Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

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WhalenMike
Mike Whalen

(8 posts)

Registered:
06/05/2012 04:16PM

Main British Car:
1976 Triumph Spitfire

4a-ge swap
Posted by: WhalenMike
Date: June 09, 2012 08:16PM

I've decided to go with the 4age motor and also the trans from the ae86 corolla. Now in my area there are many shops selling these swap kits. My question is, what motor is better ? The silvertop or blacktop ? I would like to eventually turbo it, if that helps for an answer.

I've been reading and not really getting the answer, so maybe someone with this swap in their British car could help.

Regards,
Mike


BWA


(344 posts)

Registered:
04/13/2010 08:13PM

Main British Car:


Re: 4a-ge swap
Posted by: BWA
Date: June 11, 2012 12:05AM

Fourth Generation "Silver Top"
The fourth-generation 4A-GE engine was produced from 1991 to 1995. It has silver cam covers with chrome lettering, hence the nickname "silver top". This engine yet again features a completely new cylinder head which uses five valves per cylinder instead of four. It uses Toyota Variable Valve Timing (VVT) system on the intake cam, an increased compression ratio (10.5:1), and the intake system was replaced with a short manifold with individual throttles and velocity stacks, however the vane-type airflow meter was retained, requiring the use of a plenum. The previous 16-valve head used a sharply curved intake port, while the 20-valve engine used a very upright straight port. This engine produces 160 PS (118 kW) at 7,400 rpm with 16.5 kg•m (162 N•m) of torque at 5,200 rpm.
Fifth Generation "Black Top"
The fifth-generation 4A-GE engine produced from 1995 to 1998 is the final version of the 4A-GE engine and has black cam covers. This engine is commonly known as the "black top" due to the color of the valve cover, and yet again features an even higher compression ratio (11:1). The air flow sensor is replaced with a MAP sensor, the diameter of the four individual throttle bodies was increased from 42 mm to 45 mm, the exhaust port diameter was increased, the intake cam lift was increased from 7.9 mm to 8.2 mm and the intake ports were significantly improved in shape, contour and also the width at opening at the head was increased. Additionally, the black top had a lighter flywheel, a larger plenum, and revised rubber velocity stacks, and was also offered in 1997 with a six-speed C160 transaxle. This revision increased the power to 165 PS (121 kW) at 7,800 rpm with 16.5 kg•m (162 N•m) of torque at 5,600 rpm. These figures were issued by Toyota and are considered optimistic. It is assumed that Toyota ran the motor without ancillaries to inflate the power ratings, as some companies did before the adoption of the SAE J1349 rating standards in 2005. Still, the 'Blacktop' has become a favorite among enthusiasts and is used as an easy power upgrade for the early Toyota Corolla models, especially for use in the drift scene. Squeezing extra power from such a highly strung, naturally aspirated engine can be expensive because of the relatively high state of tuning of the stock motor, and most gains come from higher lift cams and engine management.

I got this info from Wikipedia so take it with a grain of salt. To me it looks like both engines are not suitable for turbocharging as the compression ratios are too high. If you put a turbo on either engine the lifespan of the engine will be short lived. If I am wrong on this please correct me but I think most engines that are set up for turbocharging have compression ratios in the 7.5 to 9 to 1 range.

Cheers
Byron


random rs
Dan Lynch

(6 posts)

Registered:
09/06/2012 09:48PM

Main British Car:


Re: 4a-ge swap
Posted by: random rs
Date: September 13, 2012 12:56PM

if you decide to go turbo route on a 20v engine you will need to source rods from a 16v 4agze (supercharged engine) you can use the 20v pistons and fit a slightly thicker (metal) headgasket..... its not a job to take on lightly to turbo a standard 4a, but in a spitfire you wouldnt really need much more than stanard hp, i mean the black top is rated at close to 165 fwhp...plenty in a car like the spit.

the vvt can be a right pain in the ass though, yes its good for a bit of pull but only works at certain throttle positions, too much to go into here really, but the intake pully only has a lifespan of 100-120k kilometers, so if you go down that road its best either getting an engine that has had this replaced or even budget for a new intake pully.... it also works of a solenoid which can cause a rattley sound too kinda like a diesel when there on the way out.....


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