Texas Speed 427 low NA power
 

Have a TSP 427 (LS3 based), however I'm not getting the power expected. Expecting 525-550rwph but only getting 488rwhp. Tuner was thinking possibly the cam is too small for the combo? Was a custom grind cam from TSP which was installed with the long block by them.

The real kicker here is the peak power is at 5900 then drops off which makes me think it may be a cam issue?

I called Texas Speed tech support and the tech seemed confused as well and wanted me to check a ton of things that I feel like I shouldn't be doing since they built the long block... IDK, maybe I'm expecting too much lol.

Wanted me to pull timing cover, confirm cam was degreed correctly, pull valve covers check rockers, measure/check for bent pushrods, pull heads and check lifters.

Before I contact my salesman because I have no plans on tearing in to a 19k engine I paid them to build, wanted to check with you guys to see if you have any ideas/had an issue similar or see what I may be missing? Side note, this is an engine built for boost (F1A ProCharger) that is running NA atm.

Engine was broke in using TSP break in procedures, break in tune, drove with break in tune while breaking in clutch (about 1000 miles or so), then dyno tuned which yielded low numbers.

Below are details about the car and drive train
2011 Camaro SS Manual
Engine-
LS3 based 427
4.000 stroke, 4.125 bore
PRC 260cc heads
Rollermaster double roller timing set
TSP Chromoly pushrods
-11cc Wiseco forged pistons (equaling 10.7:1 Compression)
Johnson 2110r lifters
TSP Roller rockers
Cam (See cam card attachment)
Fuel Injection Clinic 1200cc injectors
Stock LS3 intake and throttle body

Texas Speed 2" long tube headers
Texas Speed Mid and Axel back w/ TSP Mufflers
TR6060 (Stock)
McLeod RXT Clutch
1 Piece DSS Drive shaft
2013 ZL1 Cradle (Diff/Axels) 3.73 gears
BMR poly cradle and diff bushings

Any ideas would be greatly appreciated!

I would be interested to know if your clutch is fully broke in and also what the dyno would say if correction was set to SAE. McLeod recommends something like 1500 clutch cycles and no reference to mileage.

I put well over 1500 clutch cycles. Most of that mileage is in town in stop and go traffic. I just started driving it to the gym everyday just to get the clutch cycles in lol.

Mustang dyno?

It’s a Dynajet

I would cut the filter and check it.

I mean they could have it loaded differently. But still kind of low for the combo that you have.

I don't think your expectations are unreasonable. You mentioned the engine was built for boost but that cam and compression seem like a healthy N/A combo to me. Maybe there is a head or intake component mismatch causing the power drop-off after 5900. That engine should be pulling hard up to about 6500. $19K and they want YOU to inspect and/or troubleshoot their build? I wouldn't be too happy either.

If this made 300-400 hp then I might would expect TSP to want the engine back to check it out. At those marginal somewhat low numbers, I'm not sure exactly what TSP can do from Texas. This could be a dyno/tuning issue as far as TSP knows. The fair compromise is that TSP agrees to have a local professional check things out and if something is found TSP pays for the inspection. If not it's on the OP. Otherwise motor needs to come out and sent back to TSP and cost is still on whoever was wrong.

^Agreed. The specs are close to my old polluter cam, and I made 490ish/500 on my sbe ls3.


Have tsp foot the bill.

What if nothing is found to be wrong?

Then of course op is on the hook.

I've been reluctant to say anything because I don't really understand what a ls3 based 427 is. I didn't even know you could bore out a ls3 to 4.125. Someone school me please.

EDITED: The EXECUTIONER from TSP is a re-sleeved LS3 block punched to 427