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Effect of a 38mm restrictor on an LS7

Effect of a 38mm restrictor on an LS7

Author
Discussion

Boosted LS1

16,605 posts

184 months

Monday 18th September
quotequote all
You can buy LS diameter flexplates that will take TH convertors. How have you got on with the TH350? Have you done any mod's to it?

C Lee Farquar

Original Poster:

1,945 posts

140 months

Monday 18th September
quotequote all
I can't remember exactly what I did when I fitted the LS7, but I have a Hughes flexplate designed for the TH350 converter. I ended up buying two torque converters as the first had too high stall. It was supposed to fit the LS engine but didn't. We had to weld a bit on one (on the bit that locates the crank) and turn a bit off the other. In 2006 information was a bit thinner on the ground for Gen 1V engines and I don't think the transmission people were that knowledgeable. I'm hoping the 2006 LS7 crank rear is identical to a 2017 LS3.

My TH350 is manual shift with (some) engine braking and a few uprated bits. I've snapped the input shaft but no problems since changing to an uprated one (300m Coan one IIRC)

I did the last rebuild with a fastidious older friend of mine. We took a while and ensured all the measurements were optimal, the improvement was significant.

Edited by C Lee Farquar on Monday 18th September 20:13

Boosted LS1

16,605 posts

184 months

Monday 18th September
quotequote all
So, do you the the manual shift? I have TH400 to convert but I've never used an auto.

C Lee Farquar

Original Poster:

1,945 posts

140 months

Monday 18th September
quotequote all
Come again? smile

C Lee Farquar

Original Poster:

1,945 posts

140 months

Tuesday 19th September
quotequote all
Yes, it only manual shifts and I have a gear vendors overdrive.
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Boosted LS1

16,605 posts

184 months

Tuesday 19th September
quotequote all
Manual shift does appeal to me and an overdrive appeals even more especially for long distance driving. :-)

stevieturbo

12,726 posts

171 months

Wednesday 20th September
quotequote all
Just a pity nobody offers aftermarket controllers for the likes of 6L80e !

C Lee Farquar

Original Poster:

1,945 posts

140 months

Wednesday 20th September
quotequote all
There's a lot more choice now, mines been in about 15 years. I'm hoping to go to a sequential once my house is built when hopefully there will be a little more money about!

C Lee Farquar

Original Poster:

1,945 posts

140 months

Wednesday 11th October
quotequote all
Christmas comes early smile


Max_Torque

11,766 posts

141 months

Wednesday 11th October
quotequote all
C Lee Farquar said:
Christmas comes early smile

And Santa's had to Trade In his Slay for something more modern too.... ;-)

C Lee Farquar

Original Poster:

1,945 posts

140 months

Thursday 12th October
quotequote all
Unfortunately this one has a 'made in Mexico' sticker rather than 'handbuilt by Hank in Wixon'


stevieturbo

12,726 posts

171 months

Thursday 12th October
quotequote all
C Lee Farquar said:
Unfortunately this one has a 'made in Mexico' sticker rather than 'handbuilt by Hank in Wixon'
better not tell Trump !!

C Lee Farquar

Original Poster:

1,945 posts

140 months

Thursday 12th October
quotequote all
Trump's attitude did cross my mind. So much Chevy stuff is made in Mexico.

Fortunately I didn't find any brush bristles when changing the sump.

C Lee Farquar

Original Poster:

1,945 posts

140 months

Wednesday 15th November
quotequote all
It's all in and running

running in

Luckily all of the bolt holes were in the same position as the eleven year older LS7. A big time save was being able to use the older LS7 throttle assembly. This fits neatly in the frame, whereas the GM supplied LS3 stem is a clumsy great big thing. All the ancillaries fitted. Flexplate needed a little flettling

As it turns out all of the sensors are the same, other than the MAF, and I could have used my existing engine loom and ECU. However it was past it's best and I did have an occasional misfire from the old engine.


Happy Jim

563 posts

163 months

Wednesday 15th November
quotequote all
beer

I was not expecting that! Superb Sir ;-)

Looks great

Jim

Boosted LS1

16,605 posts

184 months

Wednesday 15th November
quotequote all
Wow what fun that looks like :-)

C Lee Farquar

Original Poster:

1,945 posts

140 months

Wednesday 15th November
quotequote all
13 days from collecting the engine, tuned from the data log, to on a trailer on the way to France smile

Longest delay was Partsworld didn't have a loom and controller and their shipment was delayed. After a week I realised I didn't need the specific ecu for my tune as I was changing the cam. So I had a 480hp controller and used EFI Live. Well, I plugged it in and Luis Sola made some pretty graphs.

stevieturbo

12,726 posts

171 months

Wednesday 15th November
quotequote all
Be interesting to see how it performs compared to the 7

C Lee Farquar

Original Poster:

1,945 posts

140 months

Thursday 16th November
quotequote all
Anecdotally this engine is more free reving with the restrictor. There may be less initial punch, but most times I'm grip limited anyway.

I did do a 1/4 mile at Long Marston with the LS7 without the restrictor, 12 seconds on my only run so not in your league. I could try that again with the LS3 but I have put a cam in to work best with the restrictor.