black owned
black pride
- Joined
- Jun 15, 2008
3.8 or 4.1 ?
- Thread starter 007gn
- Start date
Yes hes talking about a production block he says it on the post 8 (I then built the first TA alum block 4.1 and sold the complete production 4.1 engine to an owner in Cali. After a few more years I heard from the third owner who was still running the crap out of it!
)Yes hes talking about a production block he says it on the post 8 (I then built the first TA alum block 4.1 and sold the complete production 4.1 engine to an owner in Cali. After a few more years I heard from the third owner who was still running the crap out of it!
Rude Dog, this question was asked by me and then others and Nick never came back to this thread to clear it up even though he frequents the board. Someone should draw his attention back here to get an answer. I went back and reread it and it is still not clear to me as more than one engine is talked about in this thread by Nick. I myself would not build a production 4.1 to make peak power at 7000 rpm, so would like to hear more about it if someone has.
Take care, Kip
84AireCaliente
New Member
- Joined
- Oct 7, 2012
Nick, can you share cam specs on this motor (or give a run down of all parts) that run 9.80's with 18psi? I building a similar motor, 109, 3.625", billet centers, gn1's, 6765, ta headers. Have not choose cam yet but want to go hyd roller 212 or 218.
- Joined
- May 26, 2001
I would like to address and clear up a few items about the 4.1 in performance and reliability.
As in any engine, the power comes basically from the heads, and the block is there to keep everything together which is why I prefer a 4.1 over a 3.8 for overall street performance, and track use into the 9's.
The bigger bore of the 4.1 can accommodate larger valves, and this bore also allows better flow in and around the valves for better breathing. This provides more low and mid-range torque over the 3.8 which is why GM used them in full-size Buicks and other heavy GM "barges".
I currently have 3 4.1 engines, the protype TA alum block normally in my race car, one production 4.1 used as a spare for the race car with the same TA well ported heads, solid roller cam, Champion intake as the alum block, and a milder street build with iron heads and a hydraulic roller cam replacing a 3.8 in my E-85 street toy.
All builds are 3.625" stroke, and all the same type forged rotating parts.
With a 70 mm turbo and shifting at 6600, the race car will run 9.80 to 10.0 at 18 psi on Sunoco 116 octane with either engine, alum or production block.
I have yet to see a 3.8 build match that performance, except when using more boost and RPM?
We do many 4.1 builds and currently have 3 in process plus one just finished to be picked up this weekend. We have done 4.1 builds for over 15 years and have yet to see one of these "weak" blocks break in a critical area
As in any engine, the power comes basically from the heads, and the block is there to keep everything together which is why I prefer a 4.1 over a 3.8 for overall street performance, and track use into the 9's.
The bigger bore of the 4.1 can accommodate larger valves, and this bore also allows better flow in and around the valves for better breathing. This provides more low and mid-range torque over the 3.8 which is why GM used them in full-size Buicks and other heavy GM "barges".
I currently have 3 4.1 engines, the protype TA alum block normally in my race car, one production 4.1 used as a spare for the race car with the same TA well ported heads, solid roller cam, Champion intake as the alum block, and a milder street build with iron heads and a hydraulic roller cam replacing a 3.8 in my E-85 street toy.
All builds are 3.625" stroke, and all the same type forged rotating parts.
With a 70 mm turbo and shifting at 6600, the race car will run 9.80 to 10.0 at 18 psi on Sunoco 116 octane with either engine, alum or production block.
I have yet to see a 3.8 build match that performance, except when using more boost and RPM?
We do many 4.1 builds and currently have 3 in process plus one just finished to be picked up this weekend. We have done 4.1 builds for over 15 years and have yet to see one of these "weak" blocks break in a critical area
I just went through the same experience. My 109 bit the dust a year ago and was unusable so I bought a virgin complete 4.1 291 block due to all the "cheap power 4.1" threads and articles. I tear down the motor (which did have a rolled fillet crank) take it to the most popular shop for GNs in my area...and they turned me down saying they cant guarantee the 4.1s due to the large volume of customers that have had issues with them. I was pissed to say the least so I called 2 local gurus on buicks (dick walker and tracey hooper) to find a new shop to build it...they both told me to go 3.8...and both had previously ran 10 second 4.1s. Basically they said head gaskets were a major issue with them. They ran as fast as a 3.8 with much less boost, but will not take the higher levels of boost the 3.8 will.
I bought a 109 block from tracey for $50, used the crank outta the 4.1 (my 109 crank snapped into 3 pieces) and sold the rest of the 4.1 stuff. Just got my short block back from the machine shop and almost ready to put it back in. I would say if your 109 block is in good shape don’t even consider the 4.1.
turbonut85
Rarely used member
- Joined
- Apr 11, 2008
I'm running a 4.1 production block in my (minimum) low, low, 11 second HOT AIR car on E85 at 23 psi....has held up beautifully. I would not shy from the 4.1's....don't knock em til you try em. If there was anyone (engine wise) on this board that a person should listen to...it's Nick.
Thankyou for all of your replies . I've since did the 4.1 thing . My motor is done & will be in my super beautiful car in the next 2weeks or less. I had a lot of help n support n parts from Nick & Bison . I will keep u all up to date n will go into detail about my combo after I have some track numbers to compare to my 3.8 .I put all of my motors on kill I race a lot for money . This motor will not be babied. I will let all of you know just what this motor is capable of doing with time slips &youtube videos.
black owned
black pride
- Joined
- Jun 15, 2008
whats your combo consist of?
turbobob924
Member
- Joined
- May 28, 2001
subscribed.
I have had not issues with my 4.1 either. The increased torque is great.
I have had not issues with my 4.1 either. The increased torque is great.
- Joined
- Jan 3, 2012
No problems so far with mine so far. Even on conservative boost and timing it's a torque monster.
Ok the 4.1 is all togather now in my car &running . So far I was able to put 50 miles on my motor today due to the nice weather here in Det. Right now I'm just taking it slow n making sure all is well far as leaks n stuff like that ... Proper break in. The motor feels silky smooth sounds electric almost. At very low boost 7psi it feels just so strong. If this motor holds togather n works well I'm not ever goin back to a 109 block .Size matters this 256 feels real good . & the cost wasn't bad for pistons because I have a 4 inch bore .. Chevy pistons from Ross .My combo is a 35 over 4.1 9:1 compr fully ported irons 215/220 comp Hyd rllr 80lb injs & tt chip preci plenum fmic 6766 cea hoffer built 200r ptc nl atr headers n down pipe 3in / 3in atr exh..Next on my list is the racetronix dp. Again thanks to all of you for being so helpful & your continued support.. Aggressive Performance.
black owned
black pride
- Joined
- Jun 15, 2008
specs on the pistons?stoc length rods?
turbocamino1
turboholic
- Joined
- Jul 7, 2007
Very nice build...nice and simple! ...this will be my direction on my next motor. Which crank did you use? where you temped to stroke it?
turbobob924
Member
- Joined
- May 28, 2001
another happy customer!
Turbocamino I used my stock turbo 109 crank !!!!! Simply bcoz I've seen many stock cranks go 9.90s & 10s forever & hold up just fine . I did use billet mains & a set of Mollner rods from Full Throttle just bcoz mine needed some work. New forged cranks r stronger & heavier n the best thing since sliced bread but Detonation killz all . Remember its all in the Tune . 10% parts & 90% tune. A set of killer flowing heads some good fule & a lot of it & some compression will carry you a long ways. Just get in good with the guys that r goin fast for real n see what's really goin on..
