304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Last dyno it did 236hp/342tq and now 304hp/366tq both at the wheels (SAE). So that's a 68hp/24tq gain. I adjusted fuel and timing at the session but there were no major gains from initial (6hp/9tq). I'm very happy with it because it was what I was looking for. Engine is a 355 with 10:1 compression and 1 1/2" block hugger shorty headers with 2.5" true dual exhaust. I guess if I could fit some nice long tube headers power would be up nicely
The key upgraded parts are these;
- 52mm TB
- Ported upper plenum (by Corvette Plenums)
- AS&M big runners
- Edelbrock base
- AFR new Eliminator 180cc heads
- GMPP 1.6 full roller rockers
- Comp. Cams new XFI 268 cam
Not bad but more power to be had. Your exhaust system is killing you. You need a 1 3/4" header. Minimum of 2 1/2" from headers to cats or Y pipe and 3" there after. If a single cat you need to convert to dual high flow cats.
If your a/f ratio is anything like your old dyno pull that is costing you power. You need a custom tune. Again you are leaving a lot of power on the table.
Not bad but more power to be had. Your exhaust system is killing you. You need a 1 3/4" header. Minimum of 2 1/2" from headers to cats or Y pipe and 3" there after. If a single cat you need to convert to dual high flow cats.
If your a/f ratio is anything like your old dyno pull that is costing you power. You need a custom tune. Again you are leaving a lot of power on the table.
I know there is much more to had on exhaust (mainly headers). But this is not a Firebird/Camaro so there is no other option on headers unless I go custom and then there is still not much space. I did tuned fuel and timing on the dyno. Not much response on it except for the 6hp/9tq gained.
Then you've done VERY well with what you have to work with.
And you managed to shoe-horn a TPI motor into something with even LESS exhaust space than our cars? That's impressive.
300+ hp at the wheels is still decent, nothing to sneeze at there. Hell I'd love to be able to pull 300 at the wheels, I just don't think its going to happen with my 305.
that much power in a ity bity car like that, will fly. nice setup
great power curve too. let us know some track times if you ever get brave enough
you could probable smoke the tires though all 5 gears.
1 5/8" primaries would help. TPI motors dont make enough power to need 1 3/4" primaries. The dual 2.5" is fine.
There are huge threads from a couple years ago on 1 5/8" vs 1 3/4" headers in the exhaust forum. Also, those of us in SoCal making 320 to 375 RWHP with 1 3/4" headers beg to differ with you. I dont think SLP would have made 1 3/4" headers way back when if there wasnt something to be gained from them. Exhaust gas is hot and likes to expand. Also, today's cylinder heads have larger ports and raised ports, and the 1 5/8" headers are too small to effectively cover the port without some mismatch.
HD4mula, your combo looks great aside from the headers, but there isnt much you can do with it. I only gain a few HP and TQ at wide open throttle myself when tuning engines on the dyno. The biggest gains from tuning is in the low and midrange leading up to the peak points. Nice job!
Thanks all I agree with the headers. I could go to 1 5/8 but 1 3/4 may be pushing it. Then it probably would be shorties unless I go crazy and cut the trunk to hold a muffler. But then again that is not my goal. My goal was the 300 with the LTR look (which I love) and I got it. This car with 300rwhp is very fun to drive and already a hazard. Getting more may give me braging rights at cruise night but will also put me at risk much faster.
i assume you have tuning equipment b/c you said with fuel and timing you picked up 6 hp. my question is how did that xfi 268 work with the stock computer and factory prom if you have expirience with that i would love to know. thats the cam im thinking about going with when i put the tpi back on and i want something that will work well but work with stock equipment untill i can get my hands on some tuning equipment.
btw those are som very nice #'s you are putting down!
i assume you have tuning equipment b/c you said with fuel and timing you picked up 6 hp. my question is how did that xfi 268 work with the stock computer and factory prom if you have expirience with that i would love to know. thats the cam im thinking about going with when i put the tpi back on and i want something that will work well but work with stock equipment untill i can get my hands on some tuning equipment.
btw those are som very nice #'s you are putting down!
I'm sorry but the cam was never used on a stock ECM setup so I can't be of help with that. Maybe others may shime in with experience with cams with similar duration. It pulls about 17Hg of vacuum at idle if that is an indication.
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Quote:
Originally Posted by HD4mula
I'm sorry but the cam was never used on a stock ECM setup so I can't be of help with that. Maybe others may shime in with experience with cams with similar duration. It pulls about 17Hg of vacuum at idle if that is an indication.
ok cool thanks. im just trying to get a feel for a good cam to use that will work well with the stock ecm for a while until i can get my tuning equipment.
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Quote:
Originally Posted by MikeH
I like it a lot...i did v8 vegas and pintos years ago.
Where did you did you get it dyno tuned at? Im looking for a new place the one local to me closed up shop.
I did my own tunning at the dyno. Not sure if they tune too. Probably. They deal a lot with turbo Supras. The place is TPI. Located on US1 very close to Belvedere Rd.
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
I'm running a roller cam (post 87 block). Last couple days the clutch seems to be holding better so I think I may be able to take it to the track. After the 500 miles break in it was slipping on hard shifts 1-2nd and more in 2n-3rd. Last nigh it did better so maybe that was part of the break-in. Car weights about 2800-2900lbs and I am at 270lbs so it is around 3200 race weight. If I can hook up a little (no slicks here) I think I can hit high 12s. Will see.
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
You'll be fighting that clutch forever in a Fiero. My brother is running a 3.4L Twin Dual Cam motor out of a Lumina Z34 in his Fiero with nitrous on it- he's gone to a very exotic clutch setup to make it live, after trying all the stage 2-stage 4 type clutches available. He runs DRs out back and it hooks off the line so hard that the little tiny clutches in those transverse-mount manual transmissions take a heluva beating.
He doesn't make as much power as you do (even on nitrous) and 12s are no problem, if the clutch doesn't slip.
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Nice numbers. On the 1 3/4 headers. If you rev above 5500rpm the 1 3/4 really help. But there has been countless tests were only a few hp and sometimes 20-30ftlbs of torque are lost, at what rpm do you make peak torque and hp at. Is that right? Your hp peaks at only 4800rpm? Damn, thats pretty good.
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Yeah, I would be hesitant to add bigger headers to loose a lot of torque low and gain only 10hp at 5K or higher. But I think if I go crazy and fabricate some custom made long tubes I may get moer HP without loosing too much TQ or not at all. But that will take time. Right now I'm enjoying the ride
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Quote:
Originally Posted by HD4mula
Last dyno it did 236hp/342tq and now 304hp/366tq both at the wheels (SAE). So that's a 68hp/24tq gain. I adjusted fuel and timing at the session but there were no major gains from initial (6hp/9tq). I'm very happy with it because it was what I was looking for. Engine is a 355 with 10:1 compression and 1 1/2" block hugger shorty headers with 2.5" true dual exhaust. I guess if I could fit some nice long tube headers power would be up nicely
The key upgraded parts are these;
- 52mm TB
- Ported upper plenum (by Corvette Plenums)
- AS&M big runners
- Edelbrock base
- AFR new Eliminator 180cc heads
- GMPP 1.6 full roller rockers
- Comp. Cams new XFI 268 cam
Re: 304rwhp/366rwtq TPI Dyno - AFR heads, XFI268 cam etc.
Because I added all at once is hard to say but I think heads and cam were the bigest contributors. But of course the high flow intake needed to be there.
Nice 
