Speed-O-Motive

[1Gary]

Speed-O-Motive has been in the business of building engines as long as I can remember and I am one of the elder hot rodders.

I came across the link I am going to post while looking for a 3.75 stroker 4.3 kit to show a alternative to a V8 swap for guys the God knows how many times we have hear of a rod knock that developed and they would be buying a lower end kit anyways to rebuild their engine.Here is that info:

http://www.speedomotive.com/ps-502-81-4 ... k-kit.aspx

When you consider you end up with a more powerful V6,the price of about $1,500 really isn't that bad.

So I am poking around their web site and I think I found a outstanding article about engine building with a lot of info about a whole host of topics.Kind of a bible of engine building.You'll see the start of it below the spec sheet towards the bottom of the page.I bookmarked it and I am suggesting you guys do the same.Here is the link:

http://www.speedomotive.com/t-showbymodel.aspx

[chartman]

If i could do it over again id turbo the 4.3l instead of putting in the v8.

[leadtrombone]

Pray tell. why..???

Just curious. V-8 Vs V-6 with more power... Hmmm

[Meterpig]

If i could do it over again id turbo the 4.3l instead of putting in the v8.

That's a lot of extra plumbing for turbo. Not to mention the various settings you need to change to run it.

[Kidhauler]

There is no replacement for displacement. Turbo the v8 and go camaro hunting.

[loopie]

Nice find Gary. Ya, if a guy already has the v6 opened up for work and needs a crank...good option. Gotta be dedicated to the v6 tho as dollar per HP is way higher than what a v8 will yeild, but I suppose we all know that.

[chartman]

"Gotta be dedicated to the v6 tho as dollar per HP is way higher than what a v8 will yeild, but I suppose we all know that"
No true. Two words...Syclone & Typhoon
http://www.youtube.com/watch?v=HnQn54UNDxE

I race so i understand engines....I've also had two v8s in this truck so i speak from experience regarding the swap per power gained vs price of swap vs gas mileage lost.

"No replacement for displacement" - this ONLY applies to naturally aspirated engines.

A turbo engine CAN make more power either down-low or up-top....your turbo selection decides. I don't run my truck engine at RACE RPMS, so why do i need peak power at 5000 + RPM like my naturally aspirated v8s? You don't if you drive the van. I need it at around 2,000 rpm in 4th gear pulling a trailer. Take a look at the Ford F-150 mildly tuned v6 Ecoboost. It makes around 400HP and 400ftlbs of torque (at low RPMS). If gas mileage wasn't an issue, Ford could have the numbers off the charts....more fuel + more oxygen = more power.

http://www.ford.com/trucks/f150/experiencef150


If i had to do it over...and i may, Id keep the v6 and would make the Astro into a Syclone / Typhoon and call it a day. Thanks for the above v6 links Gary.

[1Gary]

Honestly,I don't know.The turbo's that where in the S10's.You don't find that many of them around.Is it a matter of people are keeping them as a collector item or is it a matter of a problem with the engines that was found??.Maybe someone could chime in with what the history ended up to be.

[chartman]

.Maybe someone could chime in with what the history ended up to be.

Both the GMC Syclone and Typhoon (SyTy) trucks featured a Mitsubishi TD06-17C/8 cm2 turbocharger and Garrett Water/Air intercooler attached to a 4.3 L LB4 V6 intake manifolds, fuel system, exhaust manifolds, and a 48mm twin-bore throttle body from the 5.7 L GM Small-Block engine. All SyTy's had a GM 700R4 transmission (4L60) 4-speed automatic transmission and a BorgWarner 1372(Syclone)/4472(Typhoon) transfer case splitting torque with 35% forward and 65% to the rear wheels. Both trucks featured all-wheel drive, upgraded brakes, and sport modifications to the standard suspensions. Unlike the Syclone, the Typhoon featured an air-operated self-leveling rear suspension. Output was officially 280 hp (209 kW) and 360 ft·lbf (488 N·m), but some stock Typhoons have been measured at over 300 hp (224 kW) on a dynamometer.

The Typhoon was capable of accelerating from 0-60 mph in 5.3 seconds and could do a quarter-mile run in 14.1 seconds at 95 mph (153 km/h). Car and Driver was impressed, comparing the Syclone's performance favorably to the Ferrari 348ts, Chevrolet Corvette, and Nissan 300ZX Turbo. It cost US$29,970, though the magazine criticized the plasticy interior pieces.

For Engine info
Taken from http://www.syty.org/old/faq.html

Engine Specifications
Here's the master spec sheet from the manuals:
GENERAL
Type: V6
Disp.: 262 C.I. (4.3L)
Horsepower: 280 BHP @ 4400 (Syclone) 285 BHP @4400 (Typhoon)
Torque: 350 lb-ft @ 3600 (Syclone) 350 lb-ft @ 3600 (Typhoon)
RPO: LB4
Bore: 4.00
Stroke: 3.48
Comp. Ratio: 8.35:1
Firing Order: 1-6-5-4-3-2
Oil Pres. (Min) 6 psi@ 1000 RPM, 18 psi@ 2000 RPM, 24 psi@ 4000 RPM
CYLINDER BORE:
Diameter: 3.9995-40025
Out of
Round: .001 (production) .002 (service)
Taper: .001

PISTONS:
Clearance: .0015-.0030
PISTON RING: Compression: Groove Clearance: .0012-.0032 Gap: .010-.020 (top) .010-.025 (2nd) Oil: GC: .002-.007 Gap: .015-.055 PISTON PIN: Diam: .9270-.9273 Piston Clearance: .0002-.0007 Rod Fit: .0008-.0016 Interference
CRANKSHAFT:
MAIN JOURNAL: Diam: #1 2.4484-2.4493
#2 #3 2.4481-2.4490
#4 2.4479-2.4488
Taper: .001 max
Out of Round: .001 max
MAIN BRG. CLEARANCE: #1 .0010-.0015 #2#3 .0010-.0025 #4 .0025-.0035
CRANK END PLAY: .002-.006
CRANKPIN: Diam: 2.2487-2.2497
Taper: .001 max
OOR: .001 max
ROD CLEARANCE: .0013-0030
SIDE CLEARANCE: .006-.014
CAMSHAFT:
LIFT +- .002 Intake .357 Exhaust .390 Journal Diam: 1.8682-1.8692 End Play .004 -.012
VALVE SYSTEM:
Lifter Hydraulic Rocker ratio 1.5:1
Lash Adj. One turn down from zero Face Angle 45 deg.
Seat Angle 46 deg.
Runout .002 max
Seat Width 1/16 to 1/32 Stem clearance .0010-.0028 Spring length 2.03 Valve Spring Pres. 76-84 lbs @ 1.70 in Closed 194-206 lbs @ 1.25 in
Open Installed height 1 23/32"
Valve Spring Damper: Free Length 1.86 # coils 4