[JarZ]

From Stu:

Well, most of the V6 guys know I've been working on a 3.5 stroker engine. This first one will be just over 4.0 and is going together with CP pistons, Arrow rods, CNC ported heads which will be available and I will have pics of next week and a substantially bigger set of cams with high lift premium valve springs and crower retainers and larger manley valves.



Here are some pics of the pistons and rods. The block is back from the maching shop and I'm cleaning it up before shooting photos. The crank is done being offset ground and is being ballanced now. So were about 3 weeks out on having it done. Here are some initial pics.

 

[JarZ]

more eye candy

 

[Five.SevenlExpress]

any updates on this jarz/stu?

 

[JarZ]

Per Stu:

Well it was looking like the dyno was going to have to happen Sat but at 3 they called me to get over there ASAP because they werent going to dyno the 472 Hemi roadrunner today.

Sooo, after 3 hours of whacking on it with the dyno and tweaking we got 277 HP and 273 TQ. A little shy of what I wanted but sill about 100 HP over stock and about the same as a stock RT. The engine has 325 in it but it's going to have to have a TCM that will let it go to 7000 RPM without shifting up because it was still climbing pretty good at 6300 where it shifted. Another thing I noticed is the pratio (ratio of atmospheric to manifold pressure) was about 0.91 so there is some serious restriction in the intake which is probablly the throttle body and the upper intake manifold. They are both pretty small in cross section for this power level. I think a different upper intake with an 80 mm hemi TB would do wonders since most heims are at 1.0 on the pratio which means minimum intake restriction before the map sensor. Probably just a hemi TB adapted over would get some gains but we won't know till we try.
Sooo, after 3 hours of whacking on it with the dyno and tweaking we got 277 HP and 273 TQ. A little shy of what I wanted but sill about 100 HP over stock and about the same as a stock RT. The engine has 325 in it but it's going to have to have a TCM that will let it go to 7000 RPM without shifting up because it was still climbing pretty good at 6300 where it shifted. Another thing I noticed is the pratio (ratio of atmospheric to manifold pressure) was about 0.91 so there is some serious restriction in the intake which is probablly the throttle body and the upper intake manifold. They are both pretty small in cross section for this power level. I think a different upper intake with an 80 mm hemi TB would do wonders since most heims are at 1.0 on the pratio which means minimum intake restriction before the map sensor. Probably just a hemi TB adapted over would get some gains but we won't know till we try.

I had a feeling the TB and upper intake would be the bottle neck but fortunately the lower intake leaves us with some options to match a fabed upper pretty easy and the hemi TB will work with our drivers for the TB. Well the hemi drivers work on the V6 TB so I think they will interchange.

Not sure why but only the first 6 dyno pulls copied to me the best one was number 12 this is 6 and it's a little down on HP and alot on TQ as we got 273 ft-lb out of it on 12 but it is a taste. I'll try and get 12 emailed to me tomorrow or monday so you all can see the final and best results. Even this shows Mikes baseline he did when he showed up on the same dyno at that point he had the dual exhaust, cai and predator canned tune.

This is not the best dyno but the mods are:

4.0 L stroker with 11.0 cr on 93 octane pump gas
big valve cnc'd heads,
stroker cam
ported lower intake
Ported TB
3500 stall converter

I'm playing around with sleeving to 4.0" so I can do a 4.7 stroker next time.

OH, and I used 6.1 injectors on it. Figured the stock injectors wouldn't do it so I swaped them out right of to batt

The cost for the package was around $6500 without install and tuning. Since this brave fellow risked being a guinee pig on V6 strokers I tuned him for free and gave him a pretty big break on the install and other stuff. As it turned out the 5 day estimate took me like 3 weeks becaue I had a big complication (sheared cam key) so he was pretty patient too. I think it payed off though.

 

[AIR_RAM]

Impressive.. good work! Thats good power from such a small engine. I bet boring it out to a 4.7L would be sick!

SPEED SAFE, AIR RAM