley and US-60 mostly. I do hit Beech Bend when everything else closes.
Call LJMS, he's a good guy to run stuff by.

Thanks. I'm actually really close to us 60 takes me about 25 minutes to drive there I usually drive the 70 roadrunner clone up and make a few passes when I have time. As for the 76mm what are you running? I'm looking at picking up something soon. So at what point is a 904 reworked with a lowgear set good clutches MVB and possible brake going to become a problem? Also what's the limit on a 8 3/4 I'm going to have to but this one down anyway just already have the parts.

I don't think you'll get a stock block to go 5.50's. The problem is that is uncharted territory. There are not a lot of turbo small block mopars out there, so it's really hard to judge how much power the stock block will take.

Mine makes around 800hp, but it's shown some signs of block fatigue (odd main bearing wear from flexing, excessive blow by under boost requiring puke tank, etc...) Mine is filled, and even has a girdle on it now, but I'm not sure how much more power it would take. There are some very fast stock block ford/chevy examples out there though, and I don't think the Small block mopar is any worse then a 350/351 combo.

Here is my story so you can see if it helps you.

Started with a cast crank/stock block/stock rod/forged shelf piston combo with iron heads, transbrake 727, 8 3/4, S475 turbo running through stock dodge ram manifolds.

First thing it broke was the sprag in the trans, it even had a low band apply valve body. Upgraded to super sprag, replaced warn clutches because some of them were hot looking (stock clutches). This was at the 10.60~10.70 range.

Then I kept turning it up... went from 10.60~10.20's pretty easily.

Turned it up looking for 9's. 10.08@136 on 20psi. Next pass all hell broke loose.

Sheared the pinion off the 8 3/4" at the starting line. Had to replace with a Dana 60.

Took the trans apart, and the front planetary was 1/2 ripped out (unknown if it happened before or during the gear break). Needed a planetary, new direct drum (again old one had hot clutches even with Alto's).

Took the motor apart to put better rods in it, and found 3 of the 8 pistons caved in. Not melted through... just overpowered. Found that the bottom end had some weird main bearing wear attributed to the block/crank flexing, so I put a girdle on it. Every pair of valves had a crack between both cylinders, so I had to put heads on it.

Since with the better heads, it's been 9.88@138 on 15~16psi. (Which equates to 6.31@110 if you're wondering).

So just from my experience no where NEAR 5.50... I'd be leary of trying a 8 3/4 and 904 combo.


That being said... if you're looking to use what you have, I see no issue with building a lower powered combo to get your feet wet, and stepping up.

Put a cheap T4 turbo on it, and build yourself a good hot side. That way later when you want to step up on power, you can just replace the turbo without having to rebuild everything else.

Low 10's in an a-body could be done fairly low cost, and be fairly reliable.

I would put one of the offshore lower cost turbo's on it. Either the GT45 80mm, or the 80/75. Build yourself a 2.25" hotside, and let it rip.

IMG_20140723_183648_773

[quote=dizuster]I don't think you'll get a stock block to go 5.50's. The problem is that is uncharted territory. There are not a lot of turbo small block mopars out there, so it's really hard to judge how much power the stock block will take.

Mine makes around 800hp, but it's shown some signs of block fatigue (odd main bearing wear from flexing, excessive blow by under boost requiring puke tank, etc...) Mine is filled, and even has a girdle on it now, but I'm not sure how much more power it would take. There are some very fast stock block ford/chevy examples out there though, and I don't think the Small block mopar is any worse then a 350/351 combo.

Here is my story so you can see if it helps you.

Started with a cast crank/stock block/stock rod/forged shelf piston combo with iron heads, transbrake 727, 8 3/4, S475 turbo running through stock dodge ram manifolds.

First thing it broke was the sprag in the trans, it even had a low band apply valve body. Upgraded to super sprag, replaced warn clutches because some of them were hot looking (stock clutches). This was at the 10.60~10.70 range.

Then I kept turning it up... went from 10.60~10.20's pretty easily.

Turned it up looking for 9's. 10.08@136 on 20psi. Next pass all hell broke loose.

Sheared the pinion off the 8 3/4" at the starting line. Had to replace with a Dana 60.

Took the trans apart, and the front planetary was 1/2 ripped out (unknown if it happened before or during the gear break). Needed a planetary, new direct drum (again old one had hot clutches even with Alto's).

Took the motor apart to put better rods in it, and found 3 of the 8 pistons caved in. Not melted through... just overpowered. Found that the bottom end had some weird main bearing wear attributed to the block/crank flexing, so I put a girdle on it. Every pair of valves had a crack between both cylinders, so I had to put heads on it.

Since with the better heads, it's been 9.88@138 on 15~16psi. (Which equates to 6.31@110 if you're wondering).

So just from my experience no where NEAR 5.50... I'd be leary of trying a 8 3/4 and 904 combo.


That being said... if you're looking to use what you have, I see no issue with building a lower powered combo to get your feet wet, and stepping up.

Put a cheap T4 turbo on it, and build yourself a good hot side. That way later when you want to step up on power, you can just replace the turbo without having to rebuild everything else.

Low 10's in an a-body could be done fairly low cost, and be fairly reliable.

I would put one of the offshore lower cost turbo's on it. Either the GT45 80mm, or the 80/75. Build yourself a 2.25" hotside, and let it rip.
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I know where're talking LA stuff but I have a good stock 5.7 sitting here, would the same parts,ideas, work for the it?

Hemi with a 6.1l crank, and good rods pistons will go a LOT further then an LA.

I will build a turbo Gen 3 HEMI next for sure.

I have a stupid question: Exhaust on a turbo motor is out the front/side I notice. Are turbo combos quiet enough that they're run open (no muff) for street driving??

Can someone post a vid of a track run, or a street cruise with a little a stab of the pedal or two??

What's a "cheapie" turbo??

What converter and gear are you running?

Diz...what about your converter and gears?

Any pics of your motor you care to share?

Thanks!

dizuster has a great driving around vid. Hope he posts it for you !

My car has a PTC 9.5" converter in it. They make a REAL nice one that works for moderate power for about $475.

I run a 3.55 gear in a Dana, but my car went 10.60's before with only a 2.76 gear in it. You don't need a ton of gear.

Here is the vid...

https://www.youtube.com/watch?v=vqJoG_2wdMQ

Same answer on mine as Diz...

Dizuster and other dodge, how much compression is too much? With forged I beams and forged pistons 9.6-1 with good quench with an air to water intercooler on 93 or race fuel mix (as e 85 isn't available here) possible? Obviously locked timing around 12-15...

9.6:1 isn't too much at all. You will be boost limited on pump gas, but on race gas you'll be totally find with a decent intercooler.

Timing will just depend on what fuel you have in it, and how much boost you run.

I ran as much as 26 degree's on 20psi with non-intercooled E85, with iron heads at 9.2:1.

You won't want to lock it at 12 for sure, it will drive awful off boost. Need to have something that pulls timing as boost increases.

Thanks my holley pro strip ignition has a boost retard feature so that should do it if i dont go ms3

Anyone have a good recommendation for ring packs?

Put the top ring as low as you can...

I went with a stainless top ring on Total Seals advice.